K&B .65 Sportster (yup, more from me)
#26
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: proptop
How does the plug look...might need a new one?
How does the plug look...might need a new one?
I think there is a chunk of crap that got into the carb or something. I just find it odd that it ran so much different today and it ran fine yesterday.. Compression is the same as its always been, and no "tight" spots except at TDC. (cant notice it with the plug in but with the plug out I can still feel a little pinch at TDC. The muffler baffle has been removed to help with the rich transition.
#27
My Feedback: (8)
RE: K&B .65 Sportster (yup, more from me)
One thing that just came to mind...
You mentioned that you think it has an early carb on it?
Could the disc be moving on it's own just a little bit?
Sometimes, when o rings get some age to 'em, they get hard and the carb adj. can drift a bit.
You mentioned that you think it has an early carb on it?
Could the disc be moving on it's own just a little bit?
Sometimes, when o rings get some age to 'em, they get hard and the carb adj. can drift a bit.
#28
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: proptop
One thing that just came to mind...
You mentioned that you think it has an early carb on it?
Could the disc be moving on it's own just a little bit?
Sometimes, when o rings get some age to 'em, they get hard and the carb adj. can drift a bit.
One thing that just came to mind...
You mentioned that you think it has an early carb on it?
Could the disc be moving on it's own just a little bit?
Sometimes, when o rings get some age to 'em, they get hard and the carb adj. can drift a bit.
After it stalls, it will restart with 2 or 3 flips of the prop. Idle is nice and smooth and up to about 4000rpm is nice and smooth. In fact it runs pretty nice up to just before WOT. The last 1/5th throttle is where it will sag. The weird part is I'll hold the boat on shore, run the engine to WOT and get it just singing.. Sounds great, no sag. Its only after its in the water and moving forward under near-full load that it gets saggy in the WOT area. It blows lots of smoke and oil from the exhaust while holding it stationary and revving it. This is where I'm confused.
#29
My Feedback: (8)
RE: K&B .65 Sportster (yup, more from me)
Hmmm...ok...
I just went and dug mine out of the box. I have an early .65 Sportster as well. No bushing and the needle is on the carb. I however have an eccentric adj. screw for the brass low speed adj. disc.
If you don't have the eccentric though, what's to keep the disc in place but o ring friction? (similar to Perry carbs )
I'm just thinking that if the disc rotated a few degrees...it doesn't take much...it can effect the entire r.p.m. range, not just the idle.
I just went and dug mine out of the box. I have an early .65 Sportster as well. No bushing and the needle is on the carb. I however have an eccentric adj. screw for the brass low speed adj. disc.
If you don't have the eccentric though, what's to keep the disc in place but o ring friction? (similar to Perry carbs )
I'm just thinking that if the disc rotated a few degrees...it doesn't take much...it can effect the entire r.p.m. range, not just the idle.
#30
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: proptop
Hmmm...ok...
I just went and dug mine out of the box. I have an early .65 Sportster as well. No bushing and the needle is on the carb. I however have an eccentric adj. screw for the brass low speed adj. disc.
If you don't have the eccentric though, what's to keep the disc in place but o ring friction? (similar to Perry carbs )
I'm just thinking that if the disc rotated a few degrees...it doesn't take much...it can effect the entire r.p.m. range, not just the idle.
Hmmm...ok...
I just went and dug mine out of the box. I have an early .65 Sportster as well. No bushing and the needle is on the carb. I however have an eccentric adj. screw for the brass low speed adj. disc.
If you don't have the eccentric though, what's to keep the disc in place but o ring friction? (similar to Perry carbs )
I'm just thinking that if the disc rotated a few degrees...it doesn't take much...it can effect the entire r.p.m. range, not just the idle.
I dont know if it matters, but the last 4 or 5 times I started the engine it kept starting in reverse... It hasnt done that much since I started it on the stand during break-in. Perhaps I'll go to the hardware store and get a couple new O-rings and see if that makes a difference. I did adjust the idle mixture richer just a tick, that seemed to drop the idle speed down a little bit but it seemed to run okay and throttle up decently but once I hit WOT it just sagged off. I know the servo is opening the throttle all the way and its returning to the idle stop each time you let go of the trigger.
