fuel pump issue

[labguy]

A have an L20B that I've dropped in my 73 620 but I can't seem to get the fuel pump to work. The motor had what appears to be a new fuel pump on it but after trying to fire the engine I discovered that the arm on the inside wasn't even close to eccentric on the end of the cam (wrong pump I guess, probably why the donor truck was $100). So I took the pump off of the running 1600 that I took out of my truck, it looks like it's making proper contact with the cam eccentric but it still won't pull any fuel through. So I have two questions:

 

1. Are there different types of eccentrics for the cam?

2. What should I run for fuel pressure (it has a stock carb, cam etc) if I put an electric pump on it?

 

Thanks in advance for the help.

[datzenmike]

Compare the L16 eccentric to the L20B one.... they should look the same. Carefully fill the carb on the L20B by dribbling gas into the vent tube until it shows on the sight glass on the front. Fire it up. It's hard to prime the fuel lines and pump by just cranking it. With a full carb it should run for half a minute or so and that should be enough to suck up fuel.

 

 

If it won't fire pull the coil wire and hold near ground to confirm you have spark.

[labguy]

Thanks, I'll try that. I,ve been dumpimg a little fuel in the carb to fire it but your right it doesn't fill the lines or carb bowl. I would look at the 1600 eccentric but I gave that motor to another Ratsun guy to put in his 510.

[datsunaholic]

L16, L18, L20B cam eccentrics are identical. Dunno what pump you have, POSSIBLY someone stuck the pump on with no spacer, which bent the arm, then installed the spacer and now it doesn't reach?

 

Oh, and make sure the lines aren't plugged. Lost of times the lines get rust in them and plug up, you'll never get fuel that way.

[villegs]

I have this same problem, the arm for the pump is too loose, it can wiggle left and right, enough so that it won't stay in place on the eccentric and actually was grinding the front of the cam gear, thought I just needed a valve adjustment, good thing I got the cam cover off before any bad damage occurred. I'm switching to an electric pump.

[Pacific coast Datsun]

I have this same problem, the arm for the pump is too loose, it can wiggle left and right, enough so that it won't stay in place on the eccentric and actually was grinding the front of the cam gear, thought I just needed a valve adjustment, good thing I got the cam cover off before any bad damage occurred. I'm switching to an electric pump.

I had this same issue when i installed a cheapo fuel pump.......

the arm had some play,,to fix it i cut 2 small washers so they looked like letter C's. Wedged then JB welded them on either side of the arm between the plastic pieces...this pic doesnt show the fix though...

ran fine after that.

[labguy]

thanks for all the good suggestions...The pump looks right on the eccentric so I think everything is ok in that area however it does have some side to side movement. Does anyone have a suggestion for the correct fuel pressure, I'm thinking that if I have to buy a new pump I'm going to go with an electric and a fuel regulator. I'm guessing 3-5 lbs running should be good.

[datzenmike]

Stock pressure is 3-3.5 any more and it could flood.