1976 40 hp Mariner (built by Yamaha)

boatlab

Recruit
Joined
Mar 12, 2012
Messages
3
I have a 1976 Mariner outboard 40HP. The boat will only run on full choke. Is there a way to adjust the carb, do i needa rebuild. Starts right up in full choke and will run but as soon as i backoff the choke it stalls at any speed.
 

sutor623

Rear Admiral
Joined
May 23, 2011
Messages
4,087
Re: 1976 40 hp Mariner (built by Yamaha)

I have a 1976 Mariner outboard 40HP. The boat will only run on full choke. Is there a way to adjust the carb, do i needa rebuild. Starts right up in full choke and will run but as soon as i backoff the choke it stalls at any speed.

I JUST dealt with this. Either run a heavy mix of seafoam into carb and let it sit for a few mins, or pull the carb. I had some varnish in my main fuel jet in the carb. Once I got rid of it, VOILA!
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: 1976 40 hp Mariner (built by Yamaha)

rebuild the the carb and pump, with new gaskets
 

boatlab

Recruit
Joined
Mar 12, 2012
Messages
3
Re: 1976 40 hp Mariner (built by Yamaha)

I have a 1976 Mariner outboard 40HP. The boat will only run on full choke. Is there a way to adjust the carb, do i needa rebuild. Starts right up in full choke and will run but as soon as i backoff the choke it stalls at any speed.

Thanks guys---when you put the seafoam in did you put it directly into the carb or in the gas and if so how much. If that doesnt work I'll pull it and rebuild. I think iboats has the re-build kit
 

sutor623

Rear Admiral
Joined
May 23, 2011
Messages
4,087
Re: 1976 40 hp Mariner (built by Yamaha)

Thanks guys---when you put the seafoam in did you put it directly into the carb or in the gas and if so how much. If that doesnt work I'll pull it and rebuild. I think iboats has the re-build kit

What I usually do for this is get a 1 gallon gas can, or just full up 1 gallon in your tank, and put 1/2 of a can of seafoam in the gas. It will smoke like hell, but if it just happens to be gunk in the jets, it should clean it out. Run the motor for a min or so with the choke on, and then let it set. Start it up and do this a few times, and it just may dislodge any varnish. It is worth a shot before tearing the carbs down.
 

boatlab

Recruit
Joined
Mar 12, 2012
Messages
3
Re: 1976 40 hp Mariner (built by Yamaha)

What I usually do for this is get a 1 gallon gas can, or just full up 1 gallon in your tank, and put 1/2 of a can of seafoam in the gas. It will smoke like hell, but if it just happens to be gunk in the jets, it should clean it out. Run the motor for a min or so with the choke on, and then let it set. Start it up and do this a few times, and it just may dislodge any varnish. It is worth a shot before tearing the carbs down.

Thanks I'll give it a shot
 

sutor623

Rear Admiral
Joined
May 23, 2011
Messages
4,087
Re: 1976 40 hp Mariner (built by Yamaha)

Thanks I'll give it a shot

If you can get her to run without the choke on, go ahead and run the gallon the rest of the way through her. Make sure to run the motor in a bucket, and set the idle in forward gear, for a final test or itll run great in the driveway, then when its time to hit the water, ya just will never know.
 
Top