88 marathon w/robin 2 cycle

[jimwalter]

Need some help. My 88 marathon is sputtering and misfireing. I have replaced the coil, plug and wire, still gas same problem. Any ideas??

[Sean5545]

Can you describe the problem a little better? Only when hot? When cold? High speed? Low speed? All the time? Etc

[Sean5545]

Also it's a robin 2pg engine?

[cart around]

You may want to take your fuel pump apart to look for a ripped lower diaphragm.

Once you give more detailed information, we will be able to narrow it down.

[jimwalter]

As soon as it's running, robin 2pg, pointless ignition

[jimwalter]

Also, using electric fuel pump

[Sean5545]

Did you replace the fuel pump because the old stopped pumping or some other reason? I ask because lower engine compression is responsible for making the original fuel pump work, if it stopped it may have been bad compression as opposed to bad pump. What was done with the hole in the top of the ending where the old fuel pump was?

[JohnnyG67]

I had the same issue with my 2pg, and after chasing down a few things I realized I was fouling plugs (or at least I thought because I had just done the top end) but they were black and sooty, not oily, which made me think weak spark. Turns out my voltage regulator was bad and so it was draining the battery trying to provide spark. The more the batt. drained, the less spark quality, leading to sputtering,backfiring and me thinking the plug was fouled. 1 new regulator later, charging nicely now, and haven't had the issue return at all. Just one more thing to check and not a real expensive part. I had noticed one of the 4ga. wires going to the starter/gen. had been rubbing on the regulator and exposed some copper and was probably what caused the regulator to fry in the first place.

[jimwalter]

Sean5545, it had elect. pump when I bought the cart. The hole on block is plugged and sealed, no air leak. I completely rebuilt the engine 6 years ago..

[jimwalter]

JohnnyG, good info had not considered the regulator. Been too long of a time working on something with one. I will check regulator operation later today and cables. Where did you find a regulator? I have an engine upgrade just about ready to install but still have a few things to finalize for that so I need the buggy to keep chugging for now. I'm installing a kawasaki TIA400SIB snow sled engine.