3.0 LX Mercruiser Sputters and Dies

Brad S

Petty Officer 3rd Class
Joined
Nov 22, 2008
Messages
84
I have a Mercruiser 3.0LX
Engine Serial #OD 428548
Digital Distributorless Ignition.
At idle it does not miss. When moving at 1500 rpm's can feel the motor miss (sometimes). When giving it more throttle it continues to miss more and gets to about 2000 rpm's and sometimes backfires. If I give it more throttle about 2500 rpm's it dies. Is this an ignition problem and if so where do I start or is this a carburetor problem. Was told this could be a coil problem. If so, is there a way to test the coil? Also told bad was told could be bad wires or bad plugs.
Has new plugs - AC-MR 43LTS. with gap of .035" as called for on top - of the air cleaner.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 3.0 LX Mercruiser Sputters and Dies

The backfiring makes it sound like a carb problem.
Do you have a water separating fuel filter? If not, might want to install one.
Have you replaced or checked the fuel filters in the fuel pump and carb?
 

Brad S

Petty Officer 3rd Class
Joined
Nov 22, 2008
Messages
84
Re: 3.0 LX Mercruiser Sputters and Dies

Yes on the water separating fuel filter
Will check on the filters
 

fat fanny

Lieutenant Commander
Joined
Feb 9, 2006
Messages
1,935
Re: 3.0 LX Mercruiser Sputters and Dies

Go through the entire fuel system check the fuel filter at the end of the fuel line connected to the carb and the filter in the bowl of the fuel pump then ensure there are no blockages in the fuel line from the tank including the vent which could be part of the fill cap and the anti siphon valve which is most likely sscrewed to the tank as part of the barb for the fuel line connection for blockage and ensure it moves freely. This is a start and it costs nothin unless you need a filter if this doesn't test out move onto you ignition system I'm not familar with the DDS ignition system to aid at this time look up in the adults only stickies at the top of the forum for some info. Good luck and post back!
 
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