|JCrutt said: (quoted from post at 20:41:31 12/02/12) Doug, I considered that but the good power has lead me to put that idea on back burner for now.|
Thanks for the imput. Basic mechanical tests and inspections show good. As diesel mechanic is why it has me stumped and I realy don't understand how the vent pump is supposed to work. I want to cover everything else before I do a tear down. I've never seen a 2cyl do this.
You ought to get a current hot compression check as well, in case the cylinder that is in not too good shape is really worse than you think.
The vent pump sits at the base of the fanshaft, governor end, and depending on the model year, is either a rotary vane or roller pump, so it pushes air into the crankcase anytime the engine is turning and the fan is spinning. Depending on the model year...and I'm guessing on your S/N, clean air is drawn from the air cleaner down the fanshaft tube, pumped into the governor, to the crankcase, and it crawls forward to the valve cover, where it is exhausted via pipe to the carb intake elbow to re-burn any nasty fumes. Later models had a separate inlet pipe.
Had an "A" one time the pump vane seized, as many do, and it would suck gobs of oil into the carb. Quick fix was to drill a small hole in the side of the fill pipe nipple until you could get around to pulling the fanshaft. This post was edited by F-I-T at 19:58:02 12/02/12 2 times.