1989175xp

[cfw]

this motor has less than 100 hrs and it filled the #5 cyl spark plug with alumiun. there is slag on top of the #5 piston, no cylinder wall problems and it still has compression. I was running about 60 when it backfired and shut down, What happened and should I put a new plug in it or what?

 

[jonesg]

Re: 1989175xp

wow, that might have been detonation, it will be interesting to read what the experts say. I wouldn't run it.
That aluminum came from somewhere, its either piston or head metal.

 

[tashasdaddy]

Re: 1989175xp

pull the head and find out what happened. do not run it.

 

[emdsapmgr]

Re: 1989175xp

Did it lock up when it quit? What does the plug look like? It may be running lean. I'd pull the carb that feeds that cylinder and have a look at all three jets on that side of the carb that feeds that bad cyl. You should pull the intake side cover off and look at the side of the piston also. Post what you find out.

 

[cfw]

Re: 1989175xp

the plug filled with alumnium. did not lock up ,I ran on 5 cyl. after that all day.
oil in # 5 cyl, cyl not scored,still has comp.,top of piston has alumnium slag on it, no burnt piston. weird deal because I was in a bass tr at the time and still fished all day no torgue out of hole but still could run 50mph

 

[Dhadley]

Re: 1989175xp

The top of the piston is burned. It'll be some sort of ignition related cause. What spark plugs are in it?

 

[cfw]

Re: 1989175xp

champion l77jc4 all other plugs and cylinders look real good , so does this mean I have to change out the piston? thx