stratplus

Anyone know were to get a longer 12-28 squirter screw for my 4150 double pumper? Can it really be this hard to find a damn screw?

The top 3 or 4 threads in the base of the carb are just gone. Not stripped, but missing. So I can't screw in the discharge nozzle.

Standard length discharge screw is a 12-28 3/4" oval. If I went to a 1 inch that would be more than enough to grab a few more threads.

I called Holley and he said I think you will have a hard time finding a screw that size. He wasn't kidding.

Holley sent me to BLP and said they where a good company. They have a repair kit for the issue and long term I might go that route. But for right now a longer screw would solve the problem, quickly.

http://blp.com/cart/index.php?main_p...roducts_id=954

I went to McMaster, Fastenal, Grainger, all the local hardware stores, but no luck.

20round

BLP is the only way your going to make it work.. just bite the bullit. i have done several of these with no issues using there stuff..good luck

stratplus

Well, I just watched BLP's video. I don't see me doing this anytime soon. Its beyond my pay grade

The 1" screw idea is looking way better now.

JohnZ

Yes, it can - that screw is a "special", made only by Holley for that specific purpose; you'd be better off buying a new main body than ever expecting to find a 1" version of that screw.

-sinner-

Buy a used carb/base or maybe Helicoil? Don't those screws have internal channels that would make a hardware store replacement worthless? Helicoil is easy, and used 4150/4160s are dirt cheap, especially if you don't need them to be complete or run . . .

20round

yup you are correct johnz.. its not hard to do the helicoil kit for those.. if i had a numbers carb i would be fixing it at all cost

PAmotorman

a longer screw will prevent the tapered needle check valve from moving and allowing the fuel to flow.

stratplus

Interesting John about a "special" screw. Kind of like making a computer with a "special" operating system.

I was originally going to do a heli coil. But due to the two little slots in the discharge hole that are used for fuel transfer I didn't think that a heli would work.

Am I right or wrong about the slots not working if a heli is used?

PAmotorman

holley sells a hollow squirter screw that would work part # 121-7 but I don't know where you will find a heli coil kit.

ptjsk

Check with Allstate Carburetor on the east coast.

I have found they have every part I have ever needed.

Give them a call at 631 234-8327.

Pat

TCracingCA

Don't know how this would happen tightening down the chosen squirter with a screw driver because the screw bottoms on the top of the squirter, so i would bet the threads came out with the screw based on it being together a long time and when taking it apart, corrosion or something was in play here because gas flows up thru there. I dont see heli-coiling being used here because you can't replicate the groove with that type of sprung threading style (you can't break the winding of the heli-coil because the entire thing will fail). Maybe a thread insert, where a groove can be cut or filed back in, but not a heli-coil styled one. For a $100 buck or so, I would just get a new main body.

stratplus

Pamotorman a 121-7 hollow screw does not buy me anything because I am only using .28 squirters and hollows are used for maybe .40 and above for more fuel. The 121-7's are the same length as the solid screws I am using.

ptjsk, I called Allstate and they will fix the body with an insert for $45 and a 3 day turnaround. My guess is that it is the same type of insert that BLP is using.

It looks like the Allstate is my best bet. I prefer to fix it myself, but in this case for $45 plus shipping this is my best bet.

TC, you are correct, no clue how this happened. I have replaced the squirters in the past changing from a .28 to a 32 as a performance test.

DansYellow66

This may be completely off-base (and not especially elegant) as I may not fully understand the issue - but would a piece of 12-28 all thread cut to length and a nut/washer on top to secure the squirter work for now?

TCracingCA

First no threads for threading anything (in the picture provided- what threads? I see none left, so this was a total failure)! Second, there are fuel washers and the screw has a cone type shape which is a sealing surface and possibly spacing for metered amounts. I bet someone probably wasn't using the top gasket/washer and the screw threads bit farther down. I would have to study the internal schematic as to the affect a slight depth change would have or whether just the washer left out, caused the bolt to bottom and thus continued tightening would result in jumping thread and skip- stripping it out. I don't think they are that precision fitted, even though some of the volume control would be the clearance at the bottom of the screw as evidenced by the notching and that kind of if I am thinking right, is the top stop of the check discharge valve. I do not have one in front of me! But the pump action, stop and go of fuel is a function that happens elsewhere with the throttle and the lower carb internals that send or don't send fuel to the top. The top where we are talking about is more physical sized control by orifice size volume and rate, instead of actuation. I will see if I can find a pump accelerator schematic and post also! I would also say that there could be an indexing of the screw maybe, as to thread depth and precision, but then maybe not! I would have to play with a few of my carbs to know for sure.

Maybe put a pic up so everyone can follow along!



