7.5KB tuning issues

[Chris Dixon]

My brother n law and I are having a hard time tuning a 7.5 K&B outboard. It doesnt have a K&B mixer carb. He cant get it to idol very well and it is difficult to tune it to run at full throttle. He replaced the fuel tubing and we think it could be getting air in the fuel from possibly the fule tank. Could it be the humidity cause it terrible here lately. Any suggestion ?

 

[RodneyPierce]

Chris, can you post a picture by chance? And they wont idle well usually. They load up easily and die. Have to keep it cleaned out or at a little bit higher idle then one would be used to, on say a buggy or truggy.

And is it laying over at full throttle? Or dieing out? If so, its likely lean. I would richen the needle up. A good starting point seems to be 3.5-4 turns out on the needle from just snug.

But Im kind of curious when you say it "doesnt have a KB mixer carb"?

 

[Chris Dixon]

some of the Kb carbs has the mixing disc on the carb....I will get u a pic as soon as possible

 

[RodneyPierce]

I think I get you. Its still got a high speed needle though. Is it dieing at full throttle? If so, richen the needle.

 

[Scott Wadlow]

sounds lean... or maybe the prop is to big....what prop and Pics will help

 

[RonShaw]

There are so many things that could be wrong. Tank not sealed, fittings, trash in carb, carb not sealed at case, bad bearings in engine or pto, lean needle, etc. The case could even be cracked which plagued many of those motors.

You guys want to come up to Wake Forest one day, or I could drive to your site to help you one weekend that I am in Little River. Just let me know. I would be glad to help you out.

 

[Chris Dixon]

There could be so many things wrong. Tank not sealed, fittings, trash in carb, carb not sealed at case, bad bearings in engine or pto, lean needle, etc. The case could even be cracked which plagued many of those motors.

You guys want to come up to Wake Forest one day, or I could drive to your site to help you one weekend that I am in Little River. Just let me know. I would be glad to help you out.

thanks might just do that

 

[john schultheis]

I had the same problem on the last outboard i set up the prop was to big so i dropped down a few sizes and it runs great now

 

[Carl Van Houten]

I would take Ron's offer to help you. That will keep you from getting frustrated with it.

-Carl

 

[Chris Dixon]

I would take Ron's offer to help you. That will keep you from getting frustrated with it.

-Carl

thanks Ive spoke to ron on the phone.