1937 248 Fuel Pump Issue?

Probably should have started this thread here first.

My 1937 Buick has been in a shop getting a "driver restoration". I had the tank cleaned prior to it going to the shop. I replaced with a new float and checked the sending unit for proper resistance. They made new fuel line. 3 weeks ago they were having trouble keeping it running. If they filled the carb it would run then starve. I asked then if I could send my spare fuel pumps. I believed that I rebuilt and remounted the pump that came with the car when I drove it home 25 years ago. Now not shure but I checked the 2 I had here at home. The one I rebuilt is an AC and seems to have had better suction. Checking the ones I have here The ACs actuating lever projects out 1 7/16" unloaded, 1 1/4' when spring is compressed (before pressure/tension on diaphram). The other pump which now I believe was the one originally on the car(not rebuilt) is CM brand, has the lever projecting 1 5/16" unloaded and 1 3/16 spring loaded. This past week they said it has the same issue only now after manualy filling the carb bowl it will run at idle. But will run down the battery and still won't get fuel to the carb. They put on another pump from a 1937 248 engine they have in the shop. Same result. Now they are saying that the cam lobe may be worn. Don't see how since the car ran great home and ran well for several years till I removed all accesories when I began to clean up the engine. Should I ask them to check their work? Ie. kinked line, poor seal at sending unit. The car is now 2 hours away and will finally have to send my extra pumps to be checked. I can't check my 20 year library of the "Torque Tube" since they have it at their shop.

Larry<!-- google_ad_section_end -->

Hi, Before you tear your hair out, disconnect the suction side of the pump and have someone turn the engine over, put your thumb over the fitting on the suction side of the pump and see if there is in fact suction. You could also fasten a flexible line to the pump, putting the other end into a container of fuel and see if it sucks that up. If the above steps don't work out satisfactorily, I would suggest using an electric pump it will save a potential engine tear down to replace the cam.

If it sucks it out of the gas can-----take off the gas cap and use compressed air to blow back through the fuel line to the fuel tank. It should bubble and make an awful fuss. If it doesn't, you have a partial block in the fuel line, fuel filter or fuel pick up line in the tank. (they get kinked very easily) Good luck! Look on the bright side, It RUNS! I bet you it is an easy fix. Also, the diaphram in the fuel pump may have deteriorated from the ethanol in today's gas that wasn't there 25 years ago.

Dwight

I'm not sure the 37 has the same fuel tank sending unit/fuel pickup as the 39, but the fuel pickup tube that passes through the top of the sender can break loose but still look like it's in place. This caught us out a while back. You should be able to reach up to feel the tube on top of the tank while under the car. Try to move it. If it moves, there's an issue and a new sender is required!

Cheers

Grant

Hi Larry,

The use of a vacuum gauge will take a lot of guess work out of this one! Remove both the inlet and the outlet lines from the pump, remove the spark plugs and wind the engine over about eight revolutions on the starter whilst holding your finger over the pump outlet, after you have stopped turning over the engine remove your finger from the pump outlet and if the pump is OK you should hear air escape from the outlet, if not then the pump needs attention. Should you have a pressure gauge to connect to the outlet a reading of 2.5 to 3.5 psi. would be expected. If it passes the first test connect a vacuum gauge to the pump inlet and repeat the engine eight turn spinover on the starter and when you stop the pump should hold a vacuum reading of about 10in of vacuum which should only drop slowley, if you don't get a vacuum reading or it drops off as soon as the engine stops spinning this indicates a faulty pump. If you get a good result with the vacuum gauge reconnect the fuel line to the pump inlet and disconnect the fuel line at the tank gauge fitting and connect the vacuum gauge to the fuel line and repeat the engine spin over test. A good gauge reading tells you the line from here to the pump is OK but a bad reading indicates an air leak in the line between there and the pump.

If the above tests give good results you need to check the pick up tube in the tank for restriction or air leakage or if that's all OK reconnect the lines to the tank pick up and fuel pump and disconnect the fuel line at the carburettor and direct it into a suitable container whilst doing the spin over test and see if it discharges fuel, if it does you then can be sure the pump and lines are not at fault and the problem is narrowed down to the carby such as a blockage at the inlet or a stuck needle valve.

You might be lucky enough to have or to obtain a proper fuel pump test gauge which has the pressure and vacuum functions contained in the one instrument. All the above might seem a bit daunting but really it is simple and foolproof and accurate.

Good luck.

