7.5 o/b PROBLEMS

[lakeracer]

I just acquired a used 7.5 outboard K&B on an Aeromarine Predator. I ran it today for a little while. When you crank it up it sprays fuel everywhere. It runs down the side of motor and out of the carb. What do you guys think, I have very little knowledge on nitro engines(always have had electric). Also, it does not run good at all. I adjusted carb to K&B instructions and it will not rev good when its in the water, in return does not run but maybe 15mph. What have I done wrong?

[Ron Olson]

That might be part of your problem, it's way too rich. The K&B owners manual has the carb settings way too rich. Take the needle all the way in then bring it out about 3-1/2 turns then dial it in from there. Nitro percentage, prop, weather and a list of other things can make your boat run poorly.

[lakeracer]

That might be part of your problem, it's way too rich. The K&B owners manual has the carb settings way too rich. Take the needle all the way in then bring it out about 3-1/2 turns then dial it in from there. Nitro percentage, prop, weather and a list of other things can make your boat run poorly.

Needle valve was 2 1/2 turns out and pouring fuel out of carb. Could something be wrong in the motor causing the fuel problem.

[Ron Olson]

It depends on which carb that you have. It's possible that if you have one with the low speed needle on it that it could be too rich. It'll be the screw inside of the throttle arm or a disc on the newer ones.

[lakeracer]

Ron,
My carb has the disc on the side should I try leaning it out more than the factory setting?

[Ron Olson]

You can mess with it a little. The screw should be in the middle of the slot normally.
I never did like those carbs, my now ex-brother-in-law had one on his 'rigger and it was nothing but trouble for him. That tiny screw would come off easily from vibration and the barrel would then slide out. He had the barrel split in half on it too. If you can, you might want to find an older 7.5 carb for it or the "Red" carb, they're much better.

[lakeracer]

Ron,
Thanks for all your help, I will be purchasing one.

Thanks,
Lakeracer

[peter_joh1978]

I know it was awhile ago, but two things you could have tried. The spray bar inside the carb needs to be facing down towards the crank and the carb needs to be opened w/ the servo in a counterclockwise rotation. If you go to the mecoa website the instuctions explaining all of this are there.