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  1. #1

    Exclamation Carburetor Hot Start issues

    Is anyone having an issue with your car not wanting to restart after driving it for more than 30 minutes? I have a 84 GT convertible that has a stock block 302 with all aftermarket parts bolted on. I have a Eldebrock RPM Intake and a 650 Holley. I have a MSD 6AL and MSD distributor.
    I have BBK Long tube headers. I have a 2 1/2 cowl hood with a vent in back. I have a 1 spacer on the manifold and a Holley aluminum heat shield under the Carburetor. I am running an electric fuel pump and have a return line to the tank.
    I have talked to Holley and they said they are hearing of this problem and they say it is the ethanol in the gas we are getting today. They say that the gas is formulated for fuel injected cars of today.
    Does anyone have any resolutions or know of any additives that can be added to the gas each fill up?
    I have had my car 20 years and this just started last year. It is a real problem on cruises or trips out of town.

    Any help with this would be appreciated.
    Thanks, Rich Rudolph, Jr.

  2. #2


    I had an issue like this, switched my 1" aluminum spacer to a Phenolic plastic one and the issue went away.
    It never wanted to start when hot, let it sit for 1/2 an hour and it would start right up.

  3. #3


    I have also replaced my 1” spacer on top of the manifold with a Phenolic spacer.

  4. #4
    FEP Super Member gr79's Avatar
    Join Date
    Jun 2009
    SE Michigan


    First off, am using regular grade ethanol fuel bought pretty much wherever and whenever needed.
    No additives added.
    When a decent station with low price is found, tank is topped off soon after low fuel light is on.
    Have vac/boost gauge to monitor engine. Stock 79 2.3T.

    Had similar problem suddenly appear April 2006 Michigan climate.
    Drive to store, parked in asphalt parking lot. Above average warm day for April.
    Shop, come out, car acted as if flooded.
    Next chance parked and before starting, pulled air cleaner lid and looked deep into carb at throttle plates
    Plates were shiny wet with fuel. Noticed fuel drip into venturis. Restarted using flooded engine procedure.
    Different model carb (Holley 5200) but in this situation, a carb is a carb.
    After problem(s) were found, started normal again consistently. Cost=zero

    Reconnected charcoal canister vac lines. This was an ongoing experiment as to what worked best.
    May have reconfigured a intake or carb vac line or two but have no detailed note on that.
    Also reset float level. Prob gave carb passages a little cleaning too while in there.
    Carb bowl may have emptied from dripping and needed cranking to fill back up.

    Now have a Holley 2300 series 2v, manual choke, mech pump, fuel return. Great carb.
    Once warm, restarts immediately all weather no pedal faster than the 2.3 EFI in my Ranger. Click, zoom.
    Steady idle vac and rpm.

    At this time of year in cold winter climates, fuel blends may mismatch weather, can make engine act weird.
    Winter blend, spring, summer blends. No way to really know what is in the station storage tanks.
    Or if car is not driven much, what is in the tank and for how long.

  5. #5


    I agree with the Phenolic spacer. I've done same and yes it works perfect.

  6. #6


    Have you checked the float levels? (When's the last time the carburetor was gone thru? - float/fuel levels rise as needles and seats wear, and would increase any negative affects that potential percolation is doing...) What's the fuel pressure at? Ignition timing?....
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website --->

  7. #7


    A warm April day in MI you probably still had winter gas and therefore a lower boiling point.


  8. #8
    FEP Super Member gr79's Avatar
    Join Date
    Jun 2009
    SE Michigan


    Yes winter mix. The canister reconnection to carb vent compensated on the stock carb.
    Planned a trial triage next time it happened. Venturi drip stopped. No problem since.
    Current Holley does not drip. No canister connection on this one.
    Winter mix seems to help fuel mileage when an unusually warm spell occurs.
    Updated seasonal blend is best found from a station with high volume sales.
    Have gone back to same station to get the last of the winter batch.
    Reverse is true in a fall cold weather snap, summer gas.

  9. #9


    Have you tried a tank of ethanol free gas in it to see if it starts better? I exclusively use Wawa ethanol free gas. I add Startron when I must fuel up with ethanol blended fuel. I notice a difference in performance and exhaust odor.

  10. #10
    FEP Senior Member liv2roc's Avatar
    Join Date
    Jul 2009
    Cherryville n.c.


    plastic spacer fixed mine

  11. #11


    Have you checked your EGR valve for leaks? It could be stuck or letting in air thru the diaphram leaning out the mixture and maybe a hard start. You can spray the diaphragm, at idle with carb cleaner and check for leaks or idle speed changes.

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