Holley Dissection Inspection...

[Doppleganger]

I started humming that conjunction junction whats your function with the title....that should date me.


Anyways.....ok, in cahoots with my incessant whining about these Holley carbs, here are the pics of it apart. You fellas have forgotten more about these things than I will ever know.....does anything jump out at you as to what needs done? Hopefully the blister pack stores carry the gaskets and such. My buddy is coming over tomorrow to help me figure this out.

fwiw.....I changed the rubber fuel lines and fuel pump out. Also found that there is no filter (originally was the small insert in the Q-Jet). Going to put an inline one in tomorrow.

Thanks in advance.

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[CoggedBelt75]

Looking at the pics, I would be concerned with all the crud around the bottom of the metering plate. Especially the build up at the right corner. If that got into the plate passages could be plugged inside. Even the discoloration on the front metering block leads me to think it needs a good soaking in a chemical bath. Use to be able to get a small tub at the parts store that did a great job of cleaning all the gunk out. Hope y’all figure it out.

 

[Rickf]

Looks like it was sitting for a long time with some type of liquid in the bowls. Gunk has a one gallon container of carb cleaner with a dunking basket. Get an official Holley carb rebuilding kit and follow the instructions.

 

[Doppleganger]

Yeah....the more I see of this thing the more I think the source's storyline of where he got it and how long ago starts to stink up the joint. I cant get a straight story out of anyone that has touched this truck or its parts.

I've used Berryman's (3/4 gallon can) for decarbonizing pistons....they come out looking new. Stuff is nasty to be around but does what it says. I thought about that but wondered about the plastic floats and such....they dont look easy to come out. Wondered what the harsh stuff would do to that.

Thanks a bunch fellas.

 

[bucket]

Looking at the pics, I would be concerned with all the crud around the bottom of the metering plate. Especially the build up at the right corner. If that got into the plate passages could be plugged inside. Even the discoloration on the front metering block leads me to think it needs a good soaking in a chemical bath. Use to be able to get a small tub at the parts store that did a great job of cleaning all the gunk out. Hope y’all figure it out.

Looks like it was sitting for a long time with some type of liquid in the bowls. Gunk has a one gallon container of carb cleaner with a dunking basket. Get an official Holley carb rebuilding kit and follow the instructions.

I agree with these fine folks. I'll also add that it might have had the cheap clear sight windows installed while it sat. They will deteriorate and/or melt over time and can leave a similar crud in the bowls.

 

[Doppleganger]

On that last pic, do those 6 screws need to come out to get the gasket off? That gasket is so disintegrated it isn't coming off intact like the others - so I cant tell if its pinched or not. If so, looks like I have to find one of those proprietary screwdrivers for it.

Also - how do you know if the power valve is blown? I have heard that a backfire can take them out too.

Can these be soaked without damaging the plastic floats and such?

Thanks again!

 

[1985c20]

Most of the carb cleaners say to remove any plastic or nylon pieces before soaking them. You’re going to want to take the carb completely apart remove all gaskets etc. The floats aren’t that hard to take off. Remove the e clip on the pivot stud and the float just slides off. You should take it off to check the needle and seat anyway. Didn’t you have trouble with no gas in one bowl?

 

[Doppleganger]

Didn’t you have trouble with no gas in one bowl?

I did with the rear - took the whole adjustment screw out and cleaned the needle - then it filled just fine. I also noticed that the thin rubber gaskets on the adjustment screws are about done. Hopefully all this stuff is in a kit or available locally.

 

[bucket]

Most O'Reilly stores carry a bunch of Holley stuff. They often have rebuild kits that cover most models too.

 

[Backfoot100]

Sorry for the delay answering this.

Agree with others here. That carb is in dire need of a cleaning and rebuild. You'll need a clutch head screwdriver to get that metering block off to clean and put new gaskets on.
You can get a cheap set from about any parts store or a bigger screwdriver bit kit may have them.
Make sure you get a genuine Holley rebuild kit. Anything else can be questionable quality.

 

[asltrfl]

Take her completely apart! Holley is actually very simple to rebuild, you need to get that metering plate off to see how bad it is behind it. Sometimes even regular screwdrivers will work in the "clutch" screws. A rebuild kit will come with a new power valve, but you can blow on the old one with your mouth to check for bad. Look at a few YouTube videos first, well worth your time, Holleys are very simple and easy once you get the hang of them. There are simple but hard to understand adjustment techniques, that takes experience, but you will get it from youtube and forums.

Float level must be right on, sounds like you figured that out way back. Accel pump must be right on. But before that all holes and orifices must be blown out with carb cleaner, run thin gauge wire through as many holes and orifices and jets as possible. Blow through holes with compressed air. You will find dozens of little holes everywhere that need to be cleaned, blown out, or carb cleanered before you pot it together. Most holes that get sprayed, should have spray come out somewhere else. There are a couple that dont. Again, youtube is your friend.

 

[Doppleganger]

Completely disassembled it and soaked it in Berryman's for about 30 min - came out looking like a new bumper. It had been sitting a long time. When I pulled the power valve it looked like green-yellow clay was built up around it. Reminded me of the heating elements in our water heater back home with hard water. After the soaking I used about 2 cans of carb cleaner in all the smaller orifices - still got some sand out. The smaller plate (think its a metering plate for the secondary? - last pic above) screws were so loose I could almost push them with my fingertips and twist to get them out - ?! Replaced everything. Those kits are pretty thorough. I also replaced the fuel pump (for the heck of it - looked replaced but who knows where the PO got it), ran a new more direct fuel line and added an easily seen clear filter. Have plenty of fuel flow.

Truck started right up and runs great. On a couple of trial runs, if you get on it now, 1/3 of the time it takes off. 2/3 of the time there is a hesitation and the slightest pop / backfire - but you could ease into it and drive it if you HAD to with no hesitation. I think I need to go back and check the timing again. My timing light is an OLD Sears/Sun gun.....has shorting issues so my buddy is coming over today with his Snap On so we can get it dialed it.

But its getting there! Thanks fellas for all the help / input. Couldn't do it without you.

 

[1985c20]

The having to ease into it sounds like you need a bigger accelerator pump shot. But its always good to check and set timing.

 

[Doppleganger]

The having to ease into it sounds like you need a bigger accelerator pump shot. But its always good to check and set timing.

Yep - thats another setting I dont think is 100% right either.

 

[Rickf]

When in doubt, see how the manufacturer does it.

https://www.holley.com/blog/post/carb_class_5_basic_carb_tuning_tips/