Black Scorpion shutting off after x seconds?

[wesblake 8]

Hi all. 2006 Avy, Black Scorpion motor.

Ran great last summer, winterized for a couple months. Brought it back out, de-winterized, did oil change.

Started boat with fake-lake as usual, boat runs for a # of seconds (I would say about 8s, but it seems like it's the same amount each time) then just shuts off. Runs great while running, smooth, and just shuts off like something is telling it too, not like a sputter or something mechanical but more like a signal or as if you just turned the key off.

So, I went through the remainder of the maintenance schedule, new fuel filter, new water separator, and new spark plugs too.

Same thing. Runs great, X seconds, then shuts off. Hooked up Vessel View, no codes.

So, July of 2019 I replace my IAC valve, the boat would die every time I dropped back to idle while moving, or just not idle without a little throttle when first warming up. Fixed the issue. Fast forward back to today, I read on this issue and keep getting IAC valve again! But it's only got a year on it. I saw a "test" to give it throttle in neutral after it starts to see if it stays running that way. It does, over the normal shutdown time, but it goes up and down. Meaning if I set it at 1500rpm, it will slowly fluctuate (over about 3s) between 1200 and 1500, but not shut off. Go back to idle, wait the x seconds, shuts off.

Sound like IAC again? I did buy the cheap one everyone uses form Amazon vs the OEM one. I'm trying to just get this thing going again without an arm and a leg because I'm trying to post it for sale!

Thanks.

[wesblake 8]

So it was suggested I ensure battery is fully charged and charging working first. I put the charger on over night, just tried boat again this morning. Voltage reads 11.9V with engine off, reading 14.4V when it's running, so everything seems fine there.

This time, I timed it while running, 35s first time, then 40s, then 38s so it seems to run 35-40s. Only this time when it shut down the 3rd time it didn't necessarily sound like a quick shutoff, it sort of sputtered off briefly.

Should i order that valve? Any ideas?

I do keep getting some trouble codes when I start up VesselView but I don't think any are relevant to my boat so I've been ignoring them. Inserting in case.

 

[wesblake 8]

Weird, I THINK it was vapor lock. Someone said remove the gas cap and try to run it. It stays running! Hoping it stays this way now.

[Troy. R 198]

I’m glad you figured it out. I had been following this thread, but unfortunately had nothing valuable to add.

[beau t 8]

if removing the cap kept it running did it shut back off when you reinstalled the cap? Im only asking because here we have dirtdobbers that like to build (nest?) in open lines which could be a vent line maybe?