I know the spraybar hasnt changed positions as far as I know - this is pressed into the barrel. When I have some daylight tomorrow morning, I'll take a look at it and see if maybe the spraybar did move. Thats the only other thing that I see that could have changed. The idle mix doesnt get adjusted much because its too rich even at its leanest point. When cutting fuel the engine, the engine will idle for several seconds (5-10 seconds on average) before it stalls. It does not speed up or down, it just very slowly slows down a little bit until it just quits. At this adjustment, its in the full lean position.
There is something amiss with the engines the military used on their Drone target planes that used these engines but they are ran WOT and thats it. I think there is a fault with the size of the spraybar orifice and/or idle mixture orifice. The orifices line up perfectly when installed in the carb, I just dont know if they were mis-cut when manufactured or what.
#31
Senior Member
My Feedback: (14)
RE: K&B .65 Sportster (yup, more from me)
You must set the high speed needle for max rpm, minus 200-300 rpm with only an ounce of fuel in the tank. Then the engine's mixture will remain rich enough to prevent sagging as you burn off the fuel in the tank. Yes, the engine will sound rich when you fill the tank and restart after setting it this way. DON'T TOUCH THE NEEDLE VALVE! If you do, you'll be right back to sagging when away from shore after initial launch.
This happens because your engine uses suction to pull fuel to the carb. This is a very weak force and it is sensitive to the fuel pressure head.
Ed Cregger
This happens because your engine uses suction to pull fuel to the carb. This is a very weak force and it is sensitive to the fuel pressure head.
Ed Cregger
#32
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: NM2K
You must set the high speed needle for max rpm, minus 200-300 rpm with only an ounce of fuel in the tank. Then the engine's mixture will remain rich enough to prevent sagging as you burn off the fuel in the tank. Yes, the engine will sound rich when you fill the tank and restart after setting it this way. DON'T TOUCH THE NEEDLE VALVE! If you do, you'll be right back to sagging when away from shore after initial launch.
This happens because your engine uses suction to pull fuel to the carb. This is a very weak force and it is sensitive to the fuel pressure head.
Ed Cregger
You must set the high speed needle for max rpm, minus 200-300 rpm with only an ounce of fuel in the tank. Then the engine's mixture will remain rich enough to prevent sagging as you burn off the fuel in the tank. Yes, the engine will sound rich when you fill the tank and restart after setting it this way. DON'T TOUCH THE NEEDLE VALVE! If you do, you'll be right back to sagging when away from shore after initial launch.
This happens because your engine uses suction to pull fuel to the carb. This is a very weak force and it is sensitive to the fuel pressure head.
Ed Cregger
I pulled the carb barrel and needle valve assembly out and looked it over. 2 little specs of what looked like plant matter. The engine did get a little water spray the other day. Otherwise, the inside of the carb looks fine. I'll run it at home here since I still have 2 or 3 more cycles to do on the TT .46, and go hit the pond..
#33
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: 1QwkSport2.5r
...I pulled the carb barrel and needle valve assembly out and looked it over. 2 little specs of what looked like plant matter. The engine did get a little water spray the other day. Otherwise, the inside of the carb looks fine. ...
...I pulled the carb barrel and needle valve assembly out and looked it over. 2 little specs of what looked like plant matter. The engine did get a little water spray the other day. Otherwise, the inside of the carb looks fine. ...
Maybe you want to fit an intake air filter? Or, are you trying to be green and burn biomass?
Regards, Richard
#34
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: spaceworm
Maybe you want to fit an intake air filter? Or, are you trying to be green and burn biomass?
Regards, Richard
ORIGINAL: 1QwkSport2.5r
...I pulled the carb barrel and needle valve assembly out and looked it over. 2 little specs of what looked like plant matter. The engine did get a little water spray the other day. Otherwise, the inside of the carb looks fine. ...
...I pulled the carb barrel and needle valve assembly out and looked it over. 2 little specs of what looked like plant matter. The engine did get a little water spray the other day. Otherwise, the inside of the carb looks fine. ...
Maybe you want to fit an intake air filter? Or, are you trying to be green and burn biomass?
