Two Cylinder Cub and two not working

Tue Jun 01, 2004 10:11 am

I have been struggling to get my wife's 52 cub running right. Any attempt to Mow would bog the engine down and kill it dead. I installed the IH carb kit $$, new points, condenser, plugs, pulled the governor completely apart, re-timed the engine, rewired.

After all of that a friend stopped by and said you're not running on all cylinders. Sure enough the two middle cylinders are not hitting, the plugs are firing but you can pull the plug wires off when running and there is no change in the engine. This would explain my no power/bogging problem.

Now I have two suspects Valves or Rings. Any other thoughts before I pull the head and get to work.

PS. What is the compression range per cylinders????


BobbY W
Shreveport LA

Tue Jun 01, 2004 10:19 am


I don't know if this is your problem or not but... your symptoms are the same as they would be if wires #2 and #3 were reversed. Try switching them to see if it helps. A lot easier than tearing the engine down!

switch wires

Tue Jun 01, 2004 10:31 am

Thanks, but I was so hopeful that that was the problem I must have switced those wires 10 times just to make sure...............................

Tue Jun 01, 2004 12:03 pm


O. K., that was hopeful. The next step would be the compression check. The absolute number isn't very important, but it should be in the ballpark of #1 and #4. If they are significantly lower, pull the side cover and see if the exhaust valves may be sticking. If the intake valves stick, it won't run at all.

Tue Jun 01, 2004 12:15 pm

Also bobby, if the compression checks out ok, you can check the intake manifold. The center of the monifold can be leaking causing the center two cylenders to run lean enough not to fire.

Mike Chesser

Tue Jun 01, 2004 2:03 pm

If your compression is low on those cylinders, another factor might be a blown head gasket between those cylinders. Can you see any bubbles in the radiator if you fill it or any water in the oil?