Think I wrecked my carb

Since I had some spare time today I decided to take my carb apart so I could take away to get ultrasonic cleaned. Something I had planned for this winter since I was suspecting the carb for being the cause of some issues.

So I took it off and started to take it apart, but when I got to the jets, they wouldn't get out, at least 3 didn't. One came out pretty easy but the other three, pfff, no chance.

I tried everything, from the screw driver, when that one failed it tapped in a torx-bit but no result. After that a left handed drill bit, no result, so I went for my screw extractor set.

No result at all. Those things where so seized up, unbelievable. On 1 side the jet mount kind of broke loose, just a small fracture, something I probable can fix, but this also indicates how tight these things were.

After all this I ended up with a carb with 3 holes where I only can try to cut new thread for the jets, if I have enough metal left.

Any thoughts or should I consider this carb lost and should I start looking for a new 3665. Maybe a gift for my wife for this Christmas?

Kind of like locking the barn after the horse escapes; but ONE of the reasons for using the ultrasonic cleaner is to help the carb come apart. The ultrasonic waves would probably have allowed the jets to be removed.

The 3665s is relatively common as Buick carbs go here in the USA.

Yours IS repairable; but the cost would probably exceed the cost of just getting another unit.

Then you will have the current unit as a "parts" carb.

Jon.

Kind of like locking the barn after the horse escapes; but ONE of the reasons for using the ultrasonic cleaner is to help the carb come apart. The ultrasonic waves would probably have allowed the jets to be removed.

The 3665s is relatively common as Buick carbs go here in the USA.

Yours IS repairable; but the cost would probably exceed the cost of just getting another unit.

Then you will have the current unit as a "parts" carb.

Jon.

Hi Jon,

What is the procedure to make such a repair? Thanks,

Tom Mooney

Tom - one needs to have a good, disassembled body of the same carburetor as a pattern. Take all the necessary measurements from the good core. Take the body to a GOOD welder that can weld aluminum, and completely fill the hole(s) with aluminum. Now remachine the body. Don't forget to remove the access plugs to remachine the passages.

The tolerance on the primary is critical, because of the metering rods. The tolerance on the secondary is less critical, but still, any competant machinist would want to be as accurate as possible.

We have done this repair a number of times in the past on rare carbs when someone tried to remove a jet with a not-so-easy-out; which should NEVER be used on soft metals such as brass. With the 3665s, less expensive (at least today) to start with a different core.

Remember that the holes for the jets will have to be cut with an end mill and the jet thread will require finishing with a 'bottom' tap.

Most (not all) Carter jets are 5/16 x 24 thread. However, there are at least 3 different jet lengths.

Jon.

Tom - one needs to have a good, disassembled body of the same carburetor as a pattern. Take all the necessary measurements from the good core. Take the body to a GOOD welder that can weld aluminum, and completely fill the hole(s) with aluminum. Now remachine the body. Don't forget to remove the access plugs to remachine the passages.

The tolerance on the primary is critical, because of the metering rods. The tolerance on the secondary is less critical, but still, any competant machinist would want to be as accurate as possible.

We have done this repair a number of times in the past on rare carbs when someone tried to remove a jet with a not-so-easy-out; which should NEVER be used on soft metals such as brass. With the 3665s, less expensive (at least today) to start with a different core.

Remember that the holes for the jets will have to be cut with an end mill and the jet thread will require finishing with a 'bottom' tap.

Most (not all) Carter jets are 5/16 x 24 thread. However, there are at least 3 different jet lengths.

Jon.

Jon,

Thanks for the GREAT reply. When I asked about repair technique I overlooked the fact in this situation we are looking at a broken casting. My question was more like "how to remove a stubborn jet" before breaking the casting.

Your points regarding an end mill are well taken as the jet must bottom on a flange left in the casting at the bottom of the machined hole for the jet, correct? And because of this flange the threads must be cut down to this flange, correct?

So, after basically destroying the slot in the brass jet what is the best technique to proceed with a repair from that point? Thanks in ad!

Tom Mooneyce

Last weekend we used an end mill while putting a new hinge pin in my Packard door. Maybe I get too fussy about how to do stuff.

For future reference on the carb work, I have a 4 ounce ball peen hammer that keeps me out of a lot of trouble. Like the ultrasonic cleaner, I use it to lightly tap small parts or dissimilar metal parts to create a "ringing" vibration on screw head or hex head fasteners. A tight fit is important. Sometimes carburetor jets require a slightly thicker tool than a screw driver. I hold the hammer loosely in my hand and use a wrist action to keep tapping, and taping, and taping, sometimes until I am ready to give up. Then I tap some more. In most instances the fastener will loosen, take penetrating oil and successfully work out.

