300 IH Utility Shuts off when throttling up RPMs

Anonymous-0

Well-known Member
I have a 1955 300 IH Utility That will start and idle fine, but when I start to rev up the RPMs (give it gas, or pour the fire to it)it sputters and shuts off. The tractor was converted from 6v to 12v ignition many years ago and had ran fine for a long time, then started to have trouble with throttling up the rpms. I have replaced the distributor with an electronic ignition set, and checked the amperes across the unit with a volt meter and some math. Everything seems to be within amper specs of what is recommended for a 6v to 12v conversion(i.e.I tested the voltage through the coil and distributor and coil and got 11.95 volts then found the ohms across the coil. + to - side was 3.97 ohms and then divided the volts by the ohms to get around 4 amps. Which is what was recommended for a 4 cylinder tractor. Then replaced sediment bowl and strainer, checked and cleaned fuel tank, fuel line and filter, and cleaned carburetor(but not sure if carburetor needs rebuilt or not). Fuel was flowing to and through carburetor.I set all adjustments to specs, but tractor still wants to shut off when throttled up. Any Ideas please?
 
Make sure your filter is for gravity fed use. Also disconnect the gas line from the carb and see if there's a full stream of gas from the tank.
Use a clean container to catch the gas. If that looks ok remove the tube fitting where your gas gas line connects and look for a screen. If that carburetor has a main jet adjusting screw similar to what's used on the H and M letter tractors. Open that as that will enrich your fuel mixture.

Pull off one of the plug wire's and have a helper to throttle up the engine and see what your fire from the plug wire looks like. If it isn't blue your electronic ignition may be the problem. Hal
 
You may have two issues.
1) The fuel mixture may need to be richer to allow the engine to pick up speed. Is it worse in cold weather??? You need a richer fuel mixture in cold weather. So if it is worse when cold you just need to richen the fuel mixture up. Try pulling the choke out just a little when you try to throttle it up. IF that helps your problem is in the carburetor.

2) Your coil maybe breaking down under load. It is a common problem. Checking a coil with an ohm meter is useless. It would only show one that has an open. The resistance check is not very reliable check of how it will spark under load.


I have also found this problem to be much worse with the new formulated fuels. The original all gas worked better.
 

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