Holley NH leaks

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Model T Ford Forum: Forum 2013: Holley NH leaks
Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Saturday, January 12, 2013 - 05:00 pm:

Well I finally found out what was causing my carburetor to leak. It would drip whether or not the tank valve was turned off.

I took the carb apart and cleaned it up, and noticed it had the neoprene needle valve, so I thought maybe the new gas was causing a problem so I ordered the original type needle and seat and a set of gaskets. Today I took it apart and replaced the needle and seat and gaskets. Put the carb on the car and it still dripped.

The design of both Kingston and Holley were poor! What I found was the brass insert which holds the bowl to the carburetor was leaking. About 1/4 turn fixed the leak. I don't know why both those carbs had that type of fastener to the bowl. It would have cost a few cents more to have a solid bowl and screws to hold it to the body at the top of the bowl. Well anyway, what I found was that on the bench I thought the insert was tight and didn't want to strip the brass. But after the carb was mounted to the manifold, I had more leverage and it felt very loose. When I tightened it the leak stopped. So much for now. I hope that's all that was leaking.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Saturday, January 12, 2013 - 05:41 pm:

Well! I just checked it again and there was a small seepage. This time I used fast drying hard setting permatex. I will let it set overnight with the gas turned off. I sure hope I got everything inside set correctly so it doesn't need to come apart soon!
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Monday, January 14, 2013 - 12:02 am:

On a oil pan plug and carburetor bowl nut and similar, you can often stop a leak by wrapping the threads with string just before you tighten it up.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Monday, January 14, 2013 - 12:12 am:

by brass insert are you talking about the large nut that holds the bowl on?

somtimes the bowls are really pitted or the nut is messed up, which can be a problem.

none of mine have leaked from there, even a holley G that just has an aluminum washer as a gasket, dont ask me how....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Monday, January 14, 2013 - 10:11 pm:

Did you put the gasket on the bowl retainer nut/drain (depending on which one you have)? Have you checked the float level? Even the Zenith Model A carbs were held together with only one bolt.


Top of pagePrevious messageNext messageBottom of page Link to this message  By A. Gustaf Bryngelson on Tuesday, January 15, 2013 - 08:40 am:

I recall hearing a story about an engineer bringing a prototype carb to Ford, that had a number of screws holding it together. His comment that there was too many screws, redesign it! You have to remember that screws were not as cheap as they are now, and that they were a part that could be damaged or come loose. The simplicity of the Carbs used on the T are amazing.
Best
Gus


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Bohlen, Severn MD on Tuesday, January 15, 2013 - 10:29 am:

Gus,

The story is from the development of the Model A.
To get the HP that Henry wanted out of the motor (40HP) they needed to change from a Holly carb to a Zenith.
(Henry was good friends with John Holly and there was concern he would balk) The Zenith had something like 16 screws holding it together. Henry took one look and said "To many...get rid of the screws" They went back to Zenith and they redesigned with 2 screws. Henry looked and said "Still to many" That's why the carb had one center bolt holding it together.

Oh, and as everyone knows they got the Model A to produce 40 hp.....

Larry


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Tuesday, January 15, 2013 - 10:54 am:

That story among others can be read in Philip Van Dorren Stern's 1955 book "Tin Lizzie".
Still easy to find: http://www.amazon.com/Tin-Lizzie-Story-Fabulous-Model/dp/B0017QFGQE/ref=sr_1_2?i e=UTF8&qid=1358265178&sr=8-2&keywords=van+doren+stern+tin+lizzie


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Tuesday, January 15, 2013 - 11:26 am:

It still leaks. The bowl doesn't leak, but seems something inside. The gas comes out the air intake around the choke. I replaced the needle and seat and set the float level. Is there anything internal to a Holley which could cause a leak other than the needle and seat?

It doesn't leak enough to cause any problem with the way the engine runs, just when parked. When I run out of gas, I want to use some timesaver on the shut off valve so at least I can turn it off and it will not leak.

P.S. The zenith carburetor has one bolt, but it doesn't go through the bowl.
Norm
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Tuesday, January 15, 2013 - 11:37 am:

If the gas come out the air intake then the float is set too high. Try setting the float to shut off the gas sooner. The float setting in the book is a rule of thumb, some carbs will very.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Hatch on Tuesday, January 15, 2013 - 04:16 pm:

When you put the elbow in that the gas line hooks to did you use Teflon tape? I have seen carbs that the tape will come apart and make the needle leak. Use fuel lube. Dan


Top of pagePrevious messageNext messageBottom of page Link to this message  By R.V. Anderson on Tuesday, January 15, 2013 - 05:00 pm:

Sounds like a plugged bowl vent. Drill it out and you're good to go.


Top of pagePrevious messageNext messageBottom of page Link to this message  By R.V. Anderson on Tuesday, January 15, 2013 - 05:03 pm:

Sounds like a plugged bowl vent. Drill it out and you're good to go.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money - Braidwood, IL on Tuesday, January 15, 2013 - 06:04 pm:

The seat can leak where it attaches to the body. One more thing to check.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Tuesday, January 15, 2013 - 06:45 pm:

It can leak around the threads of the seat for the needle.I aint sure it is worth a hoot but the last time I had 1 apart I put some of the yellow teflon tape around the threads of the needle seat and the bowl bolt.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilbur Swearingin--Mt.Vernon,MO on Tuesday, January 15, 2013 - 08:12 pm:

Check your gas tank. Small bits of rust or junk from an old gas tank will keep the needle from seating and carb will eternally leak till tank gets cleaned. Been there.


Top of pagePrevious messageNext messageBottom of page Link to this message  By A. Gustaf Bryngelson on Tuesday, January 15, 2013 - 08:16 pm:

Hey Larry,
Thanks for the history lesson, yes that is the story I remembered hearing.
Best
Gus


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred L. Olenberger on Wednesday, January 16, 2013 - 04:33 pm:

I have an NH Holley carb and it appears that I can screw the bowl bolt in far enough to block the hole that goes thru the treaded part of the bolt. Wouldn't that block the flow of the gas? From just eyeballing it I am guessing the gas gets sucked straight up from the bottom of the bowl and then heads out to the intake manifold. Your thoughts?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred L. Olenberger on Wednesday, January 16, 2013 - 04:36 pm:

I wouldn't think that would block the flow of gas but I am wondering about the function of that hole.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, January 16, 2013 - 07:10 pm:

I believe that hole is for draining the carburetor bowl. It looks as if there is another hole for the gas into the spray nozzle.
Norm


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