I learned this technique working on heating radiator steam traps in the early 1970's. The hex heads on the traps would be all scarred and torn up from 36" pipe wrenches when I got there. I would just sit on the floor with my little hammer tapping the perimeter of the body and eventually unscrew the cap with my fingers. It has worked very well on everything except Buick water pump bolts. I use magic for that.

So, on the next job, get a good fit (if it is an expensive carb tool use an expendable short extension to tap on) and tap like you are ringing a bell for as long as it takes; been working for me.

Bernie

Tom - PERFECT THIS ROUTINE ON JUNK CARBS BEFORE TRYING IT ON A CARB YOU WANT TO KEEP!!!!! DO NOT USE THIS PROCEDURE ON ZINC ALLOY CASTINGS (IE ROCHESTER 4 JET)!!

If the ultrasonic does not loosen the jet(s) (it does probably 99 percent of the time):

Remove the floats and any springs from the carburetor.

Assemble the following "tools":

A screwdriver with a edge that fits the jet perfectly

A five gallon bucket, with a 1 inch thick layer of foam rubber in the bottom

An ELECTRIC toaster oven

An acetylene torch

A pair of large Vise-Grips.

Procedure:

Fill the bucket appoximately 2/3 full with ordinary water

Place the casting in the toaster over, and get as hot as possible (probably about 450 degrees)

Using the Vise-Grips, remove the casting from the over

Fire up the torch, with a small tip and a 'pencil' flame

Play the blue of the pencil flame over the outside rim of the jet (STAY OF THE ALUMINUM!)

When the blue flame turns yellowish green, drop the casting in the water.

Do the above as many times as needed (generally once or twice will suffice).

A carburetor is a perfect example of a Galvanic Cell. The resulting ion flow builds up corrosion in the threads. The heat burns the oxygen from the corrosion molecules, thus reducing the volume.

Jon

Tom - PERFECT THIS ROUTINE ON JUNK CARBS BEFORE TRYING IT ON A CARB YOU WANT TO KEEP!!!!! DO NOT USE THIS PROCEDURE ON ZINC ALLOY CASTINGS (IE ROCHESTER 4 JET)!!

If the ultrasonic does not loosen the jet(s) (it does probably 99 percent of the time):

Remove the floats and any springs from the carburetor.

Assemble the following "tools":

A screwdriver with a edge that fits the jet perfectly

A five gallon bucket, with a 1 inch thick layer of foam rubber in the bottom

An ELECTRIC toaster oven

An acetylene torch

A pair of large Vise-Grips.

Procedure:

Fill the bucket appoximately 2/3 full with ordinary water

Place the casting in the toaster over, and get as hot as possible (probably about 450 degrees)

Using the Vise-Grips, remove the casting from the over

Fire up the torch, with a small tip and a 'pencil' flame

Play the blue of the pencil flame over the outside rim of the jet (STAY OF THE ALUMINUM!)

When the blue flame turns yellowish green, drop the casting in the water.

Do the above as many times as needed (generally once or twice will suffice).

A carburetor is a perfect example of a Galvanic Cell. The resulting ion flow builds up corrosion in the threads. The heat burns the oxygen from the corrosion molecules, thus reducing the volume.

Jon

Hi Jon,

Thanks again for the advice. Since the idea is heating and rapid cooling given differing expansion and contraction rates to break the bond between the casting and the jet, is it necessary to heat and cool the entire casting? Or can the same be accomplished by warming up the casting surrounding the jet, and mostly the jet itself, with the torch, and then quenching? Is heating and quenching the entire casting risking warping the casting? Thanks again,

Tom Mooney

Hmmm, when reading al this I realize I should of asked this sooner, would of have saved me a lot of money and frustration. Never realized that those brass jets could get so ridiculously stuck.

I’ve had my share of bolts and nuts that wouldn’t move but I always managed, one way or another, to get it out or loose,but these small brass things won.

Jon,I already emailed you through your companies website about a carb.

Tom - it may be possible to just heat the jet. The procedure I outlined is what I have been using for 40 years.

Marcel - I got your email, and have several used 3665s carbs. The problem for us is how to get one to you. We use UPS (United Parcel Service) for shipping, and their overseas rates are EXPENSIVE.

I have had so much bad luck with the post office that no way am I going to even attempt to use them.

Maybe someone else on these forums will have a 3665s.

Jon.

Thanks John, appreciate you sharing your experience,

Tom