Regards, Richard
All kidding aside - None of the orifices were clogged or blocked with anything so from what I can tell fuel metering isnt being affected. There was a fair amount of oil in the original pressure line I had on the engine so I changed it for a new piece that was clean thinking the oil was obstructing the tank pressure reducing fuel flow. I still havent ran it today yet but I should be able to get at it shortly.
#35
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
Ok.. survey says: 10,500rpm on a 13x5 MAS. It took me 3 tries to get it to stay running long enough to get a good reading. It keeps quitting at WOT. No air bubbles in fuel line to carb when engine is at speed - just enough fuel to keep the clunk submersed. It is acting like fuel is just flat out cut off and it just quits. It will start right back up though, mostly in reverse. The "peak" area on the high speed needle seems a lot wider than previous runs. With the needle set 200-300rpm rich of peak, the transition is rough. Idle mix has to be full lean. It seems to idle pretty rough at 2500 so the idle speed is about 3200rpm. This is still running on the new glow plug I swapped yesterday, Sig 10% nitro 20% oil. This fuel runs great in the TT .46Pro which tached a 10x6 at 14,980rpm. Not too much relevance there, except its the same fuel that runs fine in one and not-so-fine in the other..... ideas?
#36
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
I pulled the top of the engine apart - inside of combustion chamber is relatively clean but has some castor film on it. Darker brown in color both cylinder head and top of piston. No pitting in the head or the piston. Piston has shiny wear spots in the normal places - top and bottom of piston. The conrod has a little play side to side but nothing up and down. Looks pretty good inside.. I think I'll pull the carb apart again and make sure there isn't anything else clogging something. It literally will run WOT for a few seconds and then just quit. Glow plug is clean and new still, not melted or anything. I'm just not sure....
#37
Senior Member
My Feedback: (14)
RE: K&B .65 Sportster (yup, more from me)
My Sportster .28 would not swing a prop larger than a 9x4 MAS until well after a gallon of fuel had been burned. Keep in mind that I wasn't using a fuel with much castor oil, which I attribute to the extended break-in period. It was S&W 10% nitro with mostly synthetic oil and a tad of castor oil. It did get to where it would spin that 9x4 at a pretty good rpm and it would stay running during the expected duration (as long as it had fuel). I tried running a 10x4 Graupner nylon prop, but the little .28 would overheat and quit. It was behaving just as though it wasn't broken-in. I did see another fellow running a prop larger than a 9x4 on a Sportster .28, but he was burning fuel with 22% castor oil, no synthetic oil.
The few K&B .65 Sportsters that I flew or saw flying (none belonged to me) back then were spinning 11x7 wood props (Zingers). They ran well on the 11x7, but refused to pull larger props with heavier loads unless the fuel was made with all castor oil lubrication. Those folks running 14x6 props must have had a lot of running time on their .65's or were burning fuel with all castor oil.
Ed Cregger
The few K&B .65 Sportsters that I flew or saw flying (none belonged to me) back then were spinning 11x7 wood props (Zingers). They ran well on the 11x7, but refused to pull larger props with heavier loads unless the fuel was made with all castor oil lubrication. Those folks running 14x6 props must have had a lot of running time on their .65's or were burning fuel with all castor oil.
Ed Cregger
#38
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: NM2K
My Sportster .28 would not swing a prop larger than a 9x4 MAS until well after a gallon of fuel had been burned. Keep in mind that I wasn't using a fuel with much castor oil, which I attribute to the extended break-in period. It was S&W 10% nitro with mostly synthetic oil and a tad of castor oil. It did get to where it would spin that 9x4 at a pretty good rpm and it would stay running during the expected duration (as long as it had fuel). I tried running a 10x4 Graupner nylon prop, but the little .28 would overheat and quit. It was behaving just as though it wasn't broken-in. I did see another fellow running a prop larger than a 9x4 on a Sportster .28, but he was burning fuel with 22% castor oil, no synthetic oil.
The few K&B .65 Sportsters that I flew or saw flying (none belonged to me) back then were spinning 11x7 wood props (Zingers). They ran well on the 11x7, but refused to pull larger props with heavier loads unless the fuel was made with all castor oil lubrication. Those folks running 14x6 props must have had a lot of running time on their .65's or were burning fuel with all castor oil.
