QuestionQUESTION: '75 Midget won't start. I removed fuel line from carb. and noted no fuel going to carb. Replaced fuel pump and still not getting fuel to carb. If I remove the fuel pump I can manually move the lever and gas is delivered to the carb but after installing it....again no fuel. I suspect the old fuel pump worked as I can manually move the lever and I "feel" suction. What other reasons would fuel not move through the system? Why do I get fuel if I remove the pump and manually move the lever.
ANSWER: Hi David,
Two things you need to look at. One is you have to be careful when installing the pump to slide the pump straight in as it is possible to get the pump arm off the cam lobe and sometimes even though the cam rotates the arm will not climb up on the lobe. The other is the length of the arm has to be correct for the application, meaning some pumps were meant to have an insulating block and thus they had longer arms. Some were meant to run without a spacer block and thus a short arm. The short armed pump will not operate the pump if a spacer block is used and if the long armed pump is installed on without a block, it can damage the pump so it will not work also.
The way to tell if either is the problem, remove the pump and put something in the hole to measure from the mounting flange to the cam and rotate the engine and measure several times to get a picture of what the cam movement is and then measure the pump from the mounting flange to the arm part that hits the cam and you will see if it is the correct pump for use with or without a spacer block. Yes they can be switched if the spacer block is used with the long arm pump and no spacer block is used with the short arm pump.
Howard
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QUESTION: Thanks Howard for the fast response. Couple things more if you don't mind. The arm of the new pump "looks" to be the same length as the old. The old pump did not use the spacer. Do you think I should try using the spacer (I can order one for a dollar)? The other more worrisome point is the reason I'm replacing the pump is the old pump was not pumping gas. I'm wondering what could be wrong when both old and new pumps are not getting gas? As I say I can hand pump and get gas...even with the old pump.
ANSWER: David, if you have a reason you don't want to do what I told you to do, that's OK. Take it to a shop to get it fixed.
Howard
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QUESTION: Wow-a bit testy Howard....No I don't want to take it to a shop. The mechanics on these cars are pretty straight forward. One of my questions was do you know of anything else it cold be as I believe the old fuel pump, which pumps gas if you manually operate the lever, stopped pumping gas while attached to the engine. A better answer to my question about the spacer would be to do your measurements as suggested but if all else fails try the spacer in case you have a long arm pump. For only a dollar it's a cheap experiment. By the way your instructions "you have to be careful when installing the pump to slide the pump straight in" is a bit misleading. Because of the small size of the hole in the engine block you must tip the pump to get the arm through that hole while attempting to align the pump to the pump bolts on the engine. Once you get the pump arm in it should easily (relatively) slide into the engine bolts straight on. If not a good suggestion is to crank the engine for a second to spin the cam....doing that a few times should allow for the pump arm to slide in without hitting the raised or high lobe on the cam.
AnswerDavid, think of this as you are in the Army and I am your drill instructor.
When installing any cam driven pump the arm can slip off of the lobe to the front or back and if the pump is bolted up that way the arm may not climb onto the cam lobe. If you will do what I say you will find the problem. Since you don't want to measure to see if it is correct do this, Turn the engine over until the high point of the cam is facing the arm and hand place the pump in place and feel if the pump arm needs to be compressed to get the pump flange up to the block. Note how much clearance there is between the pump and block when the pump arm feels like it has started to hit it's spring. If you have very little to no spring feel of the arm against the cam then this pump will never work, if you feel that the pump spring is almost fully depressed you probably need a spacer block or the pump diaphragm will be damaged when you bolt it up.
If the pump works by hand then it should be obvious that the cam is not operating the arm either because it is not contacting the arm, the arm has slipped off the front or back of the lobe or the pump should have had a spacer block and the over compression of the arm has bent or damaged something in the pump. End of story! Stop wining about how I tell you how to fix this car or I will fire you and not allow you to work on this car. lets keep our roles straight, me chief you Indian.
Howard
