250XXL EFI saltwater problem

[prolinesport]

My 250xxl started running rough. Figured time to tune,had been 5 years. Marina changed plugs and water filters. No codes, perfect compression. 1st time out ,ran great for an hour ,shut it off to fish and after that was hard starting poor idle and loss of power. Marina checked, no codesbut had fouled plugs. So they put another set of plugs in it. Seems weird to me that they think changing plugs again will solve problem. Have not been back on boat yet.Just got invoice again and another $580. Not only that but the second set of plugs are Champions instead of OE NGK.
Have not called yet , trying to cool off. HELP .

 

[alldodge]

I have no issue with Champion but others do, same as a Ford Chevy thing

Fouling plugs is its running rich. Changing the plugs will get it running good again for a little while and they to will probably foul out. Could just clean the plugs and it would run good for a while.

Need to find out why the plugs are fouling. Need to check fuel pressure, it might be high. If its not high then check the MAP readings to see if its within limits.

If the motor thinks is cold (ECT sensor) then it will keep giving it more fuel.

 

[prolinesport]

I have no issue with Champion but others do, same as a Ford Chevy thing

Fouling plugs is its running rich. Changing the plugs will get it running good again for a little while and they to will probably foul out. Could just clean the plugs and it would run good for a while.

Need to find out why the plugs are fouling. Need to check fuel pressure, it might be high. If its not high then check the MAP readings to see if its within limits.

If the motor thinks is cold (ECT sensor) then it will keep giving it more fuel.

Thank You