Ed Cregger
My Sportster .28 would not swing a prop larger than a 9x4 MAS until well after a gallon of fuel had been burned. Keep in mind that I wasn't using a fuel with much castor oil, which I attribute to the extended break-in period. It was S&W 10% nitro with mostly synthetic oil and a tad of castor oil. It did get to where it would spin that 9x4 at a pretty good rpm and it would stay running during the expected duration (as long as it had fuel). I tried running a 10x4 Graupner nylon prop, but the little .28 would overheat and quit. It was behaving just as though it wasn't broken-in. I did see another fellow running a prop larger than a 9x4 on a Sportster .28, but he was burning fuel with 22% castor oil, no synthetic oil.
The few K&B .65 Sportsters that I flew or saw flying (none belonged to me) back then were spinning 11x7 wood props (Zingers). They ran well on the 11x7, but refused to pull larger props with heavier loads unless the fuel was made with all castor oil lubrication. Those folks running 14x6 props must have had a lot of running time on their .65's or were burning fuel with all castor oil.
Ed Cregger
I do also have a feeling this engine never will throttle well unless someone will tell me or I figure out what exactly causes them to run crappy between idle and WOT. The low speed mixture seems just a tad rich but in the full lean position gives me a smooth pinch test. No speed-up or quick stall. (this is before the last carb cleaning) If when I run it it does the same thing its been doing the last few times it ran I'm gonna make a short video and post it. I think I will have to bite the bullet and order some all-castor nitro fuel.. Nobody locally will order it for me so I'll probably order 2 gallons. Of course the all-castor fuel from SIG and Byrons doesnt come in quart bottles so hazmat fees apply. Do these engines lose a lot of performance if ran on FAI Castor fuel?
#39
Senior Member
My Feedback: (14)
RE: K&B .65 Sportster (yup, more from me)
None of the K&B Sportster .65 engines that I have ran (belonged to other folks) had a problem with a funky transition from idle to wide open throttle, once broken-in. The latter can take far longer than a normal engine. Remember, the piston is chromed, NOT the cylinder. So, we can expect the engines to run a little differently from normal.
In fact, I was surprised that such funky looking carbs could work so well, but work well they did. See if someone else that owns one of those engines will let you swap carbs for a float or two.
Good luck in your exploits and hang in there.
Ed Cregger
In fact, I was surprised that such funky looking carbs could work so well, but work well they did. See if someone else that owns one of those engines will let you swap carbs for a float or two.
Good luck in your exploits and hang in there.
Ed Cregger
#40
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: NM2K
None of the K&B Sportster .65 engines that I have ran (belonged to other folks) had a problem with a funky transition from idle to wide open throttle, once broken-in. The latter can take far longer than a normal engine. Remember, the piston is chromed, NOT the cylinder. So, we can expect the engines to run a little differently from normal.
In fact, I was surprised that such funky looking carbs could work so well, but work well they did. See if someone else that owns one of those engines will let you swap carbs for a float or two.
Good luck in your exploits and hang in there.
Ed Cregger
None of the K&B Sportster .65 engines that I have ran (belonged to other folks) had a problem with a funky transition from idle to wide open throttle, once broken-in. The latter can take far longer than a normal engine. Remember, the piston is chromed, NOT the cylinder. So, we can expect the engines to run a little differently from normal.
In fact, I was surprised that such funky looking carbs could work so well, but work well they did. See if someone else that owns one of those engines will let you swap carbs for a float or two.
Good luck in your exploits and hang in there.
Ed Cregger
Randy at Mecoa said the military issued sportsters are "spec'd to run WOT" and "they don't throttle well". He told me I needed to replace the carburetor. What I dont understand is many of the old sportsters use the same style carb - needle on the carb body, and they run like a champ and throttle well. I'm trying to figure out whats different with my military carb compared to an early sportster carb. My engine's vintage is 1991 or so. The idle orifice on the mixture disk is so small I dont think I can measure the I.D. of the hole. The spraybar I would have a better chance at a good measurement. I have a feeling its in the spraybar or mixture disk or both that is the cause of some of the problems I am having with transitioning from about 4000rpm to 3/4-WOT. I wish I could see a normal sportster .65 running and throttling so I know what it "should" run/sound like. I'll have to keep messing with it and if it stays as consistent as it has, I'll order a new spraybar and mixture disk/o-rings. If that doesn't work, well... I don't have a plan C yet.
