K&B 3.5 outboard
03-21-2007, 11:23 PM
#52
RE: K&B 3.5 outboard
Here's the most common starting stand you'll see around for the outboards.
I drew one up in Painbrush. It won't have any dimensions on it, but it's simple enough to measure up your boat for what the width should be for across the bunk rails, and it should be long enough to cover the length of the sponsons.
The rails should be a nice soft pine maybe 3" wide x 3/4" thick, however long the sponsons are, and should be measured well so the boat is nice and snug when put on the rails.
Some guys go narrower with the center to center rail width, and cover the top and down the outer sides a little with each rail using air conditioner sealing foam tape, but this usually has to be glued...the pre-adhesive side won't really stick well to bare wood. It will help keep scuffs off the paint, but can be a hassle to keep down.
The 3/4" is only to help get the drilled pilot holes centered enough so its safe enough not to mis-judge your marks and drill through the side.
The wood screws should be flat heads, and they should fit below flush a little so they don't snag on anything. A drill and a countersink bit will be necessary, or a combination bit if your lucky to have one for the screw size.
It's also a good idea to go with the longest wood screws you can find or feel comfortable with drilling, for side to side strength of the rails.
The two cross blocks in red can be put in if you like, they do add support for the rails. It's easy to make a mistake when lifting the boat after it's started and hook a rail with the sponsons, and bend the sides or crack a glue joint.
The Skeg cut-out will have to be hand-saw or bandsaw. Probably the hardest part to get right about this, but it's important the movements stay out of the motor, to relieve strain on the steering servo, and less jumping around with the starter.
When you are happy with the way things fit, knock it down and then add glue and screw it back together again. Mark things so you dont mix up the ends or the sides, and have a mistake after gluing.
This starting stand won't be legal I don't think if you bring it to any races. The sanctions require a box be built around the prop for safety reasons in case a prop comes loose and wants to go flying, and keeps fingers out.
I drew one up in Painbrush. It won't have any dimensions on it, but it's simple enough to measure up your boat for what the width should be for across the bunk rails, and it should be long enough to cover the length of the sponsons.
The rails should be a nice soft pine maybe 3" wide x 3/4" thick, however long the sponsons are, and should be measured well so the boat is nice and snug when put on the rails.
Some guys go narrower with the center to center rail width, and cover the top and down the outer sides a little with each rail using air conditioner sealing foam tape, but this usually has to be glued...the pre-adhesive side won't really stick well to bare wood. It will help keep scuffs off the paint, but can be a hassle to keep down.
The 3/4" is only to help get the drilled pilot holes centered enough so its safe enough not to mis-judge your marks and drill through the side.
The wood screws should be flat heads, and they should fit below flush a little so they don't snag on anything. A drill and a countersink bit will be necessary, or a combination bit if your lucky to have one for the screw size.
It's also a good idea to go with the longest wood screws you can find or feel comfortable with drilling, for side to side strength of the rails.
The two cross blocks in red can be put in if you like, they do add support for the rails. It's easy to make a mistake when lifting the boat after it's started and hook a rail with the sponsons, and bend the sides or crack a glue joint.
The Skeg cut-out will have to be hand-saw or bandsaw. Probably the hardest part to get right about this, but it's important the movements stay out of the motor, to relieve strain on the steering servo, and less jumping around with the starter.
When you are happy with the way things fit, knock it down and then add glue and screw it back together again. Mark things so you dont mix up the ends or the sides, and have a mistake after gluing.
This starting stand won't be legal I don't think if you bring it to any races. The sanctions require a box be built around the prop for safety reasons in case a prop comes loose and wants to go flying, and keeps fingers out.
03-23-2007, 03:16 AM
#53
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RE: K&B 3.5 outboard
hey guys heres some photos of my old K&B with a bit of added extras. i have just added a air cooled head can muffler (until i get the irwin pipe for it) and an ops carby.
hope you guys like im going to test it this weekend at our next race day.
hope you guys like im going to test it this weekend at our next race day.
03-23-2007, 03:33 AM
#54
RE: K&B 3.5 outboard
Another nice one
I got an OPS carb I was going to try too, how does yours work so far? I know they are bigger.
That finned head is the first one like it I've seen, where did you pick that one up at?
I'm glad to see this thread working, I've been sitting alone with my tunnel and motor wondering what everyone else has been up to.
Good luck at the races!
I got an OPS carb I was going to try too, how does yours work so far? I know they are bigger.
That finned head is the first one like it I've seen, where did you pick that one up at?
I'm glad to see this thread working, I've been sitting alone with my tunnel and motor wondering what everyone else has been up to.
Good luck at the races!