Mike Hanning

Christchurch

New Zealand

BCA #40630

We are the ones doing the work on this car and we appreciate the advice but this isn't our first rodeo. There is all new line from pump to tank. There is no leakage or restriction from tank to pump. If we disconnect the fuel line at the pump and rig up a pickup from a gas can on the runningboard the pump has great difficulty pulling gas up to the carb before the battery dies. If operated by hand the pump has good suction and holds that suction. On the car it shows very, very little suction. We tried another rebuilt pump from another 40 Series we just happened to have here with the same results. Conclusion...the cam is not providing enough lift to properly operate the pump. Alternate theories will be entertained. We did not disassemble this car. The owner did say that it seemed to run out of fuel on long hills before he began restoration 25 years ago. I suspect an electric fuel pump may be in this car's future though we don't like to use them unless absolutely necessary.

Thanks all who joined in to help with this problem. I have sent my extra pumps. The AC pump may have an 1/8" more movement as noted in my first post.

I oppologize to any one who has to work on a car that was partially dissasembled over 20 years ago. I tried to keep track of what I did. Consulted the 37-38 Buick Club's "Torque Tube". Bought parts from vendors that "promised" they were for my 1937-41 special. Restorer 32 has already had to sort through some of the incorrect parts I had assumed were correct.

Just hoping this would help.

Larry

Hey, we are happy to listen to anyone's advice, you can always learn something new. At least 50% of the vehicles we work on arrive here disassembled either by the owner or by another shop that for some reason couldn't finish the job. If there is one thing I've learned it's that working on old cars is a frustrating and time consuming endeavor. I personally own a car that was disassembled in 1969. We recently completed an MG TD that was taken apart by the owner 39 years ago. In about 1980 I bought a 1921 Overland that had been disassembled by the owner in anticipation of a total rebuild in 1935!

Sent the spare pumps to Restorer's shop. Should have gotten there on thursday. We will see what the verdict is.

Larry

This is an update on my 1937 still at the shop, about the fuel pump and carb situation. The rebuilt AC pump I sent down to them is doing its job. Hooray! But they indicate that there are problems with my "rebuilt" Marvel carb. This is their description....("There are problems with the carb. The throttle shaft is badly worn and should be rebushed. There is an issue with the linkage. Depressing the accelerator pedal does not move the lever operating the accelerator pump in the carb sufficiently to squirt gas into the throat, making it difficult to start the car. If operated by hand the pump works as intended. Wrong linkage maybe? Possibly internal adjustment? We are reluctant to open up the carb. The car is tuned as finely as we can given the worn condition of the throttle shaft. The longer stroke fuel pump you sent does make a difference. In any case it runs well once started and drives and stops".)

My response:

"As to the carburetor. I sent it out to be rebuilt 20 years ago to I believe a Jim Alexandro? He was highly recomended and was thought to be very exacting. One just dosen't know till the component is put back in service. And it did sit for 20 years. I believe it cost well over $100 then. I know that the prefered carb is the Stromberg. But I have tried to find one with the correct accessories for mounting with no luck." Unfortunatley I did not take detailed photos when I removed the carb so when I" hung" all the parts back on the engine prior to sending the car out to the shop. I relied on them find the correct placements on the linkage. Only detailed diagrams I have seen over the years in "The Torque Tube" were for Strombergs.

More on their evaluation..

"The carb was obviously rebuilt. The leather seal on the accelerator pump was very dry and "crispy" and there is some problem with the linkage that controls the stroke of the accelerator pump. Once the engine fires it runs well but it takes a lot of cranking to get it going since the accelerator pump doesn't squirt fuel into the bowl when operated via the pedal. There is also a vacuum leak around the butterfly shaft in the carb which doesn't help things. I suspect the shaft was marginal when the carb was rebuilt and the rebuilder deemed it serviceable but it should be rebushed for best operation".

I would like to get the car's carb problems smoothed out as soon as possible. Then I could tackle some of the detail work to to make it the reliable driver I wanted. Any input on my course of action once I get the car back? I do have a spare Marvel carb to rebuild. I have some seen posts on trouble shooting these Marvels. Directions? Ideas?Larry

Impatience is the enemy. There may be an internal adjustment to the throw of the accelerator pump but when a subassembly is presented as rebuilt and ready to go most shops are reluctant to mess with it for fear of being accused of "padding the bill". Likely the problem is a simple one but would take time to resolve and time is money. You might also want to look at the ends of all the linkages from accelerator to carb and manifold/choke to carb. Linkage end holes and pins worn from round and snuggly fitting to oval and sloppy fitting also interfere with fine adjustment and consistent operation. As always with restoration the Devil is in the details and there are always problems that surface after the car is reassembled, especially with parts that were rebuilt 20+ years ago such as carbs and fuel pumps.

Reading the above post, I have a 1937 Dodge D5, where the gas tank has no pickup line/tube. Anyone know what this looks like so I can mock one up and how it's attached please/

Welcome jmspeno,

I can't help you with your problem, but would suggest you start a new thread in a different section. I would recommend you start a thread in either the Dodge section further down or under the general section above instead of in a Buick forum. Hopefully you will have better luck finding someone who can help you. Good luck.