My father has a 1963 Allis Chalmers D-17 tractor. It’s been in use almost daily on my dad’s farm since the ‘70’s. Since my dad retired 8 years ago from farming, it no longer gets used daily, however he uses it once a month or so. He used it in November for cutting brush and parked it in its spot in the shed as he always does. He went to use it again in December and it would not start.
We tried to pull start it using another tractor (which we’ve done a million times over the years with everything), but it just wouldn’t run. I’m wondering if any of you engine guys would have any idea what is causing this non start problem on this simple motor.
It’s a 50 hp, 4 cylinder, carbureted, 2 valve pushrod motor. When trying to start it via the starter or pulling it, it’ll smoke gray smoke, but won’t fire. The plugs get wet from fuel. Timing is correct and has been checked. The plugs spark nicely and at the correct time when you test them by grounding them on the outside of the block. The points are clean and the cap, rotor, wires and condenser are relatively new. Compression testing with a basic compression gauge reveals ~120 psi per cylinder on all 4 cylinders. The carb looks clean and in good adjustment. The fuel has been drained and replaced with fresh fuel. The air cleaner is cleaned (oil bath type cleaner) and the air intake tubing is free from obstructions. The plugs are brand new Champion J8’s. The tractor was parked after he used it in November and the thing ran fine at that point.
The tappet cover has been pulled to check the valves & pushrods to see what’s going on with the valve train and all looks good.
However, the biggest mystery is that if you put your hand over the carb intake area, you’ll get blow back backwards through the carb as you crank the motor. It essentially shoves air (and fuel?) backwards through the carb. The throttle and linkage seems to be O.K., but that is one thing that needs to be checked yet.
Any and all thoughts and ideas are welcomed as to what might be causing this condition.
Thank You!
Jay
90 964