problems with 2006 4.3 mercruiser

[stanleylee128]

I bought a 2007 four winns 180 with a 4.3 mercruiser turn key start carby motor 190 hp. It only has 30 hours on it. First I found 2 bend valves on the left side head, so had it removed, repaired and bolt back on. Check compression, all good. It was running fine until the temperture alarm goes off when it gone pass 3500 revs. Once I back off, the temp was good again. The motor runs fine when cold but idle very rough when hot. Also notice a flat spot under 2000 rpm. I clean the carby twice already and is still running rough. So there are 2 problems, idle rough when hot and overheating on hi revs..........Any idea would be appreciated. Thanks.

 

[Bondo]

Re: problems with 2006 4.3 mercruiser

Ayuh,... Welcome Aboard,....
Standard operating procedure for an Overheat situation is to change the Impeller,+ possibly it's housing 1st...

Head on up to the Adults Only section of this forum,...
There you'll find factory manuals for your motor,+ drive, alone with related topics on diagnosing your problems...

 

[Don S]

Re: problems with 2006 4.3 mercruiser

Have you checked the timing in base timing mode, and also checked the advance timing while in normal mode? How were the valves bent? or were the tuleped?

 

[Fun Times]

Re: problems with 2006 4.3 mercruiser

WOW almost hard to believe the engine was in that bad of shape, Did you check the fuel to see if it's Bad, old, water, ect???

What is the history of this boat?

Got a engine serial number?