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1925 Marval Carb


carmover

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Just for future reference:

When adjusting the float for any reason on these older carbs with a cast brass float arm, try changing the thickness of the gasket beneath the fuel valve seat.

If changing the gasket thickness does not work, remove the arm from the float, and HEAT it in an oven before attempting to bend. After heating, bend no more than a couple of thousanths of an inch and allow to cool. Repeat as necessary. Patience is your friend.

Jon.

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Thank you.

There should have been a couple of extra wrapped with the fuel valve in the kit.

If you should need additional, NAPA stores (at least around here) have a fiber washer assortment. You can use thinner or thicker, or even stack two or three together to get a thicker total.

Jon.

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We have a bunch of Marvel stuff here, mostly 26-28 Standard. Can you give us measurements of the float arm? Length, distance between pin and either end of the arm, and pin diameter? We can probably help you. Repairing the original float arm can be done but would likely result in additional weight. Send an email for more info. Roger Barrett, BCA #99

bcanumber99@yahoo.com

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Roger I am betting that is the same part. Mine measures app 1 3/4" long The large end the needle screws into is around 3/4". The other end has a very small threaded hole where the screw goes through the float and screws into it.

The pin is 3/4 of an inch from the needle end and app. an inch from the float end.It looks identical to your spare float assembly when put together.

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  • 1 month later...

I bought the two carb bowls and float arms from Terry asembled everything with new needle and seat and float.I put the carb back on the car and turned on the fuel with the bowl cover off.fuel seemed to trickle in and filled the bowl to the correct level.I had measured the float level and set it to the correct height.With the fuel level up the float came up and shut off the fuel.It didn't flood but stayed right where it should be for about 30 minutes.It started quickly and ran well for a few seconds and started puffing black smoke and sounded like the choke was on.I got out and checked the carb float again and the float was all the way down and fuel was just trickling in and the needle was all the way up.The canister has plenty of fuel in it and seems to be working fine.I took the line loose at the carb and have a good flow there.I made a tool so I could take the float assembly out while the carb is on the car and when you remove the needle from the seat the fuel flows in fast.I took the plug out from under the seat and observed the needle and it was opening up like it should.I am totally frustrated.I do not have a clue.

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carmover

Sorry about your carb issues. Mine still seems to be holding its own. I still have to get the one I purchased on e-bay apart to inspect. I have had it soaking for about a week now. I will see if I can get it apart to consult as to your issues. Also I would like to compare to mine on the car since this one is supposed to be for a master.

Best of Luck:

Larry

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Your vacuum tank is not shutting off when it's full and gas is being sucked into the intake manifold. The symptom is exactly what you see. The car is running rich. Take off the vacuum line with the tank full and plug it on the manifold side. The car should run fine for a few minutes until the vac tank empties or you can reattach the line and suck more in. The float in your vacuum tank might be bad. Should not have gas in it. I had this problem on mine and seems like it's part of the initiation. Don't give up. You're almost there. I never had the problem again after I fixed it right. I had a 27 model 29 that I sold to my neighbor. It had this problem and I knew what it was right away. Fixed it and it was fine. He was afraid to drive this old car very far from home. These cars used to go across the country in much worse conditions. They are made to be maintained and repaired as needed. Owners manuals included the procedures and tool kits were supplied. You'll know your car very well soon enough. This is part of the experience. Now I feel like putting on my raccoon coat and going for a Sunday drive.

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After thinking about this for a while I think this might be the problem.I have 2 fiber washers under the seat which might be raising the seat up too much for the needle to open enough.I am going to take one of the washers out and see if this helps.I cleaned the canister and checked everything and installed one of Bob's kits and tested the float and it was in good shape.The canister seems to be doing what it is supposed to do.If it still runs rich I will try these suggestions.

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I have to agree with bubba, I had the same symptoms with mine (about 27 years ago) and fuel was being sucked into the intake via the vacuum line causing it to run rich. Could not figure that one out for a long time. I even resorted to flipping the intake and putting a down draft carb and an electric fuel pump on so I could drive it. Finally took a close look at the vacuum tank and found some small rust pin holes that I had to solder shut. It's been so long ago I can't remember where they were without taking it apart to have a look. It has been running well for a long time now. So if your double washers does not solve the problem take another look at the vacuum tank. Leon

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