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Hard start when warm

Discussion in '40- & 55-Series Tech' started by mattcobb, Dec 15, 2003.

  1. mattcobb

    mattcobb

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    My cruiser starts great when cold. Full choke, one pump of the gas, and the key fire sit up right off. About 10 seconds there and then half choke. When it is warm it is really hard to start. It takes no choke and lots of throttle pumping and about 10-20 secinds of cranking to get it to go. It has an air pump and all smog is still on it. The engine is F, 74 fj40. Any thought on what is going on? Anything to make it better? (besides a better driver)
     
  2. Niner

    Niner

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    I've had a similiar problem but it was because when I would shut it off when warm the full pressure would push through the jets and basically flood the thing. I never fixed it just held it to the floor to start it when warm. to see if that is what is happening just take the air filter off when warm and shut the truck off and see if you see any seapage.
     
  3. theo

    theo

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    I have the same problem but I'm running a 350 with carb. I think my problem is the fuel line runs up past the exhaust manifold, so when it's hot and not running the heat causes vapor lock and I have to turn it over lots to prime the fuel line again.

    On the other hand, it should only take a couple of revolutions to fill the fuel line from the pump to the carb so I'm not so sure.

    But maybe vapor lock is hard to overcome?

    If you solve it let us know. And I'll reroute my fuel line soon and report back if it helps.
     
  4. Gumby

    Gumby Supamod Staff Member s-Moderator

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    Vapor lock should not be a problem with the stock carb 'cause it has a return line.