03-23-2007, 03:36 AM
#55
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RE: K&B 3.5 outboard
jet pack i havent run the carb yet but i fired it up this arvo for a bench run and boy dose she sound cranky! i did a bearing a the last meet and had to pull it all apart so i decided to change things. lol 
the head is an old k&b car head.
brian from xcell here in aus has a few of them laying around so i decided to try it and see what it dose.
the head is an old k&b car head.brian from xcell here in aus has a few of them laying around so i decided to try it and see what it dose.
03-24-2007, 12:05 AM
#56
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RE: K&B 3.5 outboard
Made a little progress this evening, the top side is done, I think Im gonna add some white to the bottom as tunnels do flip and the solid red will be a little hard for other boaters to see......Also gonna shoot some automotive clear over it for added fuel protection! getting sick of sanding so after the bottom is done with the white im building a new radio box for it as the old one is, well, old and crusty!LOL
Tip for lettering---- sewing thread taped to each end of the hull serves as a straight line, just get it where you want it, peal off your letters and stick them to your xacto knife blade and eyeball the little suckers into place, dont press them down till all lettering is done, when your happy with the way it looks snatch up a good clean soft sock and a hair dryer heat and press, work from center out no bubbles that way and the heat will stick them down good also molds them to any curves or edges you may have...... I do my deacls the same way except dip them in soap and water so they can be adjusted into place...
Tip for lettering---- sewing thread taped to each end of the hull serves as a straight line, just get it where you want it, peal off your letters and stick them to your xacto knife blade and eyeball the little suckers into place, dont press them down till all lettering is done, when your happy with the way it looks snatch up a good clean soft sock and a hair dryer heat and press, work from center out no bubbles that way and the heat will stick them down good also molds them to any curves or edges you may have...... I do my deacls the same way except dip them in soap and water so they can be adjusted into place...
03-24-2007, 12:12 AM
#57
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RE: K&B 3.5 outboard
That looks Great Mike !!! Geez you got a different boat project every month I am to the point where I cant afford to keep up with what I wanna do.
Paul
I am to the point where I cant afford to keep up with what I wanna do.Paul
03-24-2007, 02:47 AM
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RE: K&B 3.5 outboard
you know I bought this tunnel thinking I would just run it as-is, But I couldnt stand it and had to tear into it for a compleate re-do...
03-25-2007, 11:11 PM
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RE: K&B 3.5 outboard
Radio box is built new control rods,throttle cable, seals, servos mounted. its got a wood top instead of plexiglass gives a cleaner look in my opinion..... Also cleared coated the tunnel today LOL still havent done the cowl yet! Figure I would get the hull done and all RTR first...kinda backwards some would even say lazy but Im tired of sanding!!!LOL here is a picture of the new VS. old radio box..
03-25-2007, 11:32 PM
#60
RE: K&B 3.5 outboard
I have an old never used 1/4 scale servo I'm going to drop in mine, and use a one-sided tiller arm. Im thinking of using a carbon tube for that, and RPM brand stainless link balls. I figure it should be plenty sturdy, and no geometry problems, one less boot, and no length problems when going to tilt the motor, just re-center the servo.
I had experienced servo binding with the two arm setup, because the geometry was off between the width of the steering arm, and the narrowness of the servo arm. Unequal length thing as it went through its arc. I kind of got around it by making my own "servo saver" like how a throttle over-run is set up with collars and springs.
Radio box looks nice, good woodworking there. Nice and beefy rails too. You did good by doubling up the middle rails.
I had experienced servo binding with the two arm setup, because the geometry was off between the width of the steering arm, and the narrowness of the servo arm. Unequal length thing as it went through its arc. I kind of got around it by making my own "servo saver" like how a throttle over-run is set up with collars and springs.
Radio box looks nice, good woodworking there. Nice and beefy rails too. You did good by doubling up the middle rails.
03-25-2007, 11:57 PM
#61
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RE: K&B 3.5 outboard
The idea you have for the steering should work, only problem I see you ever having is if you hit something and knock the ball end loose from the engine its going out of control as all steering will be lost and the throttle will also be out of control as the engine will be free to move on its own......since your going with a 1/4 servo you might think about adding a weak spring to one side of the engine that way if it does come loose it will kick the outboard to one side and do circles till it goes over or runs out of fuel....
Im just using the same set-up idea on steering as the boat came to me...4-40 rod 2 from box and two from outboard with wheel collars setting the 4 rods together, easy to move if adjustments are needed....I looked at a cable set-up that a guy at the club has and it looked good, very light, and served the purpose well, But looked like a problem waiting to happen...
