Fuel pump for a 41

notdavidspade · October 14, 2009, 10:39:30 PM

Well, drove it around the block both days this passed weekend. I'll drive it more often when it has a seat and a windshield. The added air flow was nice, but the toolbox didn't make a very good seat.

JimCno · October 12, 2009, 11:05:24 AM

Sounds like you have things figured out. Isn't that a great feeling!? Now drive it as often as you can.

notdavidspade · October 11, 2009, 11:26:59 PM

Alright... got my running and fuel issues sorted out.
Problem one: Fuel supply. Determined that there was no blockage. Ran compressed air to the tank filler and a steady stream would go to the fuel pump. Still, fuel pump was not providing enough fuel. Dropped the tank and figured out that the coupler attaching the fuel line to the tank didn't go far enough into the tank to seal against the pickup tube inside. This caused the fuel to become aerated as it was drawn from the tank causing poor fuel pump performance. Solved by grounding down the brass to allow the fitting to travel further into the tank and used a fuel resistant o-ring to form a good seal.

This allowed the engine to start and stay running. Idle was still poor, would stagger and miss. Would not rev and occasional back fire from carb.

Problem two: Ignition. Filed points... replaced wires in distributor, adjusted timing. Adjusting the timing cured the main idle problem. With a decent idle, the carb settings could be adjusted and now it purrs like a Plymouth. Immediately drove two laps around the neighborhood and came back for a celebratory beer. These cars are much more interesting when you can drive them.

notdavidspade · August 27, 2009, 12:45:16 AM

Haven't been out stinking up the garage recently. Did get the brakes bled though. I'm not suspecting the fuel tank at this time, although you not the first to point that out, so its probably worth investigating. I need to get a brave soul to look down the carb while its running and see if it looks like gas is dumping down or not, but I'm suspecting my carb right now. Thanks all for your continued responses. I'll keep everyone updated.

Doran Johnson · August 20, 2009, 04:02:59 PM

Have you found the problem yet? If not, try disconnecting the fuel line from the tank, at the pump. Attach a temporary line to the fuel pump from a fuel can. If it pumps and runs from the can, then you have a blockage from the tank.

TodFitch · August 17, 2009, 07:16:01 PM

Quote from: g6001 on August 15, 2009, 11:05:05 AM
I just read the sting on the fuel pump.? My recent experience was two weeks ago on Sunday, driving the PT-81 and it just stopped dead in the middle of the street - just quite running. Took a roll-off ride home (thanks AAA) and discovered that the shear pin holding the pump arm of the fuel pump had dislodged and the arm was not ridding on the crank nor pumping. The pin was 3/4 hanging out the side. Took the pump off. Made a new pin and pinned it on.? Runs great.? Strange circumstance - never experienced anything like that before.

Jack Gallagher
Bethesda, Maryland

Over on the discussion forum at http://www.p15-d24.com/ there have been a number of people who have had the pin come out of new pumps. Seems like there is an issue with at least one of the manufacturers of this model pump nowadays. It is probably a good idea to stake the pin before installing the pump.

g6001 · August 15, 2009, 11:05:05 AM

I just read the sting on the fuel pump. My recent experience was two weeks ago on Sunday, driving the PT-81 and it just stopped dead in the middle of the street - just quite running. Took a roll-off ride home (thanks AAA) and discovered that the shear pin holding the pump arm of the fuel pump had dislodged and the arm was not ridding on the crank nor pumping. The pin was 3/4 hanging out the side. Took the pump off. Made a new pin and pinned it on. Runs great. Strange circumstance - never experienced anything like that before.

Jack Gallagher
Bethesda, Maryland

Jim Benjaminson · August 12, 2009, 10:50:53 PM

Had a similiar problem with a "sealed" gas tank. It had been sealed years before non-leaded gas was abolished. After I started using the "new" gas, I had problems - it would lift the sealer and grag it to the fuel pump, plugging it up. Had to tank off and clean the tank, only this time I didn't use any sealer and haven't had a problem since.

