2001 mercruiser 350 mag efi overheat and stops

[intwoit]

I have a 2001 mercruiser on a JC pontoon boat. The engine is EFI and is a 350 mag. I have 2 problems with it.

1. Engine overheats after about 30 minutes and shuts down. The temp guage reads 180 degrees, but no HI temp buzzer. After about 20 minutes it will restart.

2. The engine will shut down when run at 3000 rpm for 10 minutes. I can restart and will run again, as soon as I reach 3000 rpm again it will quit after about 2 miutes.

My mechanic thinks I am crazy, but I can not seem to get it fixed. wife is very frustrated.

Thanks,
Al

 

[Don S]

Re: 2001 mercruiser 350 mag efi overheat and stops

Hook up a diagnostic computer and find out which sensor is showing a fault that is causing the problem.

 

[intwoit]

Re: 2001 mercruiser 350 mag efi overheat and stops

I assume the boat mechanic did this, although probably not while on the river. Can you put a diagnostic device on the motor while on the water?
Thanks,
Al