25hp 4 stroke tohatsu struggling

noboatsmarts

Recruit
Thread starter
Joined
Jun 26, 2009
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3
Hi all. I'm trying to get my boat ready for the family fishing trip and can't keep it running. I admittedly don't know much about engines, but can enlist the help of my father-in-law if we can just get pointed in the right direction.

I have a 2003 25hp 4 stroke tohatsu outboard. Every year I replace the plugs (appropriately gapped), change the oil/filter, and give it a fresh tank of gas with Sea Foam additive to get things started. This year is no different except that I used a Fram oil filter instead of a Wix and can't get it to stay running unless I stay on the throttle.

It doesn't sound terrible, but when I raise the RPMs it seems to belch intermittently. That's the best way I can explain it. It will purr for a minute then start letting out intermittent "brrrurrrps". When I back off the throttle to let it idle it instantly dies. Any ideas as to what's going wrong?
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,587
Re: 25hp 4 stroke tohatsu struggling

I believe you have an MFS25A. Time to clean the carbs. All three of them.
 

Wee Hooker

Chief Petty Officer
Joined
Sep 11, 2005
Messages
618
Re: 25hp 4 stroke tohatsu struggling

If you don't have time to clean the carbs properly (i.e your trip is NOW) try putting a triple dose of seafoam in the fuel and run it up/down for a good hour or two. It may not cure it but may make it livable for the short term. OF course, if you have the time, do it right!
 

noboatsmarts

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Jun 26, 2009
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Re: 25hp 4 stroke tohatsu struggling

Thanks for the advice. Looks like I'll be busy today!
 
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