yamaha 2004 40hp 4 stroke

[bellavista803]

Im considering purchasing a dingy with a 40 hp 2004 yamaha 4 stroke triple carbs
Any problems with these engines especially carbs????

[99yam40]

Re: yamaha 2004 40hp 4 stroke

I have heard they have very small passages and clog easily
Also hard to sync

[bellavista803]

Re: yamaha 2004 40hp 4 stroke

I have heard they have very small passages and clog easily
Also hard to sync

thanks much appreciated

[boscoe99]

Re: yamaha 2004 40hp 4 stroke

The carburetors in a Yam F40 are particularly problematic.

If you buy the motor, and if you have carburetor problems, remember the Yamaha F25. If F25 jets are installed in an F40 that won't run worth a darn, those F25 jets will make it seem like a new motor. Virtually all of the carburetor issues will be over. Just keep clean fresh fuel in the motor. Drain the carb bowls if it is going to sit idle for a while.

[bellavista803]

Re: yamaha 2004 40hp 4 stroke

The carburetors in a Yam F40 are particularly problematic.

If you buy the motor, and if you have carburetor problems, remember the Yamaha F25. If F25 jets are installed in an F40 that won't run worth a darn, those F25 jets will make it seem like a new motor. Virtually all of the carburetor issues will be over. Just keep clean fresh fuel in the motor. Drain the carb bowls if it is going to sit idle for a while.

Any idea what it should cost to have the F25 jets installed??

[boscoe99]

Re: yamaha 2004 40hp 4 stroke

Any idea what it should cost to have the F25 jets installed??

Too many variables for me to hazard a guess.

[ChefMercury]

I am having same issue. Just want to make sure I am reading this correctly. So you are saying to replace the jets of an F40 with the jets of an F25 or it has F25 jets and they need to be changed to another size jet?

[boscoe99]

I am having same issue. Just want to make sure I am reading this correctly. So you are saying to replace the jets of an F40 with the jets of an F25 or it has F25 jets and they need to be changed to another size jet?

An F40 comes with jets (3) for an F40. The F25 comes with a jet (1) for an F25.

The F25 jet is larger than the F40 jets.

The installation of the larger F25 jet into the F40 will help to cure carburetor related problems that are somewhat inherent in the F40.

[ChefMercury]

Thank you!!! Would you happen to know the part number of the F25 jets? I would like to order them asap!!