yamaha 4 stroke cold start problem

[Capt dave 258]

I have a 2001, 80hp, Yamaha carbureted 4 stroke that will not start when the engine is cold. I have to give it a shot of starting fluid at the beginning of the day to get it running. It will start fine the rest of the day. I had the carbs cleaned last year by a mechanic. The motor has 2 cold start valves attached to two of the carbs. I tested them by adding 12 volts and they close as they should. I've read that the seals/o-rings may go bad on the valve body. I have a set on order, though mine look fine and I don't believe that's the issue. I ran a 12 volt test light to the wires that supply the valves and it does not light up when the ignition is on. I'm assuming that I am not getting power to the valves for them to operate. I traced the wires back and they clip onto a small, plastic box that also has two other wiring harnesses plugged into it. Any ideas as to how to do further testing to correct the cold start issue? Thanks

 

[99yam40]

does the needle move slowly when you put 12V to it, or fast like a solinoid being energized?
if it is slow moving ,it should get the voltage from the motor battery charging system while the motor is running.
if it moves fast maybe you have to push in the keyswitch or another switch to operate it like a choke while starting

being called primestart assembly I would think it is the slow moving one.
extra fuel would flow when motor and prime start assembly are cold and shuts off as they heat up.
your problem is it is letting the extra fuel thru while cold.
you will have to find out why.
maybe something is plugged up or put together wrong.
did it start and run fine after you mechanic cleaned the carbs?

also what is your cold starting procedure you follow?
you should not be opening the throttle to let more air in

 

[Capt dave 258]

does the needle move slowly when you put 12V to it, or fast like a solinoid being energized?
if it is slow moving ,it should get the voltage from the motor battery charging system while the motor is running.
if it moves fast maybe you have to push in the keyswitch or another switch to operate it like a choke while starting

being called primestart assembly I would think it is the slow moving one.
extra fuel would flow when motor and prime start assembly are cold and shuts off as they heat up.
your problem is it is letting the extra fuel thru while cold.
you will have to find out why.
maybe something is plugged up or put together wrong.
did it start and run fine after you mechanic cleaned the carbs?

also what is your cold starting procedure you follow?
you should not be opening the throttle to let more air in

The needle moves slowly when energized. Good to know that it only gets power when running. I checked with the key in the on position and it did not get power. First chance I get, I will start it up and ensure power is to the solenoid. I have tried several starting methods, including just priming the gas bulb and turning the key, priming the bulb and giving it throttle several times, neither worked. I bought the boat last year knowing it needed the carbs cleaned. Since the mechanic did so, I don't recall it ever starting easily. I've seen a video where a mechanic said the solenoids rarely go bad and it's more likely the o-rings between the solenoid body and carb. I have new o-rings on order and hope that solves the issue. Thanks for your input. If you have any other thoughts, please let me know.

 

[99yam40]

if the motor will not start cold, the only problem I can think of is no extra fuel is flowing.
that has nothing to do with the prime start heaters ( they are not solenoids)
they just close of the extra fuel when warmed up

 

[Capt dave 258]

Above is the video on cold start issues with Yamaha's. My apologies on calling them solenoids. I believe the term is cold start valves. I have removed both and tested them and the needle moves slowly as it should when warming up. According to the video, that closes off the additional fuel needed upon startup. My issue is that I am not getting enough fuel upon initial startup and/or too much air, hence the need to give the carbs a shot of starting fluid. The o-rings between the valve body and the side of the carb look to be in fine condition and are pliable. The video shows the possibility of another air leak between the carbs and manifold, once again caused by bad o-rings. I had the motor running today on muffs (using starting fluid) and sprayed carb cleaner around the carb to manifold area to see if the rpm's would increase, indicating a leak, but the rpm's stayed the same. All fuel lines look to be in good shape and the primer ball gets hard upon squeezing. I'm still trying to figure this out and am looking for ideas/thoughts. Thanks

 

[99yam40]

you need to check to make sure fuel can flow thru those passages, and figure out how 2 of them can put extra fuel into 4 cylinders.
some passage is plugged up or someone put it back together wrong maybe.

did those orings get replaced when the carbs were cleaned last year?

 

[boscoe99]

Have you removed the Primestart valve body and cleaned it in an ultrasonic cleaner?

 

[cyclops222]

Did the engine start easily BEFORE the mechanic worked on the carbs ?????