6.2l mercruiser alarm reduce revs

[butchely]

Was travelling along at 3500 rpm for 10mins and the gauge read reduce speed (engine ran fine). I reduced the revs to idle for around 5 mins and switched the engine off (still running fine). Went to start it again and it ran really rough. Two days later engine still starts but is running like it is on 4 cylinders out of 8. The engine is a 2005 6.2 efi 383ci any ideas thanks.

Butch

 

[Bondo]

Re: 6.2l mercruiser alarm reduce revs

Ayuh,... Welcome Aboard...

What have you done for diagnosis,..??

 

[butchely]

Re: 6.2l mercruiser alarm reduce revs

Basically checked oil for water and gauges for any fault messages.

 

[JustJason]

Re: 6.2l mercruiser alarm reduce revs

Your engine is in gaurdian mode. It keeps the rpms down to help keep the thing from blowing itself up.

It could be....

1. cooling water pressure (depending on the setup)
2. engine cooling water temp
3. exhaust temp
4. oil pressure

Or you may have a fault in the efi system. You really need a marine scan tool and the service manual and an understanding of both to DIY.

 

[butchely]

Re: 6.2l mercruiser alarm reduce revs

Got a mate to take a look at it today and we found a broken valve spring. We had a heart attack when there was no comp in the last cylinder we tested. Whats a spring worth?

 

[QC]

Re: 6.2l mercruiser alarm reduce revs

You will be VERY lucky if all that is wrong is a broken spring. The thing to think about is what was that valve doing without the spring to hold it up?

 

[Snobike Mike]

Re: 6.2l mercruiser alarm reduce revs

Whats a spring worth?

Springs are cheap.

It's the most likely bent valve, marred valve seats and pistons that will be the expensive stuff.

Good luck.

 

[butchely]

Re: 6.2l mercruiser alarm reduce revs

The valve still moves freely up and down so we might be lucky.