My 65 350 HP car is up and running. Drove her over to the alignmant shop today. Done with that item. Now, after arriving home I tried again to adjust my Holley carburetor. Following my 65 manual. At running temp with a vacuum gauge teed into my vacuum advance. My driver side carb idle/mixture screw will not raise the vacuum reading. I have to start with the screw seated. Running the screw out only lowers the vacuum and the sound of the engine reflects that. The passenger side works great and is very responsive. IS this normal for these 40 year old Holleys? I thought I would ask the members here before calling my restore guy in NJ. Is my needle seat bad? There is a 1 year warranty on this carb. Anyone? Thanks for all your help doing this car. It is such a joy to drive. Finally after 4 years I can punch it and hang on. DG
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Re: Restored Holley problem
Further info. My highest vacuum reading is 13 lbs.. DG -
Re: Restored Holley problem
Dick...
Sometimes the mixture screw(s) will not adjust properly if the primary throttle plate is adjusted incorrectly...too far open.Comment
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Re: Restored Holley problem
The screw on the passenger side works great. Would that still imply the primary throttle plate is adjusted wrong? Thanks DGComment
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Re: Restored Holley problem
I'd contact the one who did the carb restoration. Often, the failure of these carbs to respond to idle mixture adjustment lies in the metering block being warped/worn such that the idle circuit is leaking fuel leaving one or both idle wells essentially dry.Comment
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Re: Restored Holley problem
Thanks for the reply. I will call them ASAP. I will see just how good their service is. Since we are the subject, what is an excellent direct fit replacement carburetor, 65 327/350. Thanks DGComment
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Try a new one
Dick: Thankfully, Holley has reintroduced the 2818. $595 on Ebay.Comment
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Re: Try a new one
I will check it out and see if that carburetor is available at all Holley dealers. Thanks DGComment
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Re: Restored Holley problem
Dick,
I'm more familiar with my 67 300 HP base engine with a Holley 3810, and that vacuum seems pretty low. I pull 17 at idle, but 13 may very well be normal for a 350 Hp engine.
Lack of adjustment of the mixture screws could be caused by low vacuum, vacuum leaks, and the secondary throttle plate being too far open. Vacuum could also be effected by initial timing; is the intial timing to spec?
Are you having problems with overheating at idle or high speed? If not, and you are happy with the power and have a reasonable (slighty higher than spec) idle speed, maybe not worry about the one side mixture screw, just make the adjustment the same on both sides.
I think the service manual mixture adjustment is to initally adjust the screws out 3 turns, then turn them in to a lean roll (20 to 30 rpm drop), then out a quarter turn. Try the adjustment a little at a time on both sides, maybe a half turn in at a time. When you hit the lean roll on one side, adjust that one out the 1/4 turn, then adjust the other the same way or to the same position.
On my 3810, the adjustment is about 1 turn out on both sides.
If you are overheating at high speeds, that is probably a vacuum leak in the base gasket or throttle shafts. I have found on a newly installed carb, that the problem sometimes goes away, if you let it overheat a couple of times and let the gasket take a set.
I'm not a mechanic or expert on this, I just like to tinker.
Having fun,
Jerry Fuccillo
#42179Jerry Fuccillo
1967 327/300 Convertible since 1968Comment
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Re:Update: Restored Holley problem
Thanks for the reply. This morning my engine builder stopped by. He also tried to adjust carb. Again, the driver side mixture screw only hurts vacuum when turning out from a seated position. He tried an old trick he has used before by revving up engine and quickly lay your hand over primary hoping this will pull out the obstruction. No luck. He also checked float level and adjusted the front. Ok, now he got out the gumout. When he attempted to spray gumout into the driver's side primary air bleeder gumout could not enter. So he tried the passenger side and immediately the engine began to bog down. This driver side air bleeder is blocked. He thinks we or my carb builder should jet this Holley down. Maybe when unplugged this carb. will run leaner? Any suggestions. When I removed carburetor I observed unburned fuel pooled in the intake grooves in throat of intake. Normal? I don't want to damage this engine with undo amounts of fuel. I have carburetor packed up and ready to ship out to my builder. I will see how good their service is. It is under warranty. Thanks DGComment
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Re:Update: Restored Holley problem
Dick,
I had a similar problem with blocked vents on a 3810 I restored. There are 4 vents in the air horn on each side. The larger ones are the idle vents and the smaller ones are the high speed vents. On this 3810 I acquired one HS vent on the primary and one on the secondary side was intentionally blocked.
