40hp mariner 676b 411306 carb problems (1980's)

[bob williams]

My mariner is giving me fits, it's on a pontoon and runs fine on low speed, but when I nail it it blubbers and misses. Most of the it will clean out then run fine to full throttle. I have had the carb cleaned twice. It ran better with the air box off, and a little better yet with the cowling off. That tells me something is restricting the air flow. The manual choke is disconnected, leaving only the elec. choke. Can ayone help me before I turn it into an anchor

 

[clanton]

Re: 40hp mariner 676b 411306 carb problems (1980's)

Check needle and seat, set float, I have seen some engines blow powerhead gasket, fill engine cover with exhaust and smoke engine starves for air.