stuartbowen

Hey guys Iam having a lot of trouble with one of my kb 3.5cc gold ss engines. I know that the hs needle on the stock gold carb should be 2.5-4.5 turns out but my boat keeps acting really lean and I am around 6 turns out and it is still acting lean. I started at 3.5 and continually richened up but it does not seem to be changing. Also the idle is really higheven though the carb is maybe1/16 to 3/32 open.Also,I tried to kill it by covering up the carb with my finger and it would not die.Dont know ifall theinfo is relevant, just thought idprovide as much info as possible.Does anyone have any ideas on what to do?
Current Setup
Engine-Stock
Plug- Os A5
Prop-Prather 215 or 220
Fuel-SIG 55/19 boat

Ron Olson

My Feedback: (1)

You've probably got a big air leak somewhere, I'm guessing around a bearing. 3-1/2 turns out on the carb should be a good setting. Check for junk around the needle also or damage to it. Might be blockage somewhere in the fuel system, a kinked tube in the tank maybe that's limiting flow.
Got a pressurized fuel setup? Had to ask.

stuartbowen

Other than from exhaust to tank I do not have anything pressurizing.  I checked earlier to see if anything was blocked or kinked and I could not find anything wrong with the tank or line.  I was thinking air leak also from past experiences on cars but I know some stuff is differnent so I had to ask.  The boat btw is a VILLAIN and it is completely the stock set-up as for tank (sullivan) and servos ect. My only thought was that maybe the o-ring that goes between the carb and the actual engine is not tight enough, but noticed earlier it was not really visibly squeezing between the two.  However, I could not see a gap anywhere so is there any way to see if there is air leaking around it?  I know there is no tank or line air leak thought.

ob nut

My Feedback: (1)

had a problem couple of years ago where my SS would run 3/4 throttle. Any more and it would die. This even at 5+ turns out. Motor was sent to Rod G. to have the motor looked over since I could not find an issue. Rod found a problem with the crank housing. Motor has been running fine..

It's the small cracks you can't find.. Take a good look at the case and crank housing for tiny cracks.

Can't help on the needle settings as I've started to use BM flow meter. Found out that not all needles are the same. Good area to start would be around 4 turns out. Can't speak of the plug you are using, but a MC9 will work with the 55% fuel you are using.

icedude1989

just my small worth, check between engine and exhaust (manifold), check the engine cooling seating on top of the engine, and the carb o-ring. i have a kyosho sunstorm and i was having the same problem with it. it turned out to be i was leaking air from on top of the chamber. between the cooling and the engine itself.
good luck with finding your problem.

dave

Ron Olson

My Feedback: (1)

Is that the SS motor? Those things can be a pain in the rear, had one. They have ot be run slobbering rich. I also blocked off the hole in the exhaust as that block was originally set up for an exhaust throttle but they only closed off one hole.
Sometimes things like that will drive you nuts trying to chase down the problem. It's harder doing it over the 'net so all I can do is throw some things at you to check.

RickeyRockstar

My Feedback: (4)

These motors run great if the fuel delivery system has no leaks zip tie all fuel lines from the muffler (to provide perssure to the gas tank) as well as pick up this motor should be running top at 3 turns with 20% nitro what size prop are you running? use a hot plug (Maye a #3) or something short with no idle bar try that
Rick in Denver

ob nut

My Feedback: (1)

Also, check the bearings (top and PTO).. If bad, they can cause air leaks.


RR.. The SS needs a long plug.....

jmy2u

Definately sounds like an air leak,first thing I would check is all the case bolts including the ones holding on the PTO. If those are OK the remove the PTO and check the bearings, they are notorious for causing a lean condition when bad.If you have checked everything else then it could be the the main engine bearings.

jetpack

My Feedback: (1)

The two holes holding the carb on sometimes are tapped oversize and allows air to slip past under the carb. These are not deep threads, and air only has a couple spirals to take to slip in past the mixture.

You would think they would machine a groove lower down in the neck to put the O-ring in instead of just under the body of the carb. There's usually enough wall thickness to do it.