hard start /carb issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dadsredwagon · 11-27-2010, 11:43 PM

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

**slepysal** · 11-28-2010, 12:03 AM

Hows the fuel filter? Do you have a manual or electric choke?

62ShortStep · 11-28-2010, 03:03 AM

An internally leaking fuel pump may work at higher RPM's, but may not be able to pump anything at low speeds.

'63GENIII · 11-28-2010, 11:33 AM

Quote:

Originally Posted by 62ShortStep

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.

'63GENIII · 11-28-2010, 11:37 AM

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?

Dadsredwagon · 11-28-2010, 01:08 PM

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..

'63GENIII · 11-28-2010, 05:29 PM

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.

SiCk_DiAbLo · 11-28-2010, 03:08 AM

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!

62ShortStep · 11-28-2010, 08:13 PM

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.

11-27-2010, 11:43 PM	#1
Dadsredwagon Registered User Join Date: Aug 2006 Location: Spring,TX Posts: 342	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

11-28-2010, 12:03 AM	#2
slepysal Registered User Join Date: Oct 2006 Location: San Jose NOR*CAL Posts: 3,080	Re: hard start /carb issue Hows the fuel filter? Do you have a manual or electric choke? __________________ 1960 Apache long bed fleet L6 250 Clifford intake 2 bbl carb. Langdon cast headers with dual exhaust and bellflower tips. T-5 5 speed, power steering and power disc brakes. "Over, Around or through it... "

11-28-2010, 03:03 AM	#3
62ShortStep Registered User Join Date: Sep 2010 Location: Fountain Valley, CA Posts: 179	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.

11-28-2010, 11:37 AM	#5
'63GENIII Registered User Join Date: Sep 2008 Location: San Carlos, Ca. Posts: 3,048	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? __________________ Chris '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

11-28-2010, 01:08 PM	#6
Dadsredwagon Registered User Join Date: Aug 2006 Location: Spring,TX Posts: 342	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..

11-28-2010, 05:29 PM	#7
'63GENIII Registered User Join Date: Sep 2008 Location: San Carlos, Ca. Posts: 3,048	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. __________________ Chris '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

11-28-2010, 03:08 AM	#8
SiCk_DiAbLo Registered User Join Date: Oct 2008 Location: Norfolk,Va Posts: 354	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! __________________ 1993 Chevy Silverado. 1984 Chevy Z28. 1972 Chevy Custom 10. 1965 Custom 10..FOR SALE

11-28-2010, 08:13 PM	#9
62ShortStep Registered User Join Date: Sep 2010 Location: Fountain Valley, CA Posts: 179	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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