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Carb swap


jcritt1

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I have a 305 mercruiser/gm 230 hp with a Rochester 4 bbl quadrajet and have been having issues with it for the past couple seasons. I did rebuild it last season early on but still having problems. I can't really pinpoint the exact problem but typically it starts and runs fine till you shut down then it's extremely tough to get started again. I guess my question is should I consider swapping the carb to a new one or take it to someone and have it gone through by someone who truly knows what they are doing? Any recommendations would be greatly appreciated. I just want it to run well and start when I want it to not when it wants to. Again thanks in advance for any input.

 

 

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Sounds like maybe a choke issue.  Have you tried setting that to spec and actually watch it open up as it warms up and close as it cools down? Otherwise if it's still in good condition and the metal is not starting to breakdown then I would take it to a local race type shop and have it rebuilt if the total quote is around 200.00  Otherwise I would go new -Jegs.com and ebay have them for around 325-400 if I remember correctly. Edelbrock makes s great carb as well.Might be able to find one cheaper if you spend some time on Google etc.

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My nephew in FLA works for a marine guy who specializes in carb rebuild.Does a lot of them on big boats.  Apparently he takes the carb and imerses it in Gumout for a day or two(says thats the secret) , blows it out with compressed air and the rebuilds it. Fixes carbs other guys can't. 

 

Or maybe it is not hooked up/ adjusted  correct. Could be a lazy choke. Just a guess . 

Edited by HB2
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Real Stories is right. Check everything leading up to it closely as well as the choke plate coming fully open when the engine is warm as Bob B said above. A lot of Q Jet problems actually aren't the carbs fault but the little things leading up to it. If I can help you out feel free to pm me. A properly tuned Q Jet will out preform about any marine style carb out there including the troublesome Edelbrock/Hollys. Especaly in the low RPM trolling area. 

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The QJ carb is an excellent carb if kept in good condition. I have rebuilt many of these over the years and one issue I continually run into is the body well plugs on the bottom plate seeping. Every QJ rebuild that has these plugs gets a coat of epoxy before assembly on  to eliminate that issue.

Edited by JAYRFRED
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