Yamaha f40 hard to start

[Disschord]

Hi I have a 2008 Yamaha f40 bet 67C L 1041598

The engine is hard to start and takes me about 5 mins + to start (turning over 5 seconds at a time and leaving 30 seconds between trying) but once startered it will run rough for a few minutes dying a few times but then once warm runs fine and performs normally under load.

The carbs have been ultrasonic cleaned and fuel pump replaced and new priming bulb and fuel line.

The only other symptom I have is that when I prime the engine after a few minutes the bulb will be soft and will take a few more pumps and again if I wait I am able to make a few pumps and so on.

[boscoe99]

Try turning the idle mixture screws outwards about half a turn and see if the situation improves.

Is the Primestart device set to the automatic position? Try the ON position and see if that improves things.

Try advance the throttle rapidly and then return it to idle. Wait a bit and advance it quickly again. Do this three times. Does it improve the situation?

Were the carburetors synchronized after they were cleaned? Were all passageways confirmed to be free and clear of any swarf or swill?

[pstephens46]

Swarf and swill includes bumble bees.....

[TownsendsFJR1300]

Sounds like your choke /enrichment system isn't working..

[boscoe99]

Swarf and swill includes bumble bees.....

It does.

No bees please for meees.

[Disschord]

Try turning the idle mixture screws outwards about half a turn and see if the situation improves.

Is the Primestart device set to the automatic position? Try the ON position and see if that improves things.

Try advance the throttle rapidly and then return it to idle. Wait a bit and advance it quickly again. Do this three times. Does it improve the situation?

Were the carburetors synchronized after they were cleaned? Were all passageways confirmed to be free and clear of any swarf or swill?

How do I set the prime start to auto? How do I set the prime start to on?

The carbs have been vacum balanced

[boscoe99]

Sounds like your choke /enrichment system isn't working..

Could be. Particularly if once upon a time it started quickly and ran with no problems.

But of all the rotten carburetors in all of the Yamaha world the one used on the OP's motor is the rottenest one of all. Yamaha changed from a #40 jet to a #38 jet and a large number of the motors will barely run at all.

[boscoe99]

How do I set the prime start to auto? How do I set the prime start to on?

The carbs have been vacum balanced

My bad. Your carburetor does not have an override position in the event of a failed Primestart fuel enrichment device. Some do. Some don't.

[Disschord]

Could be. Particularly if once upon a time it started quickly and ran with no problems.

But of all the rotten carburetors in all of the Yamaha world the one used on the OP's motor is the rottenest one of all. Yamaha changed from a #40 jet to a #38 jet and a large number of the motors will barely run at all.

Do you think changing my jet help?

Is it the pilot jet or main jet?