#41
Join Date: Nov 2006
Location: lisbon,
OH
Posts: 200
Likes: 0
Received 0 Likes
on
0 Posts
RE: K&B .65 Sportster (yup, more from me)
Its bigger than it looks, 32" long x 18" wide. The first couple times I ran it, it seemed like the .65 was too small for it given its weight. Since I've been switching props and the speed is getting better, I'm getting to be a bit happier with it. This same boat design and construction with a 91FX ran 38mph+.
The 38mph was with a .61fx apc12/4. The 91 was added later just too see how high she would fly
#42
Senior Member
Join Date: Sep 2006
Location: Southeastern,
OH
Posts: 239
Likes: 0
Received 0 Likes
on
0 Posts
RE: K&B .65 Sportster (yup, more from me)
Does your spray bar have a small slit where the hole is in the spray bar? I looked at the disc/spray bar assy. on my 65 so I know there is a very small slit cut where the spray bar hole is. The only way I know to measure the holes near the disc and the hole in the spray bar is to check them with drill bits. Which ever one(s) fits the holes is the size of the holes.
I'm guessing your problem is the spray bar either not slit correctly or not slit at all. If the slit not there or screwed up, this would affect the low end adjustment. The slit helps the fuel draw at low speed/idle. The rotation of the disc changes the location of the slit in relation to the air draw thru the carb.
I'm guessing your problem is the spray bar either not slit correctly or not slit at all. If the slit not there or screwed up, this would affect the low end adjustment. The slit helps the fuel draw at low speed/idle. The rotation of the disc changes the location of the slit in relation to the air draw thru the carb.
#43
Senior Member
My Feedback: (14)
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: 1QwkSport2.5r
Well, the problem is nobody that I know of has any of these engines, much less any experience with them. There is 1 guy at my LHS that has ran several sportster engines so I have gotten some info from him that tested whether there is any needle compensation going on. He gave me a list of different combinations to try with mixture settings to get the transition clean. None of which worked. Now I understand the construction of the engine, and how it needs a long time to break-in. Based on the information I've gotten, it should be throttling pretty well at this point in time. A hiccup or a burp here and there I would expect. A rough, smokey, misfiring, snotty transition - No.
Randy at Mecoa said the military issued sportsters are ''spec'd to run WOT'' and ''they don't throttle well''. He told me I needed to replace the carburetor. What I dont understand is many of the old sportsters use the same style carb - needle on the carb body, and they run like a champ and throttle well. I'm trying to figure out whats different with my military carb compared to an early sportster carb. My engine's vintage is 1991 or so. The idle orifice on the mixture disk is so small I dont think I can measure the I.D. of the hole. The spraybar I would have a better chance at a good measurement. I have a feeling its in the spraybar or mixture disk or both that is the cause of some of the problems I am having with transitioning from about 4000rpm to 3/4-WOT. I wish I could see a normal sportster .65 running and throttling so I know what it ''should'' run/sound like. I'll have to keep messing with it and if it stays as consistent as it has, I'll order a new spraybar and mixture disk/o-rings. If that doesn't work, well... I don't have a plan C yet.
ORIGINAL: NM2K
None of the K&B Sportster .65 engines that I have ran (belonged to other folks) had a problem with a funky transition from idle to wide open throttle, once broken-in. The latter can take far longer than a normal engine. Remember, the piston is chromed, NOT the cylinder. So, we can expect the engines to run a little differently from normal.
In fact, I was surprised that such funky looking carbs could work so well, but work well they did. See if someone else that owns one of those engines will let you swap carbs for a float or two.
Good luck in your exploits and hang in there.
Ed Cregger
None of the K&B Sportster .65 engines that I have ran (belonged to other folks) had a problem with a funky transition from idle to wide open throttle, once broken-in. The latter can take far longer than a normal engine. Remember, the piston is chromed, NOT the cylinder. So, we can expect the engines to run a little differently from normal.