So I bet I could improvise a number of temporary fixes on something like this using everything from epoxy to whatever, but I thought a permanent main body saving fix is what was being pursued.

Naturally the picture shows one of the fancier nozzle types, that allows just slightly less airflow disturbance? of the pump shot, but they look cool so I use these myself. But the screw is a fuel channeling device and sealing surface thing- all in one.

Here is the circuit, but I wasn't able to find a cross section drawing of the Accelerator nozzle screw depth in relation to the seating depth etc. into this cavity.



If I was home, I could run a screw down thru the accelerator pump nozzle without one or both washers/gaskets and see if it bottoms or fails to lock the accelerator pump nozzle unit. I bet without the washers and gaskets with the screw fully engaged, you could possibly still spin the nozzle or there is adequate clearance to lock the nozzle (gasket/washer less) maybe, but can't be for sure without having one in my hand.

I would guess also that the screw was tightened while the carb was hot or someone took the screw out while the carb was heated up, adding to the failure. On aluminum, I like things room temperature, but we have entire threads on this topic and I am trying to not start something for the extra time on their hands crowd!

PS many drag racers don't even run the discharge check valve on the top! But for the street, I would always run one, because when not pressurized by fuel delivery that lifts it from the tapered seat, it falls back down and gives a seal which helps prevent siphoning.

toddalin

I'm sitting here looking at a 32 squirter and screw from a 650 dp and there is no hole in the screw. It appears like the screw on the left, which is different to that on the right in the picture above.

The fuel just makes its way up around the threads and finds the two holes inside the squirter body. The thread is really an oddball size and I'm betting that someone stripped out your threads trying to use a screw with the wrong threads.

stratplus

My squirter screw is like the one pictured above on the left, solid no holes.

I am the only one to work on the carb since new and I have only used the screws provided with the carb and always used a top gasket, but not a gasket at the base of the squirter. I didn't realize until this week that each squirter has 2 gaskets. Have I taken the screw off and on when the carb is warm, probably.

Here is something of interest.

I just took the carb apart to send to Allstate. The same discharge hole that the threads are missing, the needle valve has kind of welded itself to the hole. I tried to pry it up, tap on it, use 90 lbs of air from the back of the hole on the bowl side that feeds the needle. Nothing, this needle is not moving. I have it soaking in a 50/50 mixture of acetone and auto trans fluid overnight. If that doesn't work I will try some heat.

toddalin

Then I guess maybe that at one time you "cross-threaded" it and must have really been bearing down. Something had to rip out the threads, and difference created by the gasket thickness doesn't seem like enough to do it.

VintageMusclecar

Quickest, easiest & most economical repair is to heli-coil the squirter boss and install a hollow squirter screw. I've done this repair more times than I can count and it works fine.

stratplus

I could not find a hollow screw for a .28 squirter. It appears the hollows are used for larger sizes. Total cost for the tools would be around $50. Cost wise, the 12/28 heli tools came to around $40 with shipping and a squirter, if I could find it would be another $10.

The cost of sending the body out with shipping is about $60

I ended sending the body out late yesterday. The other factor for me sending out the body to Allstate Carburetor was that for the life of me I could not get the needle valve out. Heat did not work. Tapping on it with a punch did not loosen it and the 50/50 acetone/auto trans fluid soak did not work. Because of the position of throttle body I could not get a drill in for an easy out.

I am sure there are others, but this gave me a good idea on costs.

http://www.blindrivetsupply.com/Reco...cs_p_2885.html

http://www.sri-supplies.com/recoil-t...621-34620.html

It makes me wonder. What was the frozen primary needle valve doing to the performance and operation of the carb. Any ideas on this?

TCracingCA

that we stop thinking about things. I have like 5 double pumpers in the garage and even though I have worked on them a ton of times, I couldn't tell you which accelerator screw I have in them. I see the slot on this OPs unit, so I would now assume solid screw style. Yes here is a guy that has done a bunch of them, and if you get the hollow bolt, then you could easily helicoil and you are done! If you were trying to fix it using the slot and the same style of screw, then no go with a helicoil. I am pretty sure the tune up kits have various nozzles and probably with those, the trick screws. I have bought a number of those Holley Trick kits, but off of my memory, I don't remember what is all in them without getting another! I have parts bin, so i have a bunch of drawers with everything in a double pumper plus!

I am now curious as to whether any of mine still have the solid screws! I am also curious as to why people are stripping these out?
For the stuck discharge valve! I assume if it was driving, you were getting fuel if it was off of the seat stuck, but you weren't getting any pump shot at all, if it has corroded itself to the seat. I like kerosene for soaking things and even though they stopped selling it in my State, i have carb chem-dip!