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Engine temp/tuning questions...

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Old 03-29-2006, 06:18 PM
  #1
nitrosteve22
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Default Engine temp/tuning questions...

Ok... Today it is about low 60's (maybe even high 50's) and I think I'm close to where I need to be but some things just kinda baffle me here. Now I constantly read that most .12-.18's will run on average 220F-250F with %20-%25 fuel but then I also read NOT to tune an engine to run with in a set temperature guideline. Now I'm running Trinity Monster Horsepower %20 fuel (sound ok or should I switch?) and I think the HSN is pretty much good to go,maybe a hair richer but it puffs a good trail of smoke when you get on and stay on it but at idle it still spits what I would consider a fair to little amount of fuel out the exhaust but if left in one spot it will make a tiny puddle so I'm assuming my LSN is to rich? The idle is a bit high to (see carb opening pic and tell me how it looks).

Heres what gets to me,I ran it around and it got to some high temps but after I ran through one tank till outta gas and I let it cool down to 170F and then fired it back up and let it sit and idle for as long as it needed to figure out where it would stop rising. Well it likes to sit right around 250F-254F and QUICKLY jumps to 270F-290F when you get on it (took it out to the street to open it up) which kicks in my fail safe stopping the throttle servo (not to be confused with the problems I've been having with the throttle servo) and all I read says that a small block shouldnt be running that hot,a lean tune would cause that but I can tell you right now it AINT lean! I get a what seems to be a good 8-10 (maybe more) minutes out of a full tank,plenty of run time? It'll idle as long as you let it without stalling and the RPM's stay smooth (although a little high IMO).

How can it be running this hot but still spit more than what I would call normal amounts of fuel out the exhaust @ idle & low RPMs but leave a healthy trail when gas is applied on what I consider a pretty cool day??????? Gets even worse when the bodies on... I swear the more tuning threads I read the more confused and irritated I get. Does it sound like I need to lean the LSN out and start to worry when temps reach 300F or does it sound like this mill just likes to run on the hot side? It has plenty of punch from idle to WOT and doesnt stall or bog at all. Although I need to loosen the shift screw cause I couldnt get in to second gear (not worried about that though lol).

Thanks guys!
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Old 03-29-2006, 07:42 PM
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Default RE: Engine temp/tuning questions...

I would richen it a hair. Your car wont sit and idle(or shouldn't) for a long period of time.
That carb opening looks pretty good by the pic, but what I would also be concerned about is the amount of dirt around it. It looks to me that there is even some dirt in the opening of the carb...
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Old 03-29-2006, 07:53 PM
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Default RE: Engine temp/tuning questions...

richen it a little on the high end, 1/8 turn then run it for like 30 seconds and check temp again. make sure the cooling fins on the head are clean, the carb looks dirty so maybe the head is caked up a little too. its not abnormal for a car to spit out oil on idle or idle then take off.
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Old 03-29-2006, 08:09 PM
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Default RE: Engine temp/tuning questions...

Steve,

Don't worry about the oil its very normal. You would have to look at a plane after a good flight. The muffler side of the plane is usually greasier than a fry pan from bacon! I had an OS CZ-R in my Stinger and just beat that thing to death and it allways ran. I used to get it going on the top end till the slight crackle sound was gone but no leaner, allways ran good. It was always fun when it was just about to run out of fuel you would hear it scream and just be waiting to see what flew out the engine !! Never blew though.
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Old 03-29-2006, 08:17 PM
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Default RE: Engine temp/tuning questions...

if you richen it, the idle may drop a little too so i wouldnt fool with the idle yet. If you pinch the fuel line and the idle revs high and then the engine dies your low end need to be leaned a little, if it idles and reve a little or not at all your low end is fine. this is for the idle only, does not effect the running of the engine at higher speeds. you engine is a little hot at 290 but if it runs good and has smoke coming out and spittin fuel at idle maybe its fine. also if you run in wide open for a few seconds does it die or bog down, sometimes this is a sign of a lean engine.
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Old 03-29-2006, 10:06 PM
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Default RE: Engine temp/tuning questions...

Well,I'm starting to think there might be a leak somewhere. I unscrewed the HSN and its damn near flush with the sleeve and still jets up to 290F,got it to 302F once but only for a split second. It does idle up when I pinch the line so I'll lean the LSN out a little. I cant believe how dirty this thing gets and how fast it gets their! But holy sweet christ on a crutch is this thing fast! and accelerates like a rocket! It wasnt getting dirt in the carb,its just the rough surface of the materials of the carb,I checked good and the air filters are cleaner the closer to the carb (and I dont run without em). It doesnt bog or die either.

So could it be a leak?

Thanks.
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Old 03-29-2006, 10:20 PM
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Default RE: Engine temp/tuning questions...

i would suggest cleaning it up, then start it up and spray some carb cleaner around the base of the carb and see if the idle changes, this could be a leak spot. if it does then maybe it needs to be removed and maybe resealed. Make sure you check the temp at the top of the cylinder where the glow plug goes, this is the best place to get a true reading.
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Old 03-30-2006, 03:05 AM
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Default RE: Engine temp/tuning questions...

So I spent a good two hours taking everything apart for cleaning and inspection. Did a bunch of tweaking and re-doing stuff so hopefully this should fix the heat issues. Either the engine had a leak somewhere or it just likes to run hot. I've unscrewed the HSN till its almost flush with the sleeve,get plenty of smoke but still running hot just not quite as bad so I'm hoping this fixed it or atleast helped. Only thing I didnt take apart was the HSN sleeve assembly but I reseated the carb and pullstart. Checked the headbolts and they are plenty tight with no leak spots although there was alot of dirty dirt caked on around the carb (see pics). Where I run the buggy next to the large parking lot is alot of dirt/gravel and rocks seem to get stuck in the wheels easily,bent a rear dogbone (anyone know what size of CVD's will fit this thing F&R?). And I keep my venoms temp probe on very snugg at the bottom cooling fin like the instructions show. Got a bunch of tanks in today as the weather was good! Plenty of power,as the buggy can easily get out of control on loose surfaces. All gears are good and intact although the diff's feel a little dry but I'll get some good grease to pack em with on friday.

My old neighbor caught me out playin with my Tornado and I think he got bit by the RC bug so I cant imagine it'll be to long before he's out there racing with me,but he wants the Volcano. He had never seen a nitro burner before and was blown away by the speed and power,excited like a 5 year old on christmas morning .
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Old 03-30-2006, 08:15 PM
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Default RE: Engine temp/tuning questions...

hey just a quick pick ur brain question? but how exactly do you tune the carb up, i mean which way on the HSN and the LSN do you turn to richen or lean it out,

i have the 1/10th HIMOTO SYCLONE .18 thanks andy

or if uts easier just pm me thanks agian
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Old 03-30-2006, 09:53 PM
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Default RE: Engine temp/tuning questions...

This question is all over the forums. In case you didn't find it yet, clockwise lean, counter clockwise rich. Good luck . You will get the hang of it in no time.
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Old 03-30-2006, 09:54 PM
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Default RE: Engine temp/tuning questions...

Unscrew-counterclock wise= richen
screwing in-clockwise= leaning

I'm not sure what the starting point would be as the instructions arent clear but I think I unscrewed the high speed needle till it was flush with the sleeve,and screwed the low speed needle in all the way and backed it out like 3 turns or so and left the idle where it is in the pic above.

Edit: Denis beat me to it
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