Cliff's Quadrajet Parts and Rebuild Kits
Quadrajet Problem Solving => Diagnose a Quadrajet carburetor problem => Topic started by: Ligfishing on August 19, 2015, 04:12:58 PM
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Sirs:
Marine installation with twin Chrysler 5.9 circa 1989. Qjet carbs. somewhere along the line port carb was changed removing the base plate to one without a 3/8" vacuum port. found a base plate with the port from a doner carb. after reconnecting and making the PCV function again I find fuel economy is down 25% but fuel burn matches other engine.
If PCV system is costing me 25% I'll disconnect on both engines.
LIGFishing
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PCV is a controlled vacuum leak, so it will add some air to the engine and lean it up slightly.
I have never seen a Marine engine that used it, or a carb that was set up for it, but I suppose they may have used PCV in a few applications.
It's actually a good idea, especially if the boat is used under light to moderate load a lot, as PCV would burn off the crankcase vapors produced like an automotive application.
What may also be happening on this new fuel is that the engines want a richer mixture, and the carbs are a little lean right to start with, so they don't want or like the additional air from the PCV system.......Cliff
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Thanks Cliff!
I saw my parts are on the way!
Your customer service is second to none-
Cant wait to dive into those carbs and Rebuild.
I'm hoping they outperform the ones in use now and I can get my mileage up a bit.