JD 45 combine fuel pump won't prime.

[Weldon K]

Trying to get my 45 started again to finish shelling some corn. It was used three weeks ago and was difficult to start then, but finally got it going with help from ether. This time it behaves as if no fuel at all to the carburetor. I tried operating the manual primer lever on the pump but it would not move. I removed the pump and got the lever to move . I placed a piece of thin poly film (such as used to wrap food in your kitchen) over the inlet port of the pump and operated the lever. It did not flex the poly film as it should have if the diaphragm in the pump was producing vacuum to the inlet port. I suspicion bad pump diaphragm. I took pump to auto parts store and a very mechanically knowledgeable man there agreed that pump was not working. I bought a new pump and installed it. I operated the manual primer lever many , many times but fuel would never come to the pump. I removed the new pump and tested it by attaching a twenty inch long hose from the pump into a bucket of hot water as I held the pump above the bucket and stroked the primer lever. It primed quickly and shot water from the outlet port. I thoroughly blew all water from the pump with compressed air and reinstalled it. Still would not prime with a hundred strokes of primer lever. There is full flow of fuel through the sediment bowl on bottom of the tank. I disconnected the fuel line at the inlet to pump and then held a balled up rag over the tank filler opening as I held compressed air hose and nozzle into the opening. It built enough pressure in the tank that fuel was forced up the fuel line and gushed out of the disconnected line at pump inlet. This proves line is clear of any obstructions. Reconnected the line to pump but still did not prime with manual lever. For some reason the pump is not creating enough vacuum to lift fuel about three feet or so from level of fuel in tank to the pump. I'm thinking that I will install a fuel line check valve in the fuel line either horizontally under the tank or in vertical area in line just after it turns upward heading to the engine. Once check valve is installed I can disconnect the line at the inlet and fill the line completely full and reconnect it to pump. With fuel right at the pump, perhaps stroking the manual lever or turning engine with starter will start sending fuel through the pump to the carburetor and engine will fire off. Anyone think this will work? Any comments or suggestions are appreciated.

 

[dairyman]

From what you describe and the tests you’ve done on the new pump and fuel line I would be looking to see if there’s damage to your fuel line between the tank and fuel pump (small crack or pinhole) allowing it to pull air instead of fuel. I had this happen on a Case 660 combine several years ago, I replaced the metal lines with rubber.

 

[olgentdc]

Trying to get my 45 started again to finish shelling some corn. It was used three weeks ago and was difficult to start then, but finally got it going with help from ether. This time it behaves as if no fuel at all to the carburetor. I tried operating the manual primer lever on the pump but it would not move. I removed the pump and got the lever to move . I placed a piece of thin poly film (such as used to wrap food in your kitchen) over the inlet port of the pump and operated the lever. It did not flex the poly film as it should have if the diaphragm in the pump was producing vacuum to the inlet port. I suspicion bad pump diaphragm. I took pump to auto parts store and a very mechanically knowledgeable man there agreed that pump was not working. I bought a new pump and installed it. I operated the manual primer lever many , many times but fuel would never come to the pump. I removed the new pump and tested it by attaching a twenty inch long hose from the pump into a bucket of hot water as I held the pump above the bucket and stroked the primer lever. It primed quickly and shot water from the outlet port. I thoroughly blew all water from the pump with compressed air and reinstalled it. Still would not prime with a hundred strokes of primer lever. There is full flow of fuel through the sediment bowl on bottom of the tank. I disconnected the fuel line at the inlet to pump and then held a balled up rag over the tank filler opening as I held compressed air hose and nozzle into the opening. It built enough pressure in the tank that fuel was forced up the fuel line and gushed out of the disconnected line at pump inlet. This proves line is clear of any obstructions. Reconnected the line to pump but still did not prime with manual lever. For some reason the pump is not creating enough vacuum to lift fuel about three feet or so from level of fuel in tank to the pump. I'm thinking that I will install a fuel line check valve in the fuel line either horizontally under the tank or in vertical area in line just after it turns upward heading to the engine. Once check valve is installed I can disconnect the line at the inlet and fill the line completely full and reconnect it to pump. With fuel right at the pump, perhaps stroking the manual lever or turning engine with starter will start sending fuel through the pump to the carburetor and engine will fire off. Anyone think this will work? Any comments or suggestions are appreciated.

 

[olgentdc]

If it were mine i would get a electric fuel pump from advance Auto

 

[olgentdc]

Maybe You can gravity feed a gas can starpped to the grain tank or something just as stable

 

[olgentdc]

If it were mine i would get a electric fuel pump from advance Auto

Case in point ,,. My 750 Massey got to loosing prime and the hand pump would not deliver much more than a spit . I piked up a electric fuel pump and put it in line right off the tank ,, Pushing fuel rather than pulling ,,. Primed up instantly, The fuel line a has a few air cracks that only leak under vacuum ,

 

[Jaden]

Try bumping the starter so the engine is in a different position, then try manually operating again. If my memory is right, if the cam has the fuel pump partially pushed, you may not get enough stroke when manually operating to pull fuel up.

 

[Jim.ME]

Trying to get my 45 started again to finish shelling some corn. It was used three weeks ago and was difficult to start then, but finally got it going with help from ether. This time it behaves as if no fuel at all to the carburetor. I tried operating the manual primer lever on the pump but it would not move. I removed the pump and got the lever to move . I placed a piece of thin poly film (such as used to wrap food in your kitchen) over the inlet port of the pump and operated the lever. It did not flex the poly film as it should have if the diaphragm in the pump was producing vacuum to the inlet port. I suspicion bad pump diaphragm. I took pump to auto parts store and a very mechanically knowledgeable man there agreed that pump was not working. I bought a new pump and installed it. I operated the manual primer lever many , many times but fuel would never come to the pump. I removed the new pump and tested it by attaching a twenty inch long hose from the pump into a bucket of hot water as I held the pump above the bucket and stroked the primer lever. It primed quickly and shot water from the outlet port. I thoroughly blew all water from the pump with compressed air and reinstalled it. Still would not prime with a hundred strokes of primer lever. There is full flow of fuel through the sediment bowl on bottom of the tank. I disconnected the fuel line at the inlet to pump and then held a balled up rag over the tank filler opening as I held compressed air hose and nozzle into the opening. It built enough pressure in the tank that fuel was forced up the fuel line and gushed out of the disconnected line at pump inlet. This proves line is clear of any obstructions. Reconnected the line to pump but still did not prime with manual lever. For some reason the pump is not creating enough vacuum to lift fuel about three feet or so from level of fuel in tank to the pump. I'm thinking that I will install a fuel line check valve in the fuel line either horizontally under the tank or in vertical area in line just after it turns upward heading to the engine. Once check valve is installed I can disconnect the line at the inlet and fill the line completely full and reconnect it to pump. With fuel right at the pump, perhaps stroking the manual lever or turning engine with starter will start sending fuel through the pump to the carburetor and engine will fire off. Anyone think this will work? Any comments or suggestions are appreciated.

When you stroke the manual priming lever on the pump do you feel resistance through most of the stroke? You should be feeling some resistance, if you don't, I agree with Jaden. Bump the engine a bit with the starter. If the cam has the lever that runs on the cam stroked, the priming lever doesn't work effectively. Check the supply hose from the tank to the pump, it may be getting porous, as has been suggested. How much fuel is in the tank?