In fact, I was surprised that such funky looking carbs could work so well, but work well they did. See if someone else that owns one of those engines will let you swap carbs for a float or two.
Good luck in your exploits and hang in there.
Ed Cregger
Randy at Mecoa said the military issued sportsters are ''spec'd to run WOT'' and ''they don't throttle well''. He told me I needed to replace the carburetor. What I dont understand is many of the old sportsters use the same style carb - needle on the carb body, and they run like a champ and throttle well. I'm trying to figure out whats different with my military carb compared to an early sportster carb. My engine's vintage is 1991 or so. The idle orifice on the mixture disk is so small I dont think I can measure the I.D. of the hole. The spraybar I would have a better chance at a good measurement. I have a feeling its in the spraybar or mixture disk or both that is the cause of some of the problems I am having with transitioning from about 4000rpm to 3/4-WOT. I wish I could see a normal sportster .65 running and throttling so I know what it ''should'' run/sound like. I'll have to keep messing with it and if it stays as consistent as it has, I'll order a new spraybar and mixture disk/o-rings. If that doesn't work, well... I don't have a plan C yet.
Being a military configured engine, the "problem" could be anything from porting to the carburetor. The civilian versions throttled well, just like any good R/C engine would throttle. I've seen these engines on the auction sites for as little as $30. A new carb is going to cost you that much. See if you can get one with the bushings installed and low run time. Then you can figure out your engine, or sell it and keep the good one.
Ed Cregger
#44
Senior Member
Join Date: Aug 2003
Location: Seymour, IN,
Posts: 831
Likes: 0
Received 0 Likes
on
0 Posts
RE: K&B .65 Sportster (yup, more from me)
I know you've just about pulled your hair out on this engine, but I have an idea. In two strokes, I've only run K&B and Fox engines for years now and experimenting with fuel, props and plugs, I've found that the American engines just perform most reliably, overall, on idle bar plugs. Fireball, K&B and Fox idle bar plugs all work well with Fireball and K&B appearing to be ever so slightly better in SOME engines. Don't want to start a plug debate here, but you didn't seem to give any info on the plug your using, but give one of these a try and note any change, hopefully for the good.
#45
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: AutoMike
I know you've just about pulled your hair out on this engine, but I have an idea. In two strokes, I've only run K&B and Fox engines for years now and experimenting with fuel, props and plugs, I've found that the American engines just perform most reliably, overall, on idle bar plugs. Fireball, K&B and Fox idle bar plugs all work well with Fireball and K&B appearing to be ever so slightly better in SOME engines. Don't want to start a plug debate here, but you didn't seem to give any info on the plug your using, but give one of these a try and note any change, hopefully for the good.
I know you've just about pulled your hair out on this engine, but I have an idea. In two strokes, I've only run K&B and Fox engines for years now and experimenting with fuel, props and plugs, I've found that the American engines just perform most reliably, overall, on idle bar plugs. Fireball, K&B and Fox idle bar plugs all work well with Fireball and K&B appearing to be ever so slightly better in SOME engines. Don't want to start a plug debate here, but you didn't seem to give any info on the plug your using, but give one of these a try and note any change, hopefully for the good.
Idle bar plugs are designed for non schneurle engines with baffles on the piston top. The baffle directed the incoming fuel from the case to the top of the cylinder. That however, could cause the glow plug to be cooled by that charge. The idle bar helped shield the glow element form that incoming fuel charge. Schneurle engines angle the inlet ports to swirl the mixture and have a flat top piston, so glow plug cooling should not be an issue.
That said, I have used idle bar plugs in non baffle engines and have not had any problems. I just don't know if it would solve any problems, since the.65 is a schneurle design, is it not? It won't hurt to try though. Another option is a Fox Miracle plug also known as a hose nose, which sets the glow element in a kinda recess. I think the OS F plug is like this !?!.
Good luck, I have K&B engines .29, .35, .40, .61 and .65 and love em all.
Regards, Richard
#46
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: hooty301
Hello there, looks like your have fun with your boat.
