Yamaha 50 fuel enrich problem

J

Jeremy Burne

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Joined
Dec 4, 2009
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2
Hi All, I'm new here from Australia and would like some help with my Yamaha 50 1999 model. I have a problem with cold starts and thought my "fuel enrich solenoid " was faulty. I removed the solenoid and applied 12v across it expecting it to click or at least pull the needle in. it did nothing so I bought a new one and the new one does just the same!! I was wondering what voltage is required to activate the solenoid. There is continuity through the solenoid [the old one].
 
Dunaruna

Dunaruna

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Joined
May 2, 2003
Messages
6,027
Re: Yamaha 50 fuel enrich problem

If you are talking about the electrothermal valve, it does not click. Measure the piston height, apply 12v and wait a few minutes, measure the piston height again. You can also do a resistance check , 2.3 - 3.5 ohms is within specs.

Do you have a genuine manual?
 
J

Jeremy Burne

Recruit
Joined
Dec 4, 2009
Messages
2
Re: Yamaha 50 fuel enrich problem

Hi Dunaruna,
Thanks for the info. I hooked up the new " prime start assy " as Yamaha call it and it did slowly extend over a few minutes. Does it extend to make the mixture richer for cold start or the opposite? When starting from cold should I get 12v to the valve? The engine starts well when using the red emergency choke lever on the side of the air intake. No I don't have a manual.

Thanks Jeremy
 
Dunaruna

Dunaruna

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Joined
May 2, 2003
Messages
6,027
Re: Yamaha 50 fuel enrich problem

It slowly extends to close off the primestart feature. It is, in effect, an automatic choke. Yours is working o/k.

If you need to use the emergency start lever, that usually indicates a problem with the idle circuits in the carbs, time for a carb rebuild/cleanout.

You have a PM.
 
9

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,880
Re: Yamaha 50 fuel enrich problem

Do a search for prime start to find more info about how it works
 
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