VF90A 4 STROKE.

larrymcauley · Posted: Mon Mar 18, 2024 3:13 pm Post subject: VF90A 4 STROKE.

I bought a 1999 C-DORY 22 CRUISER. Came with 1 60hp Susuki . I replaced it last year with a brand new 90 hp Yamaha.
Went out on SF Bay a few times. Ran well. Still less than 10 Hrs on motor. Last time out was Dec 2023. In January I tried to start motor. It cranks and cranks, fires up and runs for a couple of seconds and then dies. Changed both fuel filters, checked fuel lines. getting gas. Removed injector rail, getting fuel there. New plugs. Put gas supply line directly into 5 gals. of new fuel. Cranks and runs smoothly for 10 secs and dies again. I have done this repeatedly, but still same result.
I watched a Youtube with an Australian guy who seemed to have similar problem. He replaced the IAC Valve and cured the problem.
The VF90A has a ISC VALVE.
This motor is still under warranty.
Any ideas?

Schuster · Posted: Mon Mar 18, 2024 3:41 pm Post subject:

Sometimes it is cheaper to just take it to the shop and have them plug it in to identify the problem. Might have saved you buying new filters and plugs. I suspect it is some electronic sensor that is giving the motor signal to shut down. How long is the initial break in oil supposed to be run. I may be that you have to change the oil. Just throwing it out there as a possibility. Good luck.

colbysmith · Posted: Mon Mar 18, 2024 4:04 pm Post subject:

If it's under warranty, I wouldn't touch it. Take it back to the shop and let them fix it.

larrymcauley · Posted: Mon Mar 18, 2024 6:16 pm Post subject:

Will check oil.
I was hoping it might be something simple I could fix myself and avoid having to haul the boat out and drive across the bridge which is a real pain.

thataway · Posted: Mon Mar 18, 2024 10:27 pm Post subject:

In California you can only buy ethanol laced fuel. Although rare, it is possible that ethanol / water contamination is an issue. Agree take it to the dealer now--get it looked at.

Do you have a Racor Filter in the fuel line? If so, has it been replaced. Also there can be obstruction to fuel flow on the pickup--did you try to switch tanks.

Is the fuel bulb full when the engine does not run.

starcrafttom · Posted: Tue Mar 19, 2024 11:24 pm Post subject:

Is it peeing water? you did not say and that could be the cause. not sure if yamaha has self shut down or not. sounds like its starving for gas other wise. if its getting air in the lines around the bulbs that could cause it to quit.