Yamaha 1990 225 HP 2st does not start cold

FrenchFry

Seaman
Joined
Nov 13, 2009
Messages
73
This is a follow-up to thread http://forums.iboats.com/showthread.php?t=363524

At the end I said "I think everything is solved" because I was not sure about cold start.

So, same story as in the begining of the thread : if the yellow cable which gives voltage to the computer is connected, the motor does not start cold, if I disconnect it, the motor starts right away, and then waiting a little bit and reconnecting the cable it starts on the normal circuit and runs fine.

I don't get it, what can cause that ? I suspected the prime start system (that I changed some time ago...) and read different threads about it on this forum, but what is the logical between motor starting right away when computer is bypassed and not starting when computer is on ? As far as I understood the prime start is in the open position at start and then the thermo-valve closes it after it started, so what has the computer to do with that at cold start ?

Maybe it has nothing to do with prime start, Rodbolt mentionned the motor had been cobbled, when it was working "correctly" to start it I had to engage the key, pull the acceleration lever at the remote control and then it started, but it is not the way it's supposed to work, I should have been able to sart it without using the acceleration lever, so what could have been done on this motor ?
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yamaha 1990 225 HP 2st does not start cold

goota do some research on that antique.
dont see many but best I recall the enricment valves are solinoids not electrothermals.
means the yellow wires to the a and b valves are always hot at key on and the ECU makes the grounds as nessasary.
but let me look some.
have you tried leaving the ECU bypass wire in place and moving the manual cold start lever?
 

FrenchFry

Seaman
Joined
Nov 13, 2009
Messages
73
Re: Yamaha 1990 225 HP 2st does not start cold

Yes, I have tried, it was the way it started before, while moving the cold start lever it makes a kind of "asphyxia" noise now (bl bl bl...)

See the prime start here : http://infonais.fr/moteur7.jpg

I have tried to use the red lever too, no effect.

I let you check but I don't think it's solenoid, would be interested to know how this prime start works exactly. There should be a logical explaination why it starts right away when the complete system is off and not when it's on.
 
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