2007 Mercruiser 4.3L mpi start then stalls

[hex290]

Hello guys! this is my issue. I have a 2007 290 DA with twin 4.3/ Bravo 3, this issue happened to me last summer 1 time and it happened again last week, after everything runs good, sit and a cove for 4-5 hours my starboard engine will start for 5-6 seconds but it won't pass 500 rpm and then stalls, on those 5 or 6 seconds I tried to rev the engine but it does nothing, you can't even tell any difference, after running on one engine for 3-4 minutes (because I got to go back to the marina one way or the other) it will start normally and runs as smooth as it always did. Like I said is really annoying and so far only happened twice in 1 year exactly, I hope you guys can help me get this fix, thanks!

 

[stg099]

if you give throttle only to that engine, maybe 1/2 throttle will it start and run? If so, IAC valve needs replaced. If not, it sounds like it could be vapor lock in the fuel system. Is this happening when it's hot out? are you running the blowers while underway and for a bit after shutdown?

 

[hex290]

if you give throttle only to that engine, maybe 1/2 throttle will it start and run? If so, IAC valve needs replaced. If not, it sounds like it could be vapor lock in the fuel system. Is this happening when it's hot out? are you running the blowers while underway and for a bit after shutdown?

Even with throttle won't start, temperature was around 80's , I always run the blower before starting and on idle like no wake zones etc, what's the IAC valve? Thanks!

 

[stg099]

Even with throttle won't start, temperature was around 80's , I always run the blower before starting and on idle like no wake zones etc, what's the IAC valve? Thanks!

Idle Air Control valve. Typically if you can start with throttle but the engine won't idle this is the likely culprit, but that does not seem to be the case in your situation.

 

[hex290]

Idle Air Control valve. Typically if you can start with throttle but the engine won't idle this is the likely culprit, but that does not seem to be the case in your situation.

correct, after a research about the IAC the symptoms don't match, my engine starts right up but stays around 400-450 rpm for few seconds and using the throttle won't do anything.