9.8 2 stroke slowly fouling and stalling

[xort]

My Tohatsu 9.8B 2 stroke runs fine when first started. But after maybe 2 minutes slowly looses idle speed until stall. Plugs are very wet after stalling. I've shot carb cleaner thru and adjusted the mix screw with no success. Checked plug gap, OK. I dry out the plugs and let it sit for a few hours and it starts up OK but stalls after a few minutes again.

I'm in the Bahamas so internet is very slow making downloads of info difficult. Unfortunately, I didn't buy the shop manual before I left. Mistake.

Before heading to a repair shop, looking for suggestions. I'm not sure I want to pull the carb to clean it without a manual or a rebuild kit. Is this easy? Any cautions? Suggestions?

Thank you,
Ed

 

[pvanv]

Re: 9.8 2 stroke slowly fouling and stalling

Ed,

Your float may be a little too high, allowing a too-rich condition. Pull the carb and verify the float height (should be parallel to the casting when inverted). otherwise, you may need a new float needle (valve). Either way, you sound too rich, and the float valve needs to shut off sooner in order to keep the proper mixture running to the cylinders.

R U Ed from Seven Seas sailing?

 

[xort]

Re: 9.8 2 stroke slowly fouling and stalling

Hi Paul

Thanks for the suggestion.
Is this carb tricky to work on? I'd hate to have some easily broken part put an end to my work. Replacement parts may be hard to get here. There are signs of gas under the carb. Not sure if the filter or lines that are leaking or if it's from the carb.

Today I tried to start it and it would run fast for about 5 seconds and quit. That's new.

I don't think I'm the Ed you are thinking of. We did talk about pulling my mast but Irene sent me west to Chicago instead.

 

[pvanv]

Re: 9.8 2 stroke slowly fouling and stalling

The carb is very straightforward. Of course, a really ham-fisted mechanic can wreck even the most indestructible unit, but if you have reasonable ability, decent tools, and a Factory service manual to use as a guide, you should be OK. If the carb has never been gone through, it wouldn't hurt to get a carb kit: Part # 369871221M, $52.06, available from any dealer, including me.

 

[xort]

Re: 9.8 2 stroke slowly fouling and stalling

Wish it was that easy...we're in the Bahamas now. Shoulda woulda coulda!

 

[xort]

Re: 9.8 2 stroke slowly fouling and stalling

Paul

I think your float suggestion was the trick. The float was maybe 5 degrees off level. I gently bent it level. Also, the fuel hoses were wet so I replaced the clips with clamps. Pulled the needle, it was clean. Blew compressed air into the seat. That's all I could see to do. Cleaned it up and re assembled. seems to run well now. idled for a long time and then ran it with no stalling. Will run it longer tomorrow.

Thanks much!

 

[pvanv]

Re: 9.8 2 stroke slowly fouling and stalling

Sounds like you may have gotten it. Also... Be sure to always run the carb out at the end of each and every day to reduce any varnishing in the future.

 

[xort]

Re: 9.8 2 stroke slowly fouling and stalling

So far, it looks like I fixed the problem.

But I have a new one! I'm seeing fuel dripping under the bowl. My suspicion is the rubber gasket that seals the bowl to the carb or the seal on the fuel pump. In the short run, I don't have access to a rebuild kit. What can I use on that rubber seal to help it seal tightly? Silicone grease?

 

[Sea Rider]

Re: 9.8 2 stroke slowly fouling and stalling

That gasket is already compressed, dried out and will not seat properly any more no matter how tight you adjust bowl's screws, need a new one ASAP or engine could catch fire real soon...

Happy Boating