Scota4570

On main crank bearings, ie chainsaw conversions, should I remove one seal or both? If i remove only the interior one, on nthe bearing, what lubes the rubber oil seal? Is it better to have double insurance against crankcase leaks? Would adding some oil between the bearing and exterior rubber seal be sufficient?

I have one engine that had a sqeuaky tight rubber seal for quite a while. I think the drag affected the idle making a slow stable idle harder to achieve.

w8ye

My Feedback: (16)

Leave the outer seals intact. Run the engine for a couple hours and the seals will loosen up.

Be careful with the bearings. There are "U" and "UU" siffix bearings that have special seals

If a two stroke crankcase has an air leak, it will never run.

Scota4570

I tore into the problem engine, an echo 65cc conversion. I removed the rear oil seal and cut off the rear crank extension. I then made a plug to fit in the hole. Surprizingly the hole was 1 3/8". I think a freeze plug for and auto engine block might work great if one does not have a lathe to make one. I also added a gasket between the crankcase halves. That loosened a slight bind on the beaings. Well, it tuns much easier. It now idles way down to 1400 reliably.