hp 500 carb leaking
 

hp 500 wont idle. too rich found fuel dribbling out of secondaries. needle and seat? saturated float? any ideas

Have you tried adjusting the needle seat/float level????

Fixx
 

what griff said,try removing the needle and seat,it will unscrew from the top..their may be a piece of crud in it,,look closely and if not replace both of them(front and rear)

can the float levels get out of adjustment for no reason? ALSO TO ADJUST THEM DO YOU LET IT RUN AT IDLE AND SET IT JUST COME OUT OF THE WEEP HOLE?

I was gonna say it could be a blown powervalve, but i am pretty sure the 500HP carbs didnt use a rear powervalve.

I am going with some crud in the needle and seat assembly!

Fixx
 

no! unless they were real high to begin with and unless you hit some major waves all the time then mabe..pull the needles,just unscrew them with a wrench not a screwdriver,this way you wont loose the adjustment..

yes pull the wheep hole plug and start the engine, WARNING!! if theirs somthing stuck in the needle and seat it will poar fuel out of the wheep hole so pull the needle and seat first and check it for crud..

ok ill try that thanks guys

I am having the same problem with my HP500's. bdr67, let me know how it goes.

Does anyone know what the model of the Holley carbs are on the HP500's? is it the 4500 by any chance....... http://www.holley.com/data/TechServi...ded%20View.pdf

The HP 500 carbs are Holley 4150's --800cfm, model 9022.
No rear powervalve in them.

ok had a couple of minutes last night to pull the rear needle and seat. could not find any debris in it. also shook the boat and could look down the hole and see the float moving up and down. so im figuring the float is working correctly. should i start the boat and adjust the level? should i replace the needle and seat and then adjust it? never had time to start it last night.

Fixx
 

you can try to adjust it and see what happens..the newer fuels with the alchol in it may be doing a number on the tip of the needle..if it were me i would replace the front and the rear needle and seat's..

mr fixall are the numbers stamped on the needle valevsso i can match them up?

Pretty sure it will be a standard Holley needle and seat, that come in a "trick" kit, or rebuild kit. Most autozone, pep boys, advance, etc, stock the holley kits.

Fixx
 

go with holley # 6-518-2

called holley and gave them the number off my carb they said use a 6-504. does that sound right? thanks.

replaced rear needle and seat and adjust now it idles great again. also replaced fwd one as precautionary. runing good again thanks for the help guys.

Fixx
 

their is a 10cc difference in fuel rate between the 2 numbers,,the # Holley gave you is a 110 cc needle and seat and the one i gave you is 120cc,,all it does is fill the fuel bowls of the carb faster..


Glad it all worked out :)

Technically you would need to lower the float level to run the larger needle/seat. More area of needle exposed to the same fuel pump pressure. You need to sink the float a bit deeper to balance the increase force on the needle. Otherwise you can end up having the same issue he started with.

Just a little FYI............