MRR41 COUPE · August 12, 2009, 09:13:38 AM

I had a similar problem with mine. I kept removing it and It worked great between pails. What happened is when I got the gas tank reconditioned the gas line outlet was plugged solid in the tank. The new sealer in the tank plugged it up solid.

notdavidspade · August 11, 2009, 10:32:43 PM

Hi guys, thanks for the replys,
The steel lines are brand new, I bent and double flared them myself. The rubber line is a few years old but seems to be in good condition. I'll replace it in the next day or so just to eliminate it as a potential problem.

John, the fuel tank should be fairly easy to drain by either disconnecting the line from the tank or if yours is like mine, the fuel line has a coupler on the drivers side frame about a foot from the rear of the front tire. Disconnecting at either point should make short work of dumping the fuel.

John Hendricks · August 11, 2009, 11:00:00 AM

I am currently working on a similar sequence of events like u describe in my 49 Dodge truck. I have determined, by blowing air thru the fuel line from the tank that I have an obstruction in the steel line from the tank, or in the tank itself. And the tank has about 8 or 10 gallons in it as i recall- the gauge isn't working. I am cogitating on a safe way to get the tank empty and out of the vehicle.

Jim Yergin · August 11, 2009, 09:47:52 AM

Stephen,
What is the condition of the fuel lines from the tank? Is it possible you have a small leak in the line so that you lose prime or the flex line from the frame to the pump is old and collapsing internally thus blocking the line?
Just some random thoughts.
Jim Yergin

notdavidspade · August 11, 2009, 08:19:53 AM

Fuel pump is about a week old to me. Bought from Rock Auto and it came in a new style box (generic Carter box with a picture of an electric fuel pump and the part number sticker on the top) so I don't think its very old. Regardless, this condition occured with the old pump and this new pump, so I don't think it is the pump itself that is bad.

TodFitch · August 11, 2009, 05:13:15 AM

How old is the fuel pump? Is it old enough that it has valve and diaphragm components in it that are being attacked by the additives in modern gas. Making he check valves stick for example? (This includes a NOS pump that has been around forever on the shelf before you used it.)

You might want to rebuild it with parts that stand up to modern gas. Antique Auto Parts Cellar (a.k.a. then & now automotive) carries rebuild kits and they aren't that hard to rebuild.

notdavidspade · August 11, 2009, 12:36:11 AM

Hi Pat,
Thanks for the part numbers.? I'm not suspecting the cam lobe, The engine is a fresh rebuild with probably an hour of run time on it and less than a mile driven.? The engine use to run and would idle great two years ago before I started the major restoration on it.? The fuel pump is a carter M847.? Not sure how well that crosses over to the plymouth numbers.?

36 Ply · August 10, 2009, 09:01:45 PM

Steve-

According to the March 20, 1941 edition of the Plymouth Parts List (1941 Models), there are several pumps listed; right hand drive, left hand drive, booster, non booster and 12 volt right hand drive (military?).
I will list the left hand drive pump numbers; if you need others, let me know.

Non booster - 695808 Booster - 695805 these are for P-11 and P-12

Auto Pulse - 673052 this is for P-11 and P-12

Regards,
Pat O'Connor

36 Ply · August 10, 2009, 08:41:56 PM

Steve-

I'm wondering if the fuel pump lobe on your camshaft may be worn. Only thing that occurs to me at the moment. After supper, I'll research the correct pump for a '41.

Regards,
Pat O'Connor

notdavidspade · August 10, 2009, 11:43:38 AM

I have a fuel problem that is driving me nuts. I disconnect the line to the carb, place a coffee can by the fuel outlet and crank the engine, and get nothing. I can unbolt the fuel pump and pump it by hand and it will squirt fuel. Then bolt it back on and crank the engine and it works again... until today when it isn't pumping again. I've replaced the fuel pump with new and still have the same issue. Can someone verify what model fuel pump should be used? Any other ideas? Thanks!
Steve in FL.