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Holley carb "loading" |
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keuka1 
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Joined: August-31-2004 Location: United States Status: Offline Points: 25 |
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 Topic: Holley carb "loading"Posted: June-06-2005 at 11:07am |
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Hey I was hoping someone here could help with an issue I have with my 1985 Martinique with a 351 and Holley carb.
After "putting" around or idling for about 30 minutes. WHen I try to pull up a skier the engine backfires through the carb and take about 5 minutes to run normally. Any iseas on what I can do to correct this> Thank you. |
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Jim_In_Houston
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Joined: September-06-2004 Location: United States Status: Offline Points: 1120 |
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Posted: June-06-2005 at 11:26am |
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Mine did the same thing. I found that after running hard and then going to an idle you could look down into the carb and see fuel dripping into the manifold. I called the carb rebuilder and was told the needle valve was sticking. In my case it turned out to be junk in the float bowl that appearantly interfered with the needle valve being able to close. It was suprisingly easy to remedy. I removed the carb, removed the float bowl, cleaned out the junk (it was a dark fine powdery substance), reassembled, installed an in-line fuel filter and the problem has not returned.
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Happy owner of a '66 and a '68 Mustang
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jameski
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Joined: May-18-2004 Location: United States Status: Offline Points: 368 |
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Posted: June-06-2005 at 11:47am |
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Also, check your idle mixture enrichment screw adjustment. If your mixture is too rich, it will foul your plugs and cause these symptoms. Do you see any black smoke coming from your exhaust when you are idling?
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keuka1
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Posted: June-06-2005 at 11:57am |
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I do think it is running a little rich via black smoke.
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79nautique
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Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Posted: June-06-2005 at 2:21pm |
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You most likely will need to replace the power valve since it backfiresd thru the carb.
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Tim D
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Joined: August-23-2004 Location: United States Status: Offline Points: 2641 |
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Posted: June-06-2005 at 3:25pm |
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Yeah, one backfire, replace the power valve, that's the one on the inside which screws into the metoring block. I wouldn't rule out a intake leak also.
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Tim D
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79nautique
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Posted: June-06-2005 at 5:50pm |
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Well actually I would re-build the carb, it's backfiring (lean condition and/or bad power valve) and then it also has black smoke coming out of the exhaust (rich condition) and takes awhile before it cleans out and runs right which could very well be fouled spark plugs.
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JEFF KOSTIS
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Joined: April-19-2005 Location: United States Status: Offline Points: 817 |
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Posted: June-07-2005 at 1:20am |
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Aside of the issues listed which are certainly correct, make sure the points(if you have them) are not pitted. Idling for long periods causes the points to track (short themselves out) with a carbon track. They are open/close slowly at idle and doesnt take much spark to run ok. When you hit the gas, the carbon track partially shorts the points and screws up the dwell until the engine is reved to chatter the points clean. My boat does it after idling great for a while(get about 100 hrs per set of points) and just pain dies, but im quick on the gas to release before it backfires. Changed points, all ok!!
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keuka1
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Posted: June-10-2005 at 5:39am |
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Thanks for the feedback.
I think I will start with the cheaper stuff...points, plugs, cap, rotor, coil (maybe) condenser and see how it goes. IF that doens not help the porblem then it will be time for a carb rebuild. Again thanks for the help! :) |
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SS 201
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Joined: October-20-2003 Location: United States Status: Offline Points: 232 |
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Posted: June-10-2005 at 7:41am |
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Fords are from the factory 8 degree retarded, as the chain wears it gets more retarded. A backfire thru the carb indicates its on the intake side of the engine,timing,intake valve etc..
Although previous events mentioned are true, Check the timing at 2500 and it should at least be 32 degrees. Whatever the inital is is meaning less the full out timing is. |
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keuka1
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Posted: August-11-2005 at 3:16pm |
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Changed T stat and it is now running at 140 and the carb is not "loading" or backfiring throught the carb any more.
But since I had a few backfires throught the carb I will need to change the powervalve. ANy thoughts on how hard this is to do? Thanks for the input. |
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skyhawkflyer
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Joined: February-08-2005 Location: Zimbabwe Status: Offline Points: 275 |
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Posted: August-11-2005 at 3:40pm |
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If it's running OK and you don't notice any problems through mid throttle leave it alone.
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Siveck
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Posted: August-12-2005 at 12:59pm |
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The power valve is in the front metering block on the carb which is behind the front fuel bowl. You can actually change it without removing the carb. Just unhook the fuel line and remove 4 bolts on the front and you will find it in the metering block. You might need a gasket set though. If you get a gasket set, then you might as well rebuild it. It's really quite simple. And you could even add the check valve kit from Holley that supposedly protects the power valve during a backfire. I added that check valve and its nice to know that maybe my power valve is still good after a couple of backfires while getting the timing right. The correct power valve is a 6.5".
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1975 Ski Nautique
"Small Letter Boat" |
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JAG459
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Joined: August-12-2005 Location: United States Status: Offline Points: 61 |
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Posted: August-12-2005 at 6:32pm |
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There is another carb problem that can cause a rich mixture that is usually overlooked. Inside the low speed float bowel of the carb there is a tube with 2 orings on it that connects the metering block to the carb body. If these orings are not tight fitting it can result in excess fuel to be drawn into the low speed curcuit. As the orings deteriorate it will cause the engeine to run in an ever increasing rich condition. At its worst you will see fuel coming from primary orifices in the carb throat at an idle. The orings are include in rebuild kits.
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GottaSki
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Joined: April-21-2005 Location: NE CT Status: Offline Points: 3363 |
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Posted: August-12-2005 at 8:29pm |
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I agree TJ, the PV is not nearly as fragile as I've heard described.
Witnessed many boats and a 4150EG on a Loadmaster pop repeatedly for poor ignition or lean setup with no ill effect to the PV. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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