Briggs and Stratton Vanguard V Twin

[eggsarascal]

Machine started running rough yesterday, lumpy as if only running on one cylinder. Took the plugs out for a look and ones got a lot more carbon build up than the other. What's caused this?, ta.

 

 

[openspaceman]

17 minutes ago, eggsarascal said:

Machine started running rough yesterday, lumpy as if only running on one cylinder. Took the plugs out for a look and ones got a lot more carbon build up than the other. What's caused this?, ta.

 

 

Left hand one has been running over hot, maybe weak mixture, right hand one is carboned  but not oily  so rich, why I cannot guess. When it is running pul one plug cap off to see which one is missing.

[Dan Maynard]

I was trying to figure out whether a weak spark caused the fouling or the fouling with carbon caused the weak spark.
Either way I'd start with checks and easy things. New plugs, check air filter clean, check plug lead condition, check fuel filter.

[eggsarascal]

Two new plugs in, I had them, leads look ok, air filter fairly clean, not bad, fuel filter looks ok. It's running ok with the new plugs, I'm just wondering what caused it to happen.

 

Edit: missed a bit, pulled one plug lead at a time and it ran ok on 1 on each cylinder.

Edited April 22, 2019 by eggsarascal

[openspaceman]

1 hour ago, eggsarascal said:

Two new plugs in, I had them, leads look ok, air filter fairly clean, not bad, fuel filter looks ok. It's running ok with the new plugs, I'm just wondering what caused it to happen.

 

Edit: missed a bit, pulled one plug lead at a time and it ran ok on 1 on each cylinder.

Well chances are it was one of the plugs was duff, probably the black one. There is still likely to be an overheating problem.

 

 

[eggsarascal]

1 hour ago, openspaceman said:

Well chances are it was one of the plugs was duff, probably the black one. There is still likely to be an overheating problem.

 

 

Ok, I'll get it looked at, I know a man that can.

[PeteB]

Plug on left looks okay to me! Is it the carb version or efi?

[eggsarascal]

41 minutes ago, PeteB said:

Plug on left looks okay to me! Is it the carb version or efi?

Carb.

[Dan Maynard]

Could just be duff plug and that's the end of it, they do fail sometimes. Had em go bad when hot too so engine starts fine then plays up when warm.

If it's running fine then maybe after a few hours pull the plugs and just check it's not going black again.

[woody paul]

The spark plug is a service item and should be changed after so many hours.