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Discussion Topic:
Runs better with choke out?
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Flatbob |
04-24-2010 @ 11:42 AM
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Member
Posts: 437
Joined: Oct 2009
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My '36 runs much better when driving with choke about half way out. Is this an indication of fuel starvation? Do I need to raise float level, it's now 1/4" from top of casing? Have new fuel line & gas tank with rebuilt carb. Any suggestions would be appreciated.
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supereal |
04-24-2010 @ 12:14 PM
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Bob: From your description, it is a good guess that there is a fuel supply problem, either in delivery or in the carburetor. Carb level should be carefully set. I've attached a copy of the gauge we use. Remove the top of the carb, turn it over, and place the gauge over the float. The float should just touch the gauge. Check delivery by disconnecting the fuel line at the carb and placing it in a container. When cranking the engine, there should be an ample stream of fuel. You don't mention replacing the fuel pump, or whether you have cleaned the carb and examined the jets, as well as the float needle and seat.
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Flatbob |
04-24-2010 @ 12:32 PM
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Super, it's a new fuel pump, will check the pump for output. If nothing else, this carb. is clean; I've taken it on & off several times & always dismantle & clean, will check the jets again. Will let you know what I find. Thanks
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TomO |
04-25-2010 @ 8:04 AM
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Flatbob, Fuel delivery can be caused by a plugged line, a vacuum leak, weak fuel pump or worn push rod. If you have a new Airtex fuel pump, that could be your problem. I have had a couple of them where there was enough play in the operating arm that they could not deliver the correct amount of fuel. To check fuel delivery, disconnect the fuel pump line from the carburetor and direct it into a graduated container. Crank the engine long enough to get 2 ounces of gas in the container and then continue cranking for 15 more strokes of the pump. The pump should have delivered 6 more ounces of gas.
Tom
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37RAGTOPMAN |
04-25-2010 @ 8:34 AM
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FLATBOB if the pump does not pump the right amount, you should also check the line running to the tank, you could hook a test fuel tank [ A OUTBOARD FUEL TANK works good for this purpose ] and see how it runs with that one verus the tank in the car, this will rule out the line from the tank to the flex line up front, it will not pump if it can not pick up the fuel, Hope this helps 37RAGTOPMAN
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Flatbob |
04-25-2010 @ 9:00 AM
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Posts: 437
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Here's a picture that may explain the problem. As you can see in the photo the fuel pump screen is loaded with debris, stuff that looks like coffee grains and a piece of white material as well. I installed a new Drake gas tank a few months ago so would like to believe it's not rust. Just before my problems started went to gas station with 2 gallon can filled it up and put it in the car; don't trust my fuel gauge. Could this be dirty fuel from the station. Would installing temporary filter up on firewall where the flex line is be an easy solution till I run the tank dry?
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supereal |
04-25-2010 @ 9:08 AM
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These days, fuel contamination is a big problem. Last week, we had three cars in our shop with bad gas, all purchased at the same station. It is a very good idea to install a fuel filter in the gas line as close to the tank as possible. Even then, fuel contaminated with water will cause problems. The worst we've seen was when liquid fertilizer was accidentally put into a filling station's tank. I'd drain the tank. It is also possible that someone put a handful of dirt in the tank. A locking cap is very good insurance against that sort of thing.
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Flatbob |
04-25-2010 @ 9:25 AM
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Super, I do have a locking gas cap. Will drain the tank, disposal is the biggest problem. Don't normally run an inline filter as I would like to show the car at EFV8 meet & I don't think you can have something like that, but I understand you can have seat belts so maybe the filter would be okay.
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supereal |
04-25-2010 @ 10:29 AM
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I don't show my cars, so having a filter isn't a problem. I have been marooned with fuel problems in the past, so the filter is a kind of "insurance". The stuff in your photo looks a great deal like the material we routinely find in gas tanks, but doesn't look like anything that would result from installing a new tank. I suspect that much of the bad fuel results from stations running their storage tanks down to the bottom where crud accumulates. Most pumps have filters that are supposed to catch contamination, but only if they are serviced regularly. In addition, at least around here, the operators are supposed to test gas for water. There is a product called "DeTex" which is a test strip. If you buy your fuel at the same place regularly, I'd ask them if they test their gas. Contamination can be very expensive in new vehicles, as it can ruin the in-tank high pressure pump. If that pump has a filter "sock" on it, the whole unit usually must be replaced, which is expensive, to say the least. Installing a temporary filter is a very good idea, as draining doesn't always get all the loose material. We put bad gas thru a filter of the type used in body shops for paint so we can identify the particles. Usually, the gas station is stuck with the repair bill in this area.
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Flatbob |
04-25-2010 @ 7:11 PM
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It all came back to me while I was sitting at my workbench cleaning out fuel pump. As I said before I replaced fuel tank because it was full of rust & removed fuel pump and put it in the shed & replaced it with another. A few days ago car started running badly so thought maybe the fuel pump was bad so replaced with previous pump, yes then dirty one. Cranked half a cup of fuel into jar with no debris, put clean pump on & runs great. Here's what came out of dirty pump.
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