Fouling spark plugs
08-16-2009 | 09:05 AM
#11
Banned
Joined: Oct 2006
Posts: 5,844
Likes: 0
From: Bradenton Florida
I have the same problem , only on #3 cyl. I found it !!!!
The oilring on the piston is not sealing,so the leakdown/compression test does not show damage !!!
Only @ idle a little oil gets in to the chamber and the spark will not burn it off,,,mine is not smoking either and the oil loss is so minimal that u can't tell.
Thats whats wrong with mine,,,on yours ,could be a lose valveguide,ripped valveseal also.
Changing heatrange ,,,,NO !!! But don't use these plugs ,,YES. Go to NGK BR6FS !!!!!!!!!!
After u fixed it.
The oilring on the piston is not sealing,so the leakdown/compression test does not show damage !!!
Only @ idle a little oil gets in to the chamber and the spark will not burn it off,,,mine is not smoking either and the oil loss is so minimal that u can't tell.
Thats whats wrong with mine,,,on yours ,could be a lose valveguide,ripped valveseal also.
Changing heatrange ,,,,NO !!! But don't use these plugs ,,YES. Go to NGK BR6FS !!!!!!!!!!
After u fixed it.
08-17-2009 | 02:17 PM
#12
Gold Member
Joined: May 2002
Posts: 1,127
Likes: 0
From: DFW
Enforcer, have you solved the problem ? If not, how many hours are on the engine ? Had you ever had the carb off ? (rags or restriction in intake) Have you checked valve lash?
What is oil pressure @ idle and run ?
It sounds like your valve trane may be a problem.....Week lifters, valve lash, flat cam, rockers.
Let us know what you find when you find it, Please.
What is oil pressure @ idle and run ?
It sounds like your valve trane may be a problem.....Week lifters, valve lash, flat cam, rockers.
Let us know what you find when you find it, Please.
08-19-2009 | 08:04 PM
#14
Platinum Member
Joined: Jul 2008
Posts: 931
Likes: 0
From: Little River SC
Hi guys I have got a on going problem for a year now with no answer or any ideas left. My starboard engine (454) is dry (carbon) fouling spark plugs in cyl. 7 and 8. It will foul MR43T's in minutes MR44T's in hours. However it seems that if I am hard on the throttle it is not near as bad, if I cruise at 3500 RPM they're toast. I have changed the rotor, cap, wires, and coil. I checked my compression and its fine. I swaped my carbs thinking I was over fueling no good. I have no oil loss and no smoke from the engine. The thing will misfire and run like crap I will replace those two plugs (7&8) It will run like a raped ape then I slowly loose rpm's till it misfires I'll replace those plugs and go like hell again. By the way It has a prestolite ignition. Any help would be great. Thanks, Barry.
