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hp500 ideling high

Old 06-05-2011, 07:26 PM
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Default hp500 ideling high

HP500 is ideling around 1100 rpm. It idels fine when first started then after you run it, it wants to idel around 1100 rpm.
The carb was rebuilt last year. I installed a set of lightning headers this winter. The idel screw is backed all the way out. I can adjust idel mixture screw all the way in and helps a littel but then it hesitates when taking off.
I am thinking i need to bump the jets up a size or two? What do you think?
I also have a holley hp950 that was on a hp500 making 600hp
but i think it might be to big for stock motor.
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Old 06-05-2011, 09:33 PM
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I believe hp500 had 800cfm's carbs
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Old 06-05-2011, 10:15 PM
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Bumping up the jets has nothing to do with the idle rpms. You probably have a vacuum leak somewhere around the intake or base of the carb.

Spray some carb cleaner around the intake and carb base and if the rpms of the engine change briefly you have a leak
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Old 06-06-2011, 12:24 AM
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It is the stock 800 with electric choke. I will check for leaks. Also could it be the electric choke?
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Old 06-06-2011, 05:47 AM
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if the choke does not come off all the way, yes could cause the high idle, make sure choke butterfly all the way and blip the throttle, shoud return to base idle when warm...how about cable not adjusted right and holding it up ?
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Old 06-06-2011, 12:14 PM
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I blipin the throttle dosent work. I adjusted the cable to make sure it is closed all the way and no luck. Ive heard of the fast idle cam hanging up so i was thinkin bout taking the choke off.
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Old 06-06-2011, 04:19 PM
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Default Fixx

remove carb,flip it up side down and make sure all the throttle blades are seated correctly,you have to loosen the screws on the blades so they seat..
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Old 06-06-2011, 05:53 PM
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Also make sure when you have the carb upside down that the secondary throttle plate idle screw is not adjusted to hold the secondaries open too much.
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