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JD_13
Joined: 30 Mar 2009
Posts: 7
Location: SC
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 Posted: Mon Mar 30, 2009 12:07 pm Post subject: HELP ME PLEASE |
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I moved up a class and could change the intake, exhaust, and carb. Last year I had to run all bone stock parts. This year I am running a four barrel Victor Jr. intake w/adapter plate. I bought a Holley 500 two-barrel #4412 during the off season. I was supposed to be able to bolt it on and go. When I rev it up from idle it hesitates right off of idle. I have set the idle mixture, I bought a new fuel pump, I checked the accelerator pump setting, I've checked for vacuum leaks, I checked my distributor advance. I also tried to find some troubleshooting articles online. They are mostly generic carb. articles and haven't helped much. Does anyone else run this carb.? Anybody got any suggestions? Any advice would be greatly appreciated.
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J.D. Green
#13 Charger Class - DIRT
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KBM17g
Joined: 23 Mar 2009
Posts: 174
Location: Michigan
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| Posted: Mon Mar 30, 2009 7:40 pm Post subject: |
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Watch the squirters as you go from idle to higher RPM's and see what it's doing. Is it dumping to much fuel in there and choking it or is it not dumping enough fuel for the carb to keep up with the engine?
Racer 96m would prolly be the best one to answer....well Randy could to I believe.
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JD_13
Joined: 30 Mar 2009
Posts: 7
Location: SC
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| Posted: Mon Mar 30, 2009 11:39 pm Post subject: |
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I worked on it some this afternoon. I adjusted the accelerator pump and also fine tuned the idle mixture. I also figured out that idle is not part of the problem. Any time I give it a sudden rev it hesitates. I can hold it up at 2 or 3 grand and then rev it and it still hesitates. After tuning today the hesitation isn't quite as bad, but it still isn't right. I watched the squirters and they act just like I am describing the engine. The first millisecond I pull the throttle they aren't responding. Then they squirt just fine. It is a super quick hesitation. I know that sounds like I'm being anal about it, but I borrowed a friend's Holley exactly like the one I bought and ran it the last race of the season and I didn't have a bit of trouble from his. My brother-in-law also runs a 500 and his doesn't hesitate when he revs it. Thank You for any suggestions.
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J.D. Green
#13 Charger Class - DIRT
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SS_99
Joined: 24 Mar 2009
Posts: 58
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| Posted: Tue Mar 31, 2009 12:51 am Post subject: |
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| we run a 500 cfm 2bbl as well but mine is the ketih dorton series holley and i have absolutley no hesitation in mine your hesitation is caused by one of a few things you either are getting to much air at one time for the amount of fuel its getting. Or your getting more fuel than air You may want to look at these things for the best performance check to see the size of the jets the squirter and if you have changeable air bleeds the size of them as far as the power vlave it will cause a hesitation if its not right as well we run 75 jets for cold weather a 4.5 power valve this depends on the intake and cubic ingh of the engine it delivers fuel by the vacum created by the intake also you will need to figure out what is stopping the squirters from squirting soon enough they should start squirting as quick as you touch the throttle. timing can also cause this problem our timing is generally at 34 advance |
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RW_Motorsports
Joined: 24 Mar 2009
Posts: 66
Location: Circleville
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| Posted: Tue Mar 31, 2009 10:32 am Post subject: |
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| SS_99 wrote: |
| we run a 500 cfm 2bbl as well but mine is the ketih dorton series holley and i have absolutley no hesitation in mine your hesitation is caused by one of a few things you either are getting to much air at one time for the amount of fuel its getting. Or your getting more fuel than air You may want to look at these things for the best performance check to see the size of the jets the squirter and if you have changeable air bleeds the size of them as far as the power vlave it will cause a hesitation if its not right as well we run 75 jets for cold weather a 4.5 power valve this depends on the intake and cubic ingh of the engine it delivers fuel by the vacum created by the intake also you will need to figure out what is stopping the squirters from squirting soon enough they should start squirting as quick as you touch the throttle. timing can also cause this problem our timing is generally at 34 advance |
SS_99 has you on the right track. We ran a 500cfm 4412 for a couple of years. I'm pretty sure we settled with 76 jets, a 30cc accelerator pump and 4.5 power valve. There def should be NO hesitation what so ever. If you are seeing a hesitation in the spray when picking up the throttle I would also check the following and in this order:
1) float level - should be set with enine idling so that fuel is just coming out the screw hole in the side of the fuel bowl. If you run a high bank track I would set it a little higher so maybe 1/4 of the hole.
2) accelerator pump diaphram - could be weak or worn out (they're cheap). Make sure the accelerator pump linkage is set so that the adjuster screw with the spring over it is touching the accelerator pump arm. Otherwise there will be hesitation in the action of the linkage.
3) fuel pump pressure.
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Dpassmore
Joined: 23 Mar 2009
Posts: 36
Location: Birmingham Al.
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| Posted: Fri Apr 03, 2009 1:55 pm Post subject: |
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The proper accelerator pump adjustment is to hold it the throttle wide open.Push the pump lever down with a screwdriver,and check clearance.It should be .0015 if I remember correct.
I'm not saying that's the problem.It does sound like for whatever reason it's going lean just off idle.
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