f40 yamaha,dirty carbs.

[handle]

I have a yamaha 06 F40 TLR with dirty carbs. Last year had them cleaned twice. Ran good after second cleaning for remainder of year. Started up this spring, runs poorly and has every spring on startup. I use stabil and even put it to bed last year with non ethanol fuel , to no avail. The mechanic suggested putting larger pilot jets in ; referance that they lean out the motors to meet epa standards. I have treated all gas and have a 10 micron filter,USCG Shields fuel line. Tried to cover all the bases but this ethanol fuel I believe is beating me up. I know the carbs are tricky but at the cost of cleanings and recurrence of the problem I think it's time to tackle this job. Advise!

 

[robert graham]

Re: f40 yamaha,dirty carbs.

That's a lot of time, trouble and money! The only thing that I can think of that you could do more, is to start draining your carbs a few times a year, and especially during long motor lay-ups. Maybe the fuel line between your 10 Micron Filter and the carbs is deteriorating and fouling the carbs? Is it genuine Yamaha Marine Fuel Line?

 

[handle]

Re: f40 yamaha,dirty carbs.

This motor package was all set up by the dealer, so I assume from the micron filter to the motor is gen yamaha material, but I agree on degradation possibilties of that said hose. I have not yet cut a piece of it open to see how it looks; nor have I checked out the small inline filter inside the motor yet. In research I have found out those simlar carbs on the 30hp have larger pilot jets. Just maybe the f40's pilot jets are to small to handle any build up of sediment what so ever. Runs wide open great if you can get it there. Searching for any and all ideas!