| nelsonford | -- 04-21-2013 @ 1:03 PM |
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I have had Dual Carb (94's) with the Ford mechanical pump on my 48 Merc for years and resently started having trouble with Vapor lock. With clear plastic fuel lines I can see the bubbles form and not allow gas to flow. I am trying to eliminate all the possible problems. I have a fuel regulator and am wondering if I need it and whether it may be plugged. I don't want to use an electric fuel pump unless absolutely necessary. I am installing a pressure gauge between the pump and fuel block. I will insulate fuel lines better and put shields where needed. Any suggestions?
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| supereal | -- 04-21-2013 @ 2:24 PM |
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Most "vapor lock" isn't. It is more likely that you have an air leak between the tank and the engine. We are seeing more fuel problems with ethanol added, and if you have any non-resistant rubber parts in the system, one or more may have been attacked. This includes the fuel pump diaphragm and valves. If you have any inline fuel filters, particulary made of plastic, look for cracks. Even though you see bubbles in the line, a failing coil or condenser will produce symptoms oftem mistaken for "vapor lock", as will a cracked flex line at the firewall
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| nelsonford | -- 04-21-2013 @ 2:33 PM |
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Thanks Supereal, I will look for possible leaks...One thing that comes to mind is the glass fuel pump bowl gasket. I understand it should be neoprene rather than cork.
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| supereal | -- 04-22-2013 @ 6:15 PM |
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Could be either. Most were originally cork, which tended to dry out and split. If rubber was substituted, be sure it is nitrile, which is alcohol proof. If the gasket is leaking, you probably found the source of bubbles.
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| TomO | -- 04-24-2013 @ 7:31 AM |
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The rubberized cork gasket material sold by Fel-Pro works great as a gasket for the sediment bowl. Tom
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| nelsonford | -- 04-25-2013 @ 4:37 AM |
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Tom Rubberized Cork sounds like a great idea. I'll give Felcro a try. Thanks again
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| nelsonford | -- 04-25-2013 @ 4:52 AM |
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I also checked and found the line runs within a few inches of the exhaust pipe and muffler. I am ordering some tubing good for 750F from Napa made by "thermosleeve" ($7/ft) which I will slide over the line. I can also put heat shields on the pipe.
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| joe b | -- 04-25-2013 @ 6:39 AM |
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While you are at it you should replace the plastic fuel line to the carbs. Plastic fuel lines are just waiting for an under hood fire.
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| Old Henry | -- 04-25-2013 @ 8:13 AM |
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The way I finally diagnosed vapor lock as my problem was every time I had a problem I poured cold water on my fuel pump and it fixed the problem. As soon as I became a "believer" in that phantom vapor lock I installed a backup electric pump back by the gas tank to switch on whenever the engine sputtered, died, or wouldn't start and it fixes it every time. It could be any of the other things suggested but don't discount vapor lock as the real problem easily diagnosed and easily fixed. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 4-25-13 @ 8:16 AM
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| supereal | -- 04-25-2013 @ 9:44 AM |
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I went thru that whole thing OH. As the problem got progressively worse, I decided to check the only part of the fuel system that I hadn't tackled: the fuel line between the tank and the firewall. I found it to be almost completely blocked with dirt and rust. What fuel did get thru seemed adequate, but on a heavy pull, it wasn't. My electric pump would smooth out the bucking, etc, until there was no more room in the line. Twenty bucks for a new line finally fixed it.
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| nelsonford | -- 04-25-2013 @ 11:01 AM |
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Joe B Did you mean change them keeping them plastic or to steel?
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| nelsonford | -- 04-25-2013 @ 11:18 AM |
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OH Thats not a bad idea adding an electric pump. What make did you buy...I understand you dont need a pressure gauge with Carter In-line pump 2-4 lbs?
