case 300 backfires

Fri Mar 30, 2012 2:22 pm

Would a bad condenser cause a case 300 to miss and backfire? Rebuilt dist was installed and ran for 3-4 hours then started acting up. Tried a new coil but no better. Starts when it's cold but misfires within minutes of running and get's worse as it's runs. Any suggestions? :(

Re: case 300 backfires

Fri Mar 30, 2012 9:15 pm

A condenser can cause it, but so can a worn distributor shaft. check for side play that may be causing the point gap to change while it is running.

Re: case 300 backfires

Sat Mar 31, 2012 5:54 pm

Their is a new/rebuilt dis with new points and condenser in the machine. The motor was rebuilt and has not run right from the get go. Been this way for over a year. I installed the rebuilt dis because the old one had over .050 side play in the shaft and thought I had it solved. No such luck. Ran fine for two hours then started acting up again. That's why I was thinking a bad condenser. :lost:

Re: case 300 backfires

Sat Mar 31, 2012 8:18 pm

Sounds like time to look at valve adjustment and cam timing.

Re: case 300 backfires

Sun Apr 01, 2012 3:49 am

That's not a bad idea. Figured they were out of play as the motor was farmed out to a rebuilder. His reply when first contacted was "it was running fine in our shop". Guess it's time to get back to basics.

Re: case 300 backfires

Sun Apr 01, 2012 7:23 am

Since your distributor is freshly rebuilt, it may have worn in a little and changed the point gap. I think I'd check that first. It could be a bad condenser, though.

Re: case 300 backfires

Fri Apr 13, 2012 1:38 pm

Finally had time to work on the 300. Tried a new coil out of my cub and it still would not run right. Better but something was still wrong. Replaced the cond. and put a new coil on and it's running just fine. Sure feels good to get it back up and running again. Thanks for all the help. :{_}: