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Old 11-27-2010, 11:43 PM   #1
Dadsredwagon
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hard start /carb issue

Had not started the truck in three weeks, 1965 230 motor I do the old pour some gas in the carb she fires up runs rough but is ok, I shut it off wait an hour same thing. I bought a rebuild kit for the carb replaced the accelerator pump and still seems like it's not pumping gas, get it started with pouring gas in the carb, will fire up right away, can floor it and will be fine. any thoughts?

thx
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Old 11-28-2010, 12:03 AM   #2
slepysal
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Re: hard start /carb issue

Hows the fuel filter? Do you have a manual or electric choke?
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Old 11-28-2010, 03:03 AM   #3
62ShortStep
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Re: hard start /carb issue

An internally leaking fuel pump may work at higher RPM's, but may not be able to pump anything at low speeds.
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Old 11-28-2010, 03:08 AM   #4
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Re: hard start /carb issue

I have the same in my truck, popped the carb open, the float pin was stuck on mine..Cleaned it up and it was fine!
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Old 11-28-2010, 11:33 AM   #5
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Re: hard start /carb issue

Quote:
Originally Posted by 62ShortStep View Post
An internally leaking fuel pump may work at higher RPM's, but may not be able to pump anything at low speeds.
That's what I'm thinking. Need to put a gauge on it to check the pressure.
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Old 11-28-2010, 11:37 AM   #6
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Re: hard start /carb issue

Then again, usually the pump (when leaking), will get some fuel leaking through the hole in the casting that is there to let you know when it's leaking. I'd still check it with a gauge though. Does any gas come from the squirter when you blip the throttle with the engine off? Accelerator pump? No fuel in bowl?
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'63 k15 long step
Vortec 7.4 - L29 Blackbear tune, Five 0 Motorsports injectors, Chris Straub Cam, NV4500, divorced 205
52" front and 63" rear spring swap
D44 / 14bff - disc axles
Milemarker 9K and 10.5K hydraulic winches

63" & B52 Spring Install http://67-72chevytrucks.com/vboard/s...ng+swap+thread


NV4500 Reverse Build Thread http://67-72chevytrucks.com/vboard/s...=reverse+build

L29 - 7.4 Vortec Build http://67-72chevytrucks.com/vboard/s...&highlight=L29
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Old 11-28-2010, 01:08 PM   #7
Dadsredwagon
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Re: hard start /carb issue

no choke used , do not see any fuel from the squirter, , when I removed the top have there was some fuel in it, I see if I can borrow a fuel pressure tester, what should the pressure be at?

thx all..
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Old 11-28-2010, 05:29 PM   #8
'63GENIII
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Re: hard start /carb issue

Pressure should be at @ 4-6psi but if you're not getting anything from the squirter(s) and there is fuel in the bowl then I would say it's likely accelerator pump issue. Sometimes there is a check ball in those things that gets stuck not letting the accelerator pump build pressure.
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'63 k15 long step
Vortec 7.4 - L29 Blackbear tune, Five 0 Motorsports injectors, Chris Straub Cam, NV4500, divorced 205
52" front and 63" rear spring swap
D44 / 14bff - disc axles
Milemarker 9K and 10.5K hydraulic winches

63" & B52 Spring Install http://67-72chevytrucks.com/vboard/s...ng+swap+thread


NV4500 Reverse Build Thread http://67-72chevytrucks.com/vboard/s...=reverse+build

L29 - 7.4 Vortec Build http://67-72chevytrucks.com/vboard/s...&highlight=L29
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Old 11-28-2010, 05:34 PM   #9
Dadsredwagon
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Re: hard start /carb issue

thanks 63GenIII, I replaced the accelarator pump in the new rebuild kit, I'll check the ball thing again and start again on the rebuild, is there any carb diagrams out there to look at?

thx so much!!!
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Old 11-28-2010, 06:22 PM   #10
'63GENIII
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Re: hard start /carb issue

I'm not sure of a diagram, hopefully someone will chime in here. I'm just speaking from general carb experience. Is there enough fuel in the bowl..like half full or just a small puddle in the bottom? Half full I would say acc. pump. Puddle, I would say fuel pump. If you take the fuel line off the carb and crank it over (make sure spark is disconnected and you have something to catch the fuel that may come out of the line) to see if there is sufficient fuel coming out. It should only take a couple cranks to at least see if there is fuel being pumped. This should help break the problem down to accel. pump or fuel pump without having a gauge handy.
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'63 k15 long step
Vortec 7.4 - L29 Blackbear tune, Five 0 Motorsports injectors, Chris Straub Cam, NV4500, divorced 205
52" front and 63" rear spring swap
D44 / 14bff - disc axles
Milemarker 9K and 10.5K hydraulic winches

63" & B52 Spring Install http://67-72chevytrucks.com/vboard/s...ng+swap+thread


NV4500 Reverse Build Thread http://67-72chevytrucks.com/vboard/s...=reverse+build

L29 - 7.4 Vortec Build http://67-72chevytrucks.com/vboard/s...&highlight=L29
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Old 11-28-2010, 08:13 PM   #11
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Re: hard start /carb issue

I think your on the right track 63GENIII. But since it runs okay when he has it floored, I don't think its the accel pump (I was wrong once before though)

If the fuel pump has an internal leak at one or both of the fuel pump check valves it would tend to give the symptoms he's describing. There would be no external leaking though.

Dadsredwagon- Follow 63GENIII advise and just see if fuel flows out of the fuel line leading to the carb. At cranking speed it should move about 1/2 cup gas in just a few engine turns.

Last edited by 62ShortStep; 11-28-2010 at 08:16 PM.
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