1980 9.9 Johnson sputter at full throttle

[Barfass79]

Hi All, Since I received very good help with my last post, I am posting again! This time to figure out the issue at full throttle with my 1980 9.9 Johnson. When at full throttle the engine will sputter (sounds like when you put your 2 lips together a blow) A while ago I was out with a bunch of buddies and had the thing conk out on one cylinder, thus starting a very long ride home. I believed it to be a coil obviously but wanted to redo the carb as well, so the carb was redone with new Jets, packing, float and gaskets etc. That was a while ago and when I took it out last it was doing the sputtering thing. It will go in and out of its sputter giving me full power for a couple of seconds and then go right back into it. Any ideas guys/gals?

 

[JB]

Re: 1980 9.9 Johnson sputter at full throttle

Sounds like your engine is "4 cycling", Barfass. It is running just a tad too rich on the high speed circuit.

Did you change the size of the high speed jet?
Is the float level set according to the book?

I don't remember if that engine has an adjustable HS jet, but if it does, turn her in about half a turn..

Good luck.