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| Old Henry | -- 04-25-2013 @ 1:07 PM |
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The problem with the Carter pump is that it does not allow flow through by the mechanical pump when the electric pump is not on. Most that need that feature use the Airtex. But, even the Airtex 2.5-4 psi pump exceeds the 3.5 psi limit of the carb float valve so I had to add a holly pressure regulator to keep from flooding the carburetor bowl. If the electric pump is just used momentarily to prime the electric pump when it's vapor locked the pressure regulator probably would not be needed. But, any continuous use it would. Airtex E8011 for 6 volt available here: http://www.ebay.com/itm/6-VOLT-FUEL-PUMP-LOW-PRESSURE-PRIMER-PUMP-OR-FUEL-PUMP-2-5psi-4psi-25gph-30gph-/310638236668?pt=Vintage_Car_Truck_Parts_Accessories&hash=item48537b53fc&vxp=mtr#ht_1131wt_919 Airtex E8016 for 12 volt here: http://www.ebay.com/itm/UNIVERSAL-ELECTRIC-FUEL-PUMP-2-5psi-4psi-INLINE-EXTERNAL-30gph-12v-AIRTEX-E8016s-/230958427823?pt=Motors_Car_Truck_Parts_Accessories&hash=item35c631eeaf&vxp=mtr#ht_446wt_986 Holley pressure regulator here: http://macsautoparts.com/early-v8-ford-mercury-fuel-pump-pressure-regulator-holley-1-4-psi-3-8quot-npt-ford-9500-reg/camid/F30/cp/JS0R3CHL1140518/ Photo of my pump installation attached. Old Henry (The older I get, the better old looks.)
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| supereal | -- 04-25-2013 @ 2:52 PM |
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We use the inline electric pumps sold by C&G. They allow flow thru so the mechanical pump can be used without the booster. The proper fuel line is the copper coated line. C&G sells the complete line with fittings included. The original 1/4 inch line is just big enough, and any blockage mimics the fabled "vapor lock". The ethanol in today's gas both allows moisture to attack voids in the copper coated steel, and dissolves crud in the tank that blocks flow.
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| Old Henry | -- 04-25-2013 @ 8:52 PM |
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C&G sells the same Airtex pumps I was talking about but for $10.00 more for just the pump without the filter then you have to buy the filter seperate for another $10.00. So, $20.00 more than you can get them on ebay. Old Henry (The older I get, the better old looks.)
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| joe b | -- 04-27-2013 @ 6:24 AM |
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Nelson I meant to get rid of the plastic lines. They are just asking for trouble.As an aside, back in the '60's,when we were all cruising we had some cops on motorcycles called "The Flying Squadron" who would pull us over on Saturday night and check the car. Two things they looked for in particular was proper bumper height and plastic fuel lines. Plastic lines got you towed to the impound lot.Under hood fires from these was quite common.
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| supereal | -- 04-27-2013 @ 8:53 PM |
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That thing at the rear of the Airtex pump is a check valve. It comes with the pumps we have bought from C&G. They may have changed the pumps since our last purchase, as they now offer a separate filter. It is always good practice to put an inline filter between the pump and the tank, in any case. This message was edited by supereal on 4-28-13 @ 10:47 AM
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| Old Henry | -- 04-28-2013 @ 12:11 PM |
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"That thing at the rear of the Airtex pump is a check valve." Funny you should say that because that's exactly what I thought and said until someone told me different and I saw that device sold seperately as a filter. I think the instructions to the pump even say that the warranty is void if the filter is not used in front of the pump. We lives and we learns. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 4-28-13 @ 12:13 PM
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| supereal | -- 04-28-2013 @ 12:58 PM |
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I don't know why they would call it a "filter", as it seems to be too small to be effective. When we bought our first one, I figured it was a filter of some kind, but upon checking further, it functions as a one way check valve. I assumed it was to make the pump more efficient. They are good pumps, anyway. If, in fact, such a "filter" is required, it begs the question "why not include it"? In the new C&G 57-72 catalog, it specifically shows it as "electric fuel pump replacement filter", but goes on to say it only fits the 12 volt pump. This message was edited by supereal on 4-28-13 @ 1:04 PM
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