Im just using the same set-up idea on steering as the boat came to me...4-40 rod 2 from box and two from outboard with wheel collars setting the 4 rods together, easy to move if adjustments are needed....I looked at a cable set-up that a guy at the club has and it looked good, very light, and served the purpose well, But looked like a problem waiting to happen...
03-26-2007, 12:52 AM
#62
RE: K&B 3.5 outboard
I plowed into a sunken railroad tie one time full blast. I didn't know was there and the water level had dropped.
It ripped all four threaded insert straight out of the transom. I had changed from running solid rods to the the cables setup to try and get away from the servo bind.
It tore off one side of my motor arm, and the only thing holding the motor to the boat was the other cable, and the throttle sheath that was clamped to the case bolt standoff.
I also had one side of my rods fail (collar/spring setup at the servo arm slipped) and learned a loose motor likes to propwalk the motor over into the mount so hard it sinks into the bracket aluminum.
I've run buggies long enough to learn how well ball sockets hold up, and thinking this might be a solution so I'm going to test it out. I seen some guy on eBay selling these motor safety cables where one end gets bolted to an open lug hole and the other to a transom bolt. I almost bought one and even asked if they were all stainless, but the eyelettes that he used on the cable were #6 holes...too big for a 4-40 through the lug.
I'll probably just use a safety cable, but chinch the one end through the lug, and go to a single added doubler with bolt in the hull.
It ripped all four threaded insert straight out of the transom. I had changed from running solid rods to the the cables setup to try and get away from the servo bind.
It tore off one side of my motor arm, and the only thing holding the motor to the boat was the other cable, and the throttle sheath that was clamped to the case bolt standoff.
I also had one side of my rods fail (collar/spring setup at the servo arm slipped) and learned a loose motor likes to propwalk the motor over into the mount so hard it sinks into the bracket aluminum.
I've run buggies long enough to learn how well ball sockets hold up, and thinking this might be a solution so I'm going to test it out. I seen some guy on eBay selling these motor safety cables where one end gets bolted to an open lug hole and the other to a transom bolt. I almost bought one and even asked if they were all stainless, but the eyelettes that he used on the cable were #6 holes...too big for a 4-40 through the lug.
I'll probably just use a safety cable, but chinch the one end through the lug, and go to a single added doubler with bolt in the hull.
03-26-2007, 01:48 PM
#63
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RE: K&B 3.5 outboard
got a question for the motor heads. JUst took off the h2o jacket of a gold carb 3.5 and the inner cylinder sleve moved while i took off the head. It has little slot cut into the flange and i was wondering if that is an indexing tab that needs pointing in a certain direction. Any info ?
03-26-2007, 02:05 PM
#64
RE: K&B 3.5 outboard
Those notches are sometimes accurate at lining up the ports, sometimes I've seen them point to nowhere.
On my K/B SS Air-Cooled motor, the notch should be pointing right at the tapped hole directly over the exhaust port - but still is off a tiny bit when you look at the sleeve location through the exhaust.
Mine still needs to be pointed a little better than the notch is telling me so it is in-line to the casting hole. Not much of a difference, but it not perfect.
If you ever take your motor all the way down, next time check it out...but for now you should be ok.
Usually, the notch is suppose to line up with one of the holes, and on mine it's the one over the exhaust.
On my K/B SS Air-Cooled motor, the notch should be pointing right at the tapped hole directly over the exhaust port - but still is off a tiny bit when you look at the sleeve location through the exhaust.
Mine still needs to be pointed a little better than the notch is telling me so it is in-line to the casting hole. Not much of a difference, but it not perfect.
If you ever take your motor all the way down, next time check it out...but for now you should be ok.
Usually, the notch is suppose to line up with one of the holes, and on mine it's the one over the exhaust.
03-26-2007, 11:37 PM
#65
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RE: K&B 3.5 outboard
I line up the exhaust port as i dont trust the notch... Engine isnt bolted up just hanging there gonna let the clear set for another day or two....Itchin to get the cowl done!!!!! I need paint ideas for the cowl, should i go all red? red with white stripes on the sidestward the bottom? red with white stripe on the top commint to a point in front to kinda match the hull white?? toss out some ideas guys...
03-30-2007, 01:17 AM
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RE: K&B 3.5 outboard
done except the clear coat on the cowl building a battery pack to fit the radio box and cutting down reciever antenna to attach the deans slimline ant. and running it!!! Oh and still need to build a stand for it
04-01-2007, 09:34 PM
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RE: K&B 3.5 outboard
Runs GREAT Im hooked on tunnels!!! I have driven monos cats hydros ECT. The tunnel there is more going on you actually have to drive them and love the way it takes the corners lays down for them at full speed then hopps right back up in the straights!!
