Mercruiser 5,7 EFI 1999

[schjoth]

Hello

I have a problem - the engine in my boat runs extremly rich.As of now the boat is virtually useless because of the heavy gasoline odor. It starts fine,idle is ok and WOT is also no problem. I have made a compression test an all cylinders where fine (12-14 bar) The fuel pressure regulator is new and so is the IAC valve and temp sensor.
Today I connected a vacuum gauge. The reading where about 20 in/hg - but not quite steady.What do I do from here?

 

[makomark]

hire somebody with a scan tool or buy one. Other than that, you can only check the items the computer doesn't have any input from or control of. RINDA makes the 'industry standard' for scan tools.

 

[guyjg]

"The reading where about 20 in/hg - but not quite steady.What do I do from here?" May be dirty injectors and sticking valves. Get a can of SeaFoam and put 1/3 of it in the oil, fuel and fuel/water separator. It will smoke alot for awhile. Change the engine oil and filter when it's done smoking.

 

[schjoth]

Okay - thanks for the reply. Is it possible for at sticky valve to create the rich running condition?

 

[guyjg]

No. Choke not working can cause it or poor injector spray pattern caused by worn or dirty injectors. Instead of spraying fuel they will squirt it and the mixture does not atomize, thus a rich mixture forms and won't burn properly.

 

[mongo]

How about a plug reading - may help isolate it to an individual cylinder or two.