225 efi missfire

[pioneer17]

i have a 1999 225 merc efi motor suddenly started to missfire especially in gear it will hardly run noticed it was shooting a lot of gas out of exhast. any ideas what could be the problem

 

[Don S]

Re: 225 efi missfire

Have you checked the fuel filters for water? Did you check for spark on all 6 cylinders?

 

[pioneer17]

Re: 225 efi missfire

checked for spark and all six are sparking . could this be a timing problem

 

[Don S]

Re: 225 efi missfire

checked for spark and all six are sparking . could this be a timing problem

I doubt it. Unless you messed with the timing, it probably didn't change or is not causing your problem. You also have an efi engine. LOTS more things to go wrong.

 

[pioneer17]

Re: 225 efi missfire

tried runing i again still missing even though all plugs are sparking . Wheni try to take off motor reves up good 5800 rms tries to take off , then suddenly looses all power any more ideas

 

[Don S]

Re: 225 efi missfire

You only answered the last half of my first question.

 

[flabum]

Re: 225 efi missfire

Do the basics first. do a compression test, check for water in the fuel, replace the spark plugs.

 

[pioneer17]

Re: 225 efi missfire

found no water in filters did comp check all 6 are 92-94 psi.

 

[Don S]

Re: 225 efi missfire

110 should be the minimum compression. So you are 16 to 18 psi below minimum. Assuming you did the compression test properly, that isn't going to be a good running motor no matter what you do to the fuel or ignition.