2005 5.0 mpi hunting/surge at idle (cold only) Mercruiser

[nauticool]

Hi, had this problem for a while but seems to be getting worse.

It used to be when I started from cold the engine would hunt at idle between 500rpm and 700rpm and now it will barely run unless I start with the throttle slightly advanced, shouldn't have to do this with fuel injection I know.

Once warm it will happily idle at 600rpm.

I can live with this problem but worry it could lead to something else plus when it comes to selling this would not be a good feature!

Any suggestions greatfully received

 

[muc]

Re: 2005 5.0 mpi hunting/surge at idle (cold only) Mercruiser

Might want to check your IAC muffler. They can get plugged up and cause this problem.
It would be best to do something --- if muffler plugs up it will wear out the IAC faster.
Good Luck Muc

 

[nauticool]

Re: 2005 5.0 mpi hunting/surge at idle (cold only) Mercruiser

The muffler is clean like new, despite the engine being 5yrs old it's only done 90hrs.
After reading a few forums it sounds like the iac may need replacing. It looks like a simple enough part, does anyone know if they are complicated to fit?

Thanks guys!

 

[burp]

Re: 2005 5.0 mpi hunting/surge at idle (cold only) Mercruiser

One electrical connector, 2 screws and a gasket...... IAC costs around $110.

 

[nauticool]

Re: 2005 5.0 mpi hunting/surge at idle (cold only) Mercruiser

Sounds ok then, anything else it could be or to check before buying/fitting one?

Thanks!