Kerpit
New member
Hi there
I am seeking some help/opinions on spark plug reading. I'm mainly concerned with the mag side plug which is the one that the base of the plug is only colored 3/4 around. Compared to the pto side it's darker indicating some possible incomplete combustion problems. Both cylinders have 120 psi. This has a psi pipe with 100 pilots turned out 1.5 turns and 147.5 mains. The pics on the bottom are with 110 pilots and 150 mains. Sled runs great except kinda chasing a top end problem. Cleaned clutches and tried a stiffer primary spring and I can get about 70 mph and 7k rpm in 300 yards. Sled idles smoothly, I'm planning on spraying the mag side crank seal with starting fluid tomorrow and rigging up some tooling to pressurize the case. Can anyone shed some light on why the mag side plug base isn't fully coloring???
thank you for your help
110/147.5
this is maybe 5 miles of a mix of idle/full throttle monkeying around
110/150
also misc 5 miles in a field
I am seeking some help/opinions on spark plug reading. I'm mainly concerned with the mag side plug which is the one that the base of the plug is only colored 3/4 around. Compared to the pto side it's darker indicating some possible incomplete combustion problems. Both cylinders have 120 psi. This has a psi pipe with 100 pilots turned out 1.5 turns and 147.5 mains. The pics on the bottom are with 110 pilots and 150 mains. Sled runs great except kinda chasing a top end problem. Cleaned clutches and tried a stiffer primary spring and I can get about 70 mph and 7k rpm in 300 yards. Sled idles smoothly, I'm planning on spraying the mag side crank seal with starting fluid tomorrow and rigging up some tooling to pressurize the case. Can anyone shed some light on why the mag side plug base isn't fully coloring???
thank you for your help
110/147.5
this is maybe 5 miles of a mix of idle/full throttle monkeying around
110/150
also misc 5 miles in a field
780srxgeorge
Member
do you have the air box on it?.if not go a little richer.on the right side
Last edited:
Kerpit
New member
Yea the air box is on it. Even with the 110/150 jets the mag side plug base is only colored 3/4 around...?
780srxgeorge
Member
looking at pic's again i would just run it.thay don't look bad at all.
Kerpit
New member
Just an update on this. I blocked off the exhaust and removed the carburetors. Then installed 1 1/4 pipe with caps to the carb boots. Installed and air fitting on it. Put regulated 10 psi of air pressure to it and then sprayed the engine with gas detection soap. The mag side crank seal was leaking and a few other small leaks at the reed cages.Repaired the leaks and ran the engine today and im now reaching 7200 rpm and the base ring on the plug is fully colored.