All of these vents should be open to the metering blocks or plates (at least on a 3810). One should be able to blow compressed air from the metering block up through the air horn vents. I had to drill mine out in the air horn and also one in the metering plate. Clem gave me the correct drill sizes.
The purpose of the vents, as I understand, is to atomize the fuel into the air horn. If blocked, fuel will just drip in and you can getting siphoning of fuel into the air horn, making it over-rich. I think unblocking the vent, both in the airhorn and metering block, will lean out the mix and give you back your mixture adjustment.
Another problem I had with my carb was it was down-jetted from spec. (I think this carb was modified for use on a go-cart or 4 or 6 cylinder engine ) It had 62 jets whereas 65 are spec). The result was that it would get very hot at high speed and accelleration, going up a hill.
So if you re-jet it, go to original spec.
For a 2818-1 the jetting from my Holley book is:
Primary jets #65
Secondary jets #76
Power Valve (primary only) #65
Use an original type power valve (single stage)
I think you will solve your problems with opening up all of the vents, (have them all checked to the metering blocks), and jetting to original spec.
Having fun yet,
Jerry FuccilloJerry Fuccillo
1967 327/300 Convertible since 1968Comment
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Re:Update: Restored Holley problem
This is fun, but I'd rather be running through the gears. This car has only 50 miles on her. I have held up on shipping this carb back to the rebuilder for fear of missing what is left of the summer. There is a Holley man in town who is well respected. So warranrty or not I will give him a shot. I will try the compressed air. Thanks DGComment
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Re:Update: Restored Holley problem
Dick,
If you are going to get it done locally, here's a pic that might help:
This is a Holley 3810, with a 4743 metering block turned 180 to show the mating surface to the body.
The four holes horizontally across the top (-1/8") of the mating surface on the body, lead directly to the four vents in the air horn. They should blow free and clear.
The holes in the body correspond to the 4 tracks in the meter body. Check to see that all of the holes in the tracks are free and clear. The two outside vertical tracks are the idle vents and lead directly mixture screw.
If you have to drill any holes, in the vents or body, check the size with the butt end of a numbered drill on the corresponding good side, then drill it with a hand pinwheel. I actually had to drill one in the inner high speed track on mine.
Hope this helps.
Jerry FuccilloJerry Fuccillo
1967 327/300 Convertible since 1968Comment
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Re:Update: Restored Holley problem
Jerry Thanks for the help. At this time I cannot get a hold the local Holley (man). Should be interesting to see what he thinks. My engine builder thinks they (carb rebuilder) when they bead blasted the carb they accidently got a buildup of the media packed in tight inside the carb. Thanks DGComment
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Re:Update: Restored Holley problem
Dick,
Leaving glassbeads in the body passageways could hurt your engine. I would think that any restorer would make sure that all passageways were thoroughly cleaned out of any remnants of the glassbeading and plating process, and flow tested.
In fact, that's how I found that a few of my vents were never drilled. After beadblasting and plating the body, I went through it by blowing compressed air through all the passageways. I came across a few high speed vents in the air horn which were never drilled, and then took a closer look.
In the picture below:
in the track at the point of the awl is where I had to drill a hole in the metering block, as well as a corresponding hole in the brass vent cap.
You might take a close look with a magnifying glass at the vents in the air horn, or try to put the butt end of a drill bit down the vent opening.
If you disassemble, also do the secondary side.
You might be wise to do this locally rather then sending it back on warranty, you never know what you are going to get back after a few months.
Have you been able to talk to the restorer?
Jerry FuccilloJerry Fuccillo
1967 327/300 Convertible since 1968Comment
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