Sticky Throttle Plates
05-02-2011, 07:38 AM
#1
Sticky Throttle Plates I bought a Holley 750 DP new about three years back. When it gets hot the primary blades stick causing it to idle fast. I have to do a quick blip of the gas pedal to get it to set back down.
The problem is definitely not the linkage, there is actually slack in the cable. I have the double return springs that came with the Lokar throttle cable on it. When hot I can manually rev it up then slowly let off the throttle and it will stick. I don't have to push hard to get it to shut all the way. It just feels like something is sticking.
When I first got the carb I emailed Holley tech support and they told me to recenter the blades in the bores and retighten them. That actually worked for awhile, but now it is bad again. I remember trying a little WD40 on the throttle shafts, I'm wondering if that is what helped and not adjusting the blades.
Any suggestions? Think I can pull the shafts out and clean them up with out risking a vac leak? Add a third return spring? Time to buy a Quick Fuel billet baseplate?
The problem is definitely not the linkage, there is actually slack in the cable. I have the double return springs that came with the Lokar throttle cable on it. When hot I can manually rev it up then slowly let off the throttle and it will stick. I don't have to push hard to get it to shut all the way. It just feels like something is sticking.
When I first got the carb I emailed Holley tech support and they told me to recenter the blades in the bores and retighten them. That actually worked for awhile, but now it is bad again. I remember trying a little WD40 on the throttle shafts, I'm wondering if that is what helped and not adjusting the blades.
Any suggestions? Think I can pull the shafts out and clean them up with out risking a vac leak? Add a third return spring? Time to buy a Quick Fuel billet baseplate?
05-02-2011, 11:32 AM
#2
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You should be able to pull the screws out of the blades and pull the shafts and clean everything. Just check the shaft and bushings for slop or wear when you go to put it back together. Hope this helps, Eric L
05-02-2011, 11:52 AM
#3
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I bought a Holley 750 DP new about three years back. When it gets hot the primary blades stick causing it to idle fast. I have to do a quick blip of the gas pedal to get it to set back down.
The problem is definitely not the linkage, there is actually slack in the cable. I have the double return springs that came with the Lokar throttle cable on it. When hot I can manually rev it up then slowly let off the throttle and it will stick. I don't have to push hard to get it to shut all the way. It just feels like something is sticking.
When I first got the carb I emailed Holley tech support and they told me to recenter the blades in the bores and retighten them. That actually worked for awhile, but now it is bad again. I remember trying a little WD40 on the throttle shafts, I'm wondering if that is what helped and not adjusting the blades.
Any suggestions? Think I can pull the shafts out and clean them up with out risking a vac leak? Add a third return spring? Time to buy a Quick Fuel billet baseplate?
The problem is definitely not the linkage, there is actually slack in the cable. I have the double return springs that came with the Lokar throttle cable on it. When hot I can manually rev it up then slowly let off the throttle and it will stick. I don't have to push hard to get it to shut all the way. It just feels like something is sticking.
When I first got the carb I emailed Holley tech support and they told me to recenter the blades in the bores and retighten them. That actually worked for awhile, but now it is bad again. I remember trying a little WD40 on the throttle shafts, I'm wondering if that is what helped and not adjusting the blades.
Any suggestions? Think I can pull the shafts out and clean them up with out risking a vac leak? Add a third return spring? Time to buy a Quick Fuel billet baseplate?
Ron
05-02-2011, 09:20 PM
#4
I bought a Holley 750 DP new about three years back. When it gets hot the primary blades stick causing it to idle fast. I have to do a quick blip of the gas pedal to get it to set back down.
The problem is definitely not the linkage, there is actually slack in the cable. I have the double return springs that came with the Lokar throttle cable on it. When hot I can manually rev it up then slowly let off the throttle and it will stick. I don't have to push hard to get it to shut all the way. It just feels like something is sticking.
When I first got the carb I emailed Holley tech support and they told me to recenter the blades in the bores and retighten them. That actually worked for awhile, but now it is bad again. I remember trying a little WD40 on the throttle shafts, I'm wondering if that is what helped and not adjusting the blades.
Any suggestions? Think I can pull the shafts out and clean them up with out risking a vac leak? Add a third return spring? Time to buy a Quick Fuel billet baseplate?
The problem is definitely not the linkage, there is actually slack in the cable. I have the double return springs that came with the Lokar throttle cable on it. When hot I can manually rev it up then slowly let off the throttle and it will stick. I don't have to push hard to get it to shut all the way. It just feels like something is sticking.
When I first got the carb I emailed Holley tech support and they told me to recenter the blades in the bores and retighten them. That actually worked for awhile, but now it is bad again. I remember trying a little WD40 on the throttle shafts, I'm wondering if that is what helped and not adjusting the blades.
Any suggestions? Think I can pull the shafts out and clean them up with out risking a vac leak? Add a third return spring? Time to buy a Quick Fuel billet baseplate?
05-03-2011, 08:27 AM
#5
Well I'm getting tired of living with it. Not good hearing this is a common problem, maybe I will bother Holley again.
I actually looked for a donor carb at a swap meet this weekend, but some of those old Holleys looked in pretty bad shape. The quick fuel/proform stuff look nice. They have secondary idle screws accessible from above, low profile throttle plates and teflon throttle shaft bushings. Just pricey.
think I will try tuning up what I have first and go from there. Maybe I will get lucky and find a casting burr or something.
I actually looked for a donor carb at a swap meet this weekend, but some of those old Holleys looked in pretty bad shape. The quick fuel/proform stuff look nice. They have secondary idle screws accessible from above, low profile throttle plates and teflon throttle shaft bushings. Just pricey.
think I will try tuning up what I have first and go from there. Maybe I will get lucky and find a casting burr or something.
05-11-2011, 07:24 PM
#6
Might have fixed the problem. Need to put a few miles on it to be sure.
Took everything apart and clean up the throttle shafts. Found a burr inside one of the base plate bores and some sharp corners at the edge of each bore. Cleaned and smoothed out the bores with a wood dowel (fit perfectly). Radiused the edge of the bore with emery paper. Then took #00 steel wool the clean up the shafts.
Put everything together making sure to complete close the plates and centering the throttle plates when tightening the screws.
I also put a little distributor grease on the shafts. Not sure if that was a good idea or not. Will let you know how things hold up.
Took everything apart and clean up the throttle shafts. Found a burr inside one of the base plate bores and some sharp corners at the edge of each bore. Cleaned and smoothed out the bores with a wood dowel (fit perfectly). Radiused the edge of the bore with emery paper. Then took #00 steel wool the clean up the shafts.
Put everything together making sure to complete close the plates and centering the throttle plates when tightening the screws.
I also put a little distributor grease on the shafts. Not sure if that was a good idea or not. Will let you know how things hold up.