The 38mph was with a .61fx apc12/4. The 91 was added later just too see how high she would fly
Its bigger than it looks, 32'' long x 18'' wide. The first couple times I ran it, it seemed like the .65 was too small for it given its weight. Since I've been switching props and the speed is getting better, I'm getting to be a bit happier with it. This same boat design and construction with a 91FX ran 38mph+.
The 38mph was with a .61fx apc12/4. The 91 was added later just too see how high she would fly
#47
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: NM2K
Being a military configured engine, the ''problem'' could be anything from porting to the carburetor. The civilian versions throttled well, just like any good R/C engine would throttle. I've seen these engines on the auction sites for as little as $30. A new carb is going to cost you that much. See if you can get one with the bushings installed and low run time. Then you can figure out your engine, or sell it and keep the good one.
Ed Cregger
Being a military configured engine, the ''problem'' could be anything from porting to the carburetor. The civilian versions throttled well, just like any good R/C engine would throttle. I've seen these engines on the auction sites for as little as $30. A new carb is going to cost you that much. See if you can get one with the bushings installed and low run time. Then you can figure out your engine, or sell it and keep the good one.
Ed Cregger
ORIGINAL: madman75
Does your spray bar have a small slit where the hole is in the spray bar? I looked at the disc/spray bar assy. on my 65 so I know there is a very small slit cut where the spray bar hole is. The only way I know to measure the holes near the disc and the hole in the spray bar is to check them with drill bits. Which ever one(s) fits the holes is the size of the holes.
I'm guessing your problem is the spray bar either not slit correctly or not slit at all. If the slit not there or screwed up, this would affect the low end adjustment. The slit helps the fuel draw at low speed/idle. The rotation of the disc changes the location of the slit in relation to the air draw thru the carb.
Does your spray bar have a small slit where the hole is in the spray bar? I looked at the disc/spray bar assy. on my 65 so I know there is a very small slit cut where the spray bar hole is. The only way I know to measure the holes near the disc and the hole in the spray bar is to check them with drill bits. Which ever one(s) fits the holes is the size of the holes.
I'm guessing your problem is the spray bar either not slit correctly or not slit at all. If the slit not there or screwed up, this would affect the low end adjustment. The slit helps the fuel draw at low speed/idle. The rotation of the disc changes the location of the slit in relation to the air draw thru the carb.
The engine runs well at idle and off-idle rpms (up to about 4500) And once it "cleans out" for the first time, it will throttle fine as long as you keep the rpms up past 4500-5000rpms or only let it come back to idle for just a couple seconds. I will take pictures of my carburetor parts and post them when I am home from work. I dont know if I have any drill bits small enough to measure the holes but I will try to zoom it in enough to see the detail and compare to yours.
#49
Thread Starter
RE: K&B .65 Sportster (yup, more from me)
ORIGINAL: madman75
Hey 1QwkSport2.5r ,
I sent you a PM.
Hey 1QwkSport2.5r ,
I sent you a PM.
Here are links (the pics are pretty big) to 3 pics I took of my barrel and spraybar on the running engine.
http://s153.photobucket.com/albums/s...t=IMG_0212.jpg
http://s153.photobucket.com/albums/s...t=IMG_0213.jpg
http://s153.photobucket.com/albums/s...t=IMG_0214.jpg
#50
Senior Member
Join Date: Sep 2006
Location: Southeastern,
OH
Posts: 239
Likes: 0
Received 0 Likes
on
0 Posts
RE: K&B .65 Sportster (yup, more from me)
Can you get a better picture of the spray bar slit? From what I can see in the picture, the slit looks bigger than the one in my carb. Maybe with a better picture I might be able to tell more but it does look like the slit is wrong. I had a carb many years ago that wasn't right and K&B sent me a new spray bar because the slit was wrong. If I remember right, it sure looked like that one of yours.
The slit in mine is very hard to see. I thought about taking picture but it's so small, I don't think it would show up.
If you can get the low speed disc, it may run just fine. I figure they only sell it with the remote needle which means buying the remote needle assy. also.
Looks like you can still get the original low speed disc.
The slit in mine is very hard to see. I thought about taking picture but it's so small, I don't think it would show up.
If you can get the low speed disc, it may run just fine. I figure they only sell it with the remote needle which means buying the remote needle assy. also.
Looks like you can still get the original low speed disc.