1998 Yamaha F50 fuel enrichtment system how does it work?

[Andersen222]

Hello forum.

as the title says.. I have a 1998 Yamaha F50 with a primestart and a choke solenoid function.
What and how does this system work?
Can anyone explain this to detail?

 

[boscoe99]

Send me your email address and I will provide you with some literature.

 

[Andersen222]

Send me your email address and I will provide you

Hello thank you.
MOD EDIT - Email address removed for your safety. PM bosce99.

picture of the parts on my engine

 

[Andersen222]

Have had trouble finding a service manuel for this engine.
For some reason it’s only the updated version without the choke solenoid from start 00’s

 

[Andersen222]

Also the trouble im having, is when in neutral the engine is slowly increasing the rpm by itself. Im thinking the fuel emrichment system to do this somehow ?

 

[boscoe99]

Have had trouble finding a service manuel for this engine.
For some reason it’s only the updated version without the choke solenoid from start 00’s

 

[boscoe99]

Email sent.

Good luck sorting your problem. That is one hellava complex system.

 

[Andersen222]

If the prime starter assy doesn’t work i could be running way to high idle when the engine is hot, as it won’t extend and open the choke plates?

 

[Andersen222]

Or am i wrong?

 

[robert graham]

The Primestart is a hot wax pellet actuated needle system( very similar to the thermostat on a car)….it is totally automatic and is open when engine is cold, then when engine starts the voltage supplied closes the needle valve. Most Primestart have 3 settings, on, off and automatic(called normal)….if all is well with the system then leave it in the normal position(small red plastic switch on carb)…very dependable fuel enrichening system….

 

[99yam40]

The Primestart is a hot wax pellet actuated needle system( very similar to the thermostat on a car)….it is totally automatic and is open when engine is cold, then when engine starts the voltage supplied closes the needle valve. Most Primestart have 3 settings, on, off and automatic(called normal)….if all is well with the system then leave it in the normal position(small red plastic switch on carb)…very dependable fuel enrichening system….

Robert, this system he has is no where close to what you and I have on our motors.
he needs to read up on what Boscoe sent him

 

[robert graham]

Well, he mentioned something about his “primestart” assembly doesn’t work????

 

[boscoe99]

Primestart is a Yamaha term for any automatic fuel enrichment system. They are not all the same.

Primestart on an EFI F350 or the latest XF425 direct injection model is completely different than Primestart on two stroke models.

 

[boscoe99]

Or am i wrong?

Did you read the literature I sent you or did I just waste my time?

 

[Andersen222]

I got the mail. I was just trying to write how i think it works, after reading your pdf.
just to see if you will agree og disagree

 

[99yam40]

if the choke plates do not open up as the should, you could see that if you looked.
I have no idea how that system works since I never looked at a motor like it or a manual for it

 

[Andersen222]

How long will it take the thermal heater do move the plunger?

the choke solenoid works fine, when starting.

but after 5 mins the plunger have not moved at all

 

[99yam40]

is there voltage to that heater unit while the motor is running?

 

[Andersen222]

Yes there is, measured yesterday

 

[Andersen222]

Just measured again today, it’s only getting 6-7 volts, should it be getting 12 v all the time?

and how must resistance should there be over the thermal heater in proberly working condition?