Topic: 1951 Ford Custom 8 cyl EAB Carb backfire


DJ    -- 04-19-2017 @ 6:35 PM
  Made a problem worse. Engine was running pretty good. Had slight hesitation on acceleration around 50 mph. Concerning part was I saw signs of fuel leaking onto the intake. I bought a Walker Carb repair kit - 15302B. I disassembled everything, except the inlet check ball (laziness). Soaked in cleaner, brushed, and soaked again, wiped clean, blew out with compressed air. I did not replace the power valve or the spark valve because because the kit parts were not identical to the one on the Carb. There was also a spring under the accelerator pump piston. This spring was not pictured in the kit or in my shop manual, so I did not reinstall. I reassembled and have a consistent, pop, pop, pop, - backfire with black soot coming out exhaust. . I checked the vac hose to distributor. It was loose. I tightened up line, no change. I disassembled, set float to 1 5/16. Same consistent backfire. So my questions 1. Anyone know if power valve in kit will work in my Carb? 2. Should I put spring back under accel pump piston? 3. Open for suggestions. Thank you. DJ


TomO    -- 04-20-2017 @ 8:00 AM
  Signs of fuel leaking into the intake manifold can be caused by the power valve or the power valve gasket. Your engine is running rich now, which is likely caused by the power valve gasket leaking.

I have no experience with Walker carburetor kits, so I do not know if they supplied a correct power valve. The valve should open when the vacuum drops to 6.5 inches. It is open when the engine is not running. The gasket surface should be flat all the way to the threaded portion of the valve.

When I install the power valve, I use the thick gasket with the triangular cut out and tighten the valve hand tight. I assemble everything except the base and the top. Then I fill the float bowl with enough gas to cover the power valve and leave the body sit on clean paper towels to check for leaks. If there is a leak, I tighten the valve another 1/6 turn. I repeat this procedure until I can leave the body sit for at least 8 hours with out the fuel leaking out.



Tom


DJ    -- 04-20-2017 @ 8:21 PM
  Thanks Tom. I went ahead and installed the new power valve following your instructions. Runs much better. I ran out of time to test drive, but hope with a little fine tuning, I'll be back on the road this weekend.


ken ct.    -- 04-20-2017 @ 11:25 PM
  Tom I respect your opinions BUT the tri-angler hole gasket is the worst possible choice. Their composition is too soft and crush out when tightened.Use nylon or lead. Walkers kits have the rubber accelerator pumps,lousey needle and seat,and incorrect # PV. Also some manufactures PV's have a parting line from the molds they are made in they interfear with the gasket sealing. They must be trued and flat by turning down in a lathe like I do with mine. Only my 20 yrs experience doing these. ken's carbs. ct. The nylon ones Charlie NY makes are the best around and he modifies all my Daytona PV's in # 5.5 work much better than standard 7.5 ones every kit on the market contain. OMO.


TomO    -- 04-21-2017 @ 7:10 AM
  Ken,

I know that you have considerable experience in rebuilding the carburetors and people have had good results with ones that you have rebuilt, so I cannot dispute your comments, in fact I agree with your comments when the power valve has been machined to accept the nylon or lead gasket.

The power valve in most after market kits will not leak using the triangular cutout gasket, tightened in the manner that I described. Very few of them will not leak when the thin gaskets provided in the kit are used.

Tom


ken ct.    -- 04-21-2017 @ 2:32 PM
  Tom, I have had more trouble with the TA gaskets than any other,so stopped using them yrs ago. I use Charlies nylon ones exclusively and never any trouble.The Holley LEAD ones are hard to find and only have a few of themin my stash,LOL. Thanks for the comments,have a nice day,here its raining ugg. ken ct.


DJ    -- 04-22-2017 @ 4:00 PM
  Thx guys, I'm learning a ton about my car from you. I did use the kit PV and triangular gasket, but went with the existing accelerator pump, needle, and seat. Ken, I'll be in touch to get my next rebuild kit. From reading here and other sites, I was pretty sure my starting problem was caused a bad power valve. She is starting and idling beautifully now.


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