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Mkiester 
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Joined: 11 Aug 2025
Location: Minnesota
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 Topic: 1947 WC Allis Chalmers Will Not Start
Posted: 11 Aug 2025 at 6:51pm |
Hello. We have a 1947 WC Allis Chalmers that will not start. We have installed a new condenser, new spark plugs, fresh gas, and rebuilt the carburetor. The engine turns over but will not fire. The timing has been checked, and there is spark being generated by the spark plugs. We are thinking that there might be a stuck valve.
The tractor has been stored inside an insulated garage, but has not been run in about the last 3 year.
Any help that can be provided to us would be greatly appreciated.
Sincerely, Chuck and Mike |
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steve(ill)
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Location: illinois
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Posted: 11 Aug 2025 at 7:54pm |
You see the SPARK turing by hand or the starter ? Turn by HAND and make sure you get the FIRE at the TDC Top Dead Center Mark.. The MAG will advance to FIRE after startup.
Look at the plugs.. If they are dry, you might try putting a spoon full of gas into each hole and then installing the plugs.. If you have good SPARK, have you tried starting fluid sprayed at the air cleaner ? If you get a POP - POP then you know you have spark... If it actually will RUN on the fluid, then you know the timing is close to correct.
Rebuilt carb does not guarantee you have gas flow into the bowl and getting into the intake.
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Mkiester
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Posted: Yesterday at 10:15am |
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Thank you for responding! Can you provide more clarification on what you mean by “ Rebuilt carb does not guarantee you have gas flow into the bowl and getting into the intake.”?
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steve(ill)
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Posted: Yesterday at 10:21am |
gas needs to flow thru the steel tube out of the gas tank to the carb.. Float needle needs to work properly to let gas flow INTO the bowl.. If you took the drain out of the bowl and you can see fuel draining at a GOOD RATE, then you might be OK... Have seen many "rebuilt" carburetors that dont have good flow thru the tube, dragging float on the bowl restricting inlet, passage way in carb STILL PLUGGED with gunk even after a "rebuild"..
A lot depends on if the carb was disassembled and washed in a can of gasoline, or if each passage way was RODDED out and blow out with air and guarantee open..
look at your SPARK PLUGS.. If you choke the engine and it does not FIRE, crank and the plugs are DRY, you have a FUEL problem.
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steve(ill)
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Posted: Yesterday at 10:26am |
what im saying is if you CHOKE the engine and crank for 10 seconds, then look at the plugs.. If they are DRY, you have a fuel problem... If they are WET, you have a spark/timing problem.
If the plugs are soaking wet, they may be fouled out.. You would need to warm the end up with a propane torch to boil off all residue, then start over.
Edited by steve(ill) - Yesterday at 10:27am
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Mkiester
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Posted: Yesterday at 11:09am |
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We are able to open the bowl drain valve and fuel does run out at a good rate. Also the carb was rebuilt by a qualified shop and was ultrasonic washed and had new parts installed inside. There is definitely gas not getting to the combustion chamber.
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bill2260
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Posted: Yesterday at 11:12am |
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Check your manifold gaskets.
Engine cylinder compression makes the fuel travel up to intake. If they leak, fuel wont make the trip
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Mkiester
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Posted: Yesterday at 11:55am |
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Thanks. Is there anything else that could cause low cylinder compression?
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steve(ill)
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Posted: Yesterday at 2:20pm |
it is possible that the pistons rings are STUCK to the piston and not sealing well against the liners.. That might make the compression drop to 40- 50 psi and motor will not start... If you can check compresson, do that... if not, you could dump a couple ounces of oil into each cylinder, then reinstall the plugs and see if it will start.. The small amount of oil can help plug the ring clearance and buildup pressure until engine starts.. Once running, keep engine above 1000 rpm for a few minutes, to see if rings will come loose and seal..
another possibility is that a couple valves got STUCK in the head ( due to setting and slight humidity / corrosion setting in ) and bent a couple pushrods when you first cranked it over... and you have low compression because of that.. You would have to remove the hood and valve cover for inspection..... checking compression FIRSt is good idea, if you have a gauge.
Edited by steve(ill) - Yesterday at 2:22pm
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steve(ill)
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Posted: Yesterday at 2:23pm |
We are able to open the bowl drain valve and fuel does run out at a good rate. Also the carb was rebuilt by a qualified shop and was ultrasonic washed and had new parts installed inside.
Excellent... you have eliminated that possible problem !
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Les Kerf
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Posted: Yesterday at 4:15pm |
 steve(ill) wrote:
it is possible that the pistons rings are STUCK to the piston and not sealing well against the liners.. That might make the compression drop to 40- 50 psi and motor will not start...
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Yup. Or even lower. I am currently messing around with an old derelict Model C on which I installed a B-125 combine engine that was stuck. We pulled the head and did a minimal valve job but never removed the pistons. Hand cranking to attempt starting resulted in an occasional pop with ether but no joy.
Hand cranking to do a compression test showed about 45 PSI on #1 and #4 with #2 and #3 at about 10 PSI after adding some oil to the cylinders.
We connected the tractor to my other Model C via the flat belt pulleys, gave it a whirl and she fired right up! (There were other issues about which I shall post in a new topic).
It is important to understand that ring sealing not only contributes to compression, but it is also necessary in order to develop enough vacuum signal to pull the fuel into the cylinders. The spark plugs in this engine were bone dry during the hand-cranking session, and I absolutely know that the carburetor is good.
Spinning the engine at ~1000 rpm with the belt pulley will definitely improve the odds 
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