Calling all fuel pump guru's

[squonk 39,019]

My new to me c-160 with the K-341 was running great but the fuel pump leaked gas. I didn't want to mess with it but seeing the muffler is right next door I thought I had better fix it. I took it off and gave it to a local small engine repairman. he put a new diaphragm in it and it will pump like crazy when you push the pump lever with your hand. Once installed it won't pump at all. I know I have plenty of fuel. I can leave the pump outlet hose off, open the tank valve and fuel will run out of the outlet of the pump. I crank it over and nothing. I have had this pump on and off about 30 times. I can look inside the engine and see the cam turn and can see the lobe. I can stick my finger in the hole and feel the high spot on the cam. I put that pump on so the lever is on the top of the cam but I don't feel the cam pushing on the lever as I turn it over by hand. Is there any way by taking the pump apart the angle the lever could change so it's not hitting the cam?

[Rollerman 290]

It might be your cam follower on the pump isn't rideing on the cam lobe properly?

Take the pump back off, shine a light in the hole the fuel pump sets over & make sure you can see the lobe & how the follower is suposed to ride on it.

Also when the new diaphram was installed did you or the repairman make sure the fuel pump surfaces were flat?

The corners (thos 4 screws) tend to get over-tightened distorting the body of the fuel pump.

If it gets bad enough the pump will suck air or spit fuel out the seam, but not get gas to the carb.

[rmaynard 14,932]

When the diaphragm was replaced, could one of the check valves have fallen out?

Bob

[squonk 39,019]

I can see the lobe on the cam. I see the wear spot on the pump lever. I am assuming the lever should go between the pump mounting edge of the block and the cam so when the cam comes around the lobe will push it. As I stated this pump will push fuel like mad when you move the lever with your hand. It doesn't seem to be contacting the cam lobe and I don't see any other way I can install the pump. :ychain:

[rmaynard 14,932]

Here's the old school method of testing.

Take out the four screws that hold the top section on. Remove the top section. Check to see that the check valves are both in place. If you don't mind the taste of gas, blown on the inlet side. Air should pass. If you suck, you should get nothing. Then move to the outlet side. Suck, and you should get air, blow and it should not allow air to move. If that is all correct, remount the pump to the engine with the top off. Turn the engine over by hand and watch the action of the lever. If it is installed correctly, you will see the movement of the diaphragm actuator.

Bob

[TT-(Moderator) 1,128]

If the "rod" on the diaphragm is connected correctly to the arm and the pump is installed right side up, (fittings on top) it should pump - especially since it worked before it was removed. :ychain:

[Indy w h 4]

Could it be that when the pump was rebuilt they put the top on wrong??

Like the in is out and the out is in?? Just a thought

Make sure the gas is going in the "in" side of the pump

Indy

[squonk 39,019]

Here is a pic of the pump mounted. There is an arrow on the pump body and the fuel is going in at the correct end. Like I said, off of the engine with the fuel lnlet line connected it will pump by moving the lever with your hand. As a matter of fact , it will pump fuel about fuel about 5 feet up. (ask me how I know ) I really think for some reason, the cam is not pushing the pump lever. I'm going to try all the suggestions made by every one. I even bidding on another pump on E-bay Mike

[Helmer 0]

I think the pump is upside down.

[TT-(Moderator) 1,128]

I think the pump is upside down.

No - that's correct. It's just a "severe service" Carter pump ~ which looks a bit different than the standard pumps.

[squonk 39,019]

I think the pump is upside down.

No - that's correct. It's just a "severe service" Carter pump ~ which looks a bit different than the standard pumps.

I took the pump off again and measured the distance from the pump mounting surface of the block to the cam lobe. It's about 2.4" I measured the distance from the pump face to the end of the arm. It's about 2.8" As far as I can tell, there IS NO WAY that cam is not pushing the pump lever. I think there is something going on inside that pump. I'm going to get another pump anyway and see if that will work then I'll tear this one down. For the mean time, I got the pump bypassed and the tractor will run as long as I keep the tank past 1/2. Here is a pic of the pump off. The lever is a little different than the one TT had.