NEED CARB HELP!

289 - 351 cid Small Block Performance
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62Cometman
Posts: 80
Joined: Tue Oct 03, 2017 3:47 pm

NEED CARB HELP!

Post by 62Cometman »

Alright folks, im pulling my hair out over here, i got everything put together on my comet after the v8 swap and got the car to roar to life, but it wants to idle reallllll high about 3000-3200 rpm, the engine is a blueprint motor and it came with a 600cfm holley 4160 mounted to it when i purchased the engine and unboxed it. I have tried every adjustment i can think of without avail. Ive adjusted the curb idle screw all the way out to where its not touching anything, ive adjusted the cam and fast idle screw out, ive adjusted the fuel mixture screw, ive double checked the timing, i made sure the butterflies were not being held open, i manually opened the choke all the way, nothing seems to be working and the car gets hot quickly as you can imagine with it idling that high, im waiting for the engine to cool down some before trying the propane gas trick to try and look for a vacuum leak as that is the only conclusion i can think of at this point. Ive run out of other ideas as to whats causing it to run that way any help or ideas would be greatly appreciated.
62 Comet 170, dagneham trans, 2.8 7.25 rear 260 T5 8 inch swap planned for the future.

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tomb22
Posts: 559
Joined: Thu Jan 28, 2016 7:11 pm

Re: NEED CARB HELP!

Post by tomb22 »

I just installed a new Holley on my car and had the same problem. I had to turn out the cold fast idle screw a long ways to get it to idle down. I read an article that said that's how Holley sends them out :roll: If you have it turned way out and still have the problem I would check the bowl floats and see if there adjusted correctly and that the needle and seats are working.
Hope this helps
tom
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tomb's 65

EarlyCometExposure
Posts: 7
Joined: Sat Apr 04, 2020 10:16 pm

Re: NEED CARB HELP!

Post by EarlyCometExposure »

62Cometman - I feel your pain.
I'm working on my '85 Mustang with the Holley/Motorcraft 4180C.
Every time I pull the carb off and check or clean something and test it again, it acts different.

When you say it was getting hot, as in normal engine temps or hotter than normal?


Searching the internet I just found this link:
(I believe it also covers the 4160)

http://www.garysgaragemahal.com/holley-4180c.html

62Cometman
Posts: 80
Joined: Tue Oct 03, 2017 3:47 pm

Re: NEED CARB HELP!

Post by 62Cometman »

Well according to the aftermarket gauge I had mounted under the dash it was reading 240 degrees after a few minutes, but thinking something was off, I used an infrared thermometer to test my theory and I was infact only running 180 degree and much have an air pocket around that sensor :roll: also i did find the source of the confirmed vacuum leak, I plugged the line from the PCV to the back of the carb base and voila the rpm dropped down to almost perfect and I was able to adjust them like normal, now I don't know if the pcv was junk or why there was such a vacuum leak there but its good for now, and I might just run another breather in that valve cover hole and keep the port block off in the carb for now. Hopefully, I did finally get to drive the car around the block and down the street some and it drive nice still has a chatter at take off but im almost 100% positive that is being cause by running too high a rear gear. but it really like 3rd and 4th at speed now. There a new vibration in the steering wheel which I think is the exhaust manifold hitting the gear box but ill have to fix that later or give up and go with the dougs tri Ys
62 Comet 170, dagneham trans, 2.8 7.25 rear 260 T5 8 inch swap planned for the future.

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