yamaha f4msh

[Tacomalife89]

Hello I have a Yamaha 4hp 4 stroke that I just got from my father. I got it home and got the motor to run but I have one problem. Once at idle and I turn the choke off after about 30 seconds the motor wants to rev up if I pull the choke out and push it back in really quick it idles normal again for a bit and then revs back up has anyone seen this before or know what could cause this? Thank you in advance

[zenoahphobic]

Fuel starvation, the engine runs too lean.
Check carb drain screw to see what comes out. Probably needs a thorough fuel system clean.

[ausnoelm]

Yep, blocked carb or an air leak, or fuel supply from tank, pretty common symptoms.

[Tacomalife89]

Yep, blocked carb or an air leak, or fuel supply from tank, pretty common symptoms.

Thank you I’m going to try and find a air leak somewhere only because I have took the carbs apart and everything I have seen looks good so far to me Sharon thank you guys

[ausnoelm]

Chances are you didn't clean the carb properly, Yamaha carbs are notoriously difficult to get clean, all passages MUST be cleaned out, washing or spraying won't clean them.

[panasonic]

Any idea what year it may be? Should be a tags on the transom bracket with full model and year on it.

If it is the set up I am thinking about it has a u shaped plastic intake manifold with 3 or 4 gaskets on it. They all have to be in place and seated properly so there is no air leaks present.