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input from mechanical fuel pump crew.
If you put 1 or 2 ounces of MMO into each cylinder, it will definitely emerge into the carburetor, and you will have to take the carb off, disassemble it and clean out the oil. The reason it goes into the carb is the cylinders are not directly below the spark plugs, but off toward the alternator side of the engine. If you just put MMO straight down from the spark plug holes, most of it will go into the valves, and down into the carb. This has happened to me, and now I use some sort of tubing or large drinking straw to direct the MMO directly to the cylinders. One of those archaic, long-spouted oil cans would work for that. I do this for winterization, and before starting up in the spring. MMO in the fuel keeps valves from sticking.
The hand bail on the mechanical pump will often have a small range of motion, depending on where the engine is in its rotation. It should still pump fuel, however, unless there is a fuel valve closed upstream of the pump. Once you know that fuel valve is open, you should be able to fill the stainless bowl just before the pump with the hand bail. If the stainless bowl is empty, the valve in the fuel line is definitely closed, unless the engine hasn't been run since the bowl was attached. When you are able to hand operate the pump until gas flows all the way to the float valve in the carburetor and pressurizes the fuel line , the pump bail will go limp with no resistance. The range of motion of the bail decreases as you pressurize the fuel system.You can hear gas flow through the filters, the pump, and into the carb as you pump the bail, until everything is full of gas. In my experience there is no vapor lock with a mechanical fuel pump. It will pump air, and inhale (here I avoid the four letter word that begins with s and ends with k) the gas through the fuel lines and filters, fill the pump bowl, and push the gas up against the float valve. This will make the needle in your fuel pressure gauge, if you have one, move off its peg and read about 3. If the gauge doesn't hold pressure you have a leak and need to look for it, or your float valve does not seal well and gas will come out the bottom of the carb into the air intake. If your pump diaphragm is broken, gas will go into the crankcase, and your fuel lines will not pressurize. This has never happened to me in 2600 hours of operation. I believe using MMO in the fuel keeps the diaphragm from drying out, and using non-ethanol gas keeps the rubber from degrading. Once there is fuel pressure, the engine should start right up with little cranking, if compression, spark, choke, and timing are in proper order.
If you put 1 or 2 ounces of MMO into each cylinder, it will definitely emerge into the carburetor, and you will have to take the carb off, disassemble it and clean out the oil. The reason it goes into the carb is the cylinders are not directly below the spark plugs, but off toward the alternator side of the engine. If you just put MMO straight down from the spark plug holes, most of it will go into the valves, and down into the carb. This has happened to me, and now I use some sort of tubing or large drinking straw to direct the MMO directly to the cylinders. One of those archaic, long-spouted oil cans would work for that. I do this for winterization, and before starting up in the spring. MMO in the fuel keeps valves from sticking.
The hand bail on the mechanical pump will often have a small range of motion, depending on where the engine is in its rotation. It should still pump fuel, however, unless there is a fuel valve closed upstream of the pump. Once you know that fuel valve is open, you should be able to fill the stainless bowl just before the pump with the hand bail. If the stainless bowl is empty, the valve in the fuel line is definitely closed, unless the engine hasn't been run since the bowl was attached. When you are able to hand operate the pump until gas flows all the way to the float valve in the carburetor and pressurizes the fuel line , the pump bail will go limp with no resistance. The range of motion of the bail decreases as you pressurize the fuel system.You can hear gas flow through the filters, the pump, and into the carb as you pump the bail, until everything is full of gas. In my experience there is no vapor lock with a mechanical fuel pump. It will pump air, and inhale (here I avoid the four letter word that begins with s and ends with k) the gas through the fuel lines and filters, fill the pump bowl, and push the gas up against the float valve. This will make the needle in your fuel pressure gauge, if you have one, move off its peg and read about 3. If the gauge doesn't hold pressure you have a leak and need to look for it, or your float valve does not seal well and gas will come out the bottom of the carb into the air intake. If your pump diaphragm is broken, gas will go into the crankcase, and your fuel lines will not pressurize. This has never happened to me in 2600 hours of operation. I believe using MMO in the fuel keeps the diaphragm from drying out, and using non-ethanol gas keeps the rubber from degrading. Once there is fuel pressure, the engine should start right up with little cranking, if compression, spark, choke, and timing are in proper order.
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