Compression builds as the engine rpm rises, so it may be an issue. You could try the oil sealing test. Get a small plastic tube, like a WD-40 nozzle, and get about five or six drops of oil at the top edge of the piston so it goes against the ring (go through the sparkplug hole, don't just squeeze oil in there, doesn't do the job), let it seal the rings on those two cylinders, then start her and see how she feels. This will raise the compression on the two cylinders temporarily, but won't do anything if it is the valves themselves. If it does make her run better, try a can of Engine Restore, which I have used on a couple old engines in the past to improve the compression/ring sealing.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.