IH Carb
Posted: Wed Dec 26, 2012 1:34 pm
The cub I just purchased needed a carb rebuild (according to the previous owner) as it wouldn't idle. He hadn't tackled that sub-project before his heart attack slowed him down.
No problem, sez I, I'll read up on the IH carb and git-r-done. So I read every thing I could find on the subject - most of it located on this site and very comprehensive. When I pulled it apart, the first thing I noticed was the broken & missing idle tube. Aha! Very Common. But what puzzled me was the lack of a main jet... I mean it wasn't there... no hole in the bowl for one, either. Temporarily skipping that, I stripped everything down and after an overnight solvent bath and two hours in the heated ultrasonic tank I noticed a faint impression of where the main jet SHOULD have passed through the outer wall of the bowl. As it turns out, someone, years ago, had broken off the main jet at the end of the threads. Noticing that fuel would leak from the outside hole in the bowl, they plugged it by hammering in what appears to be lead fishing sinkers and dressing the outside flush! However, it did work and it didn't leak, so I guess I can't argue with the utility of the repair. LOL! After drilling out the main jet and re-tapping I resurfaced the area where the main jet gasket contacts the outside of the bowl.
Also noticed the upper housing was warped from overtightening. Having seen references to several plates online here I made my own. It works very well.
Flipped the plate upside down and used it as a jig to hold the upper housing square while I drilled out the broken idle tube.
Now we wait until my rebuild kit arrives from Steiner...
No problem, sez I, I'll read up on the IH carb and git-r-done. So I read every thing I could find on the subject - most of it located on this site and very comprehensive. When I pulled it apart, the first thing I noticed was the broken & missing idle tube. Aha! Very Common. But what puzzled me was the lack of a main jet... I mean it wasn't there... no hole in the bowl for one, either. Temporarily skipping that, I stripped everything down and after an overnight solvent bath and two hours in the heated ultrasonic tank I noticed a faint impression of where the main jet SHOULD have passed through the outer wall of the bowl. As it turns out, someone, years ago, had broken off the main jet at the end of the threads. Noticing that fuel would leak from the outside hole in the bowl, they plugged it by hammering in what appears to be lead fishing sinkers and dressing the outside flush! However, it did work and it didn't leak, so I guess I can't argue with the utility of the repair. LOL! After drilling out the main jet and re-tapping I resurfaced the area where the main jet gasket contacts the outside of the bowl.
Also noticed the upper housing was warped from overtightening. Having seen references to several plates online here I made my own. It works very well.
Flipped the plate upside down and used it as a jig to hold the upper housing square while I drilled out the broken idle tube.
Now we wait until my rebuild kit arrives from Steiner...