I have a single barrel Holley "1904" carb with a pretty cool glass see-through fuel bowl. Ever since I got fuel through it it has been leaking through the gasket that goes between the fuel bowl and the carb. The gasket that came with the kit is a skimpy little paper thing.
At first, it leaked quite quickly--it would empty the fuel bowl in a natter of 2-3 hours. Now--after tightening it down more and more a bit at a time-- it takes about 1 1/2 days. But I have tightened it down as far as it will go(before it feels like I'm going to strip the holes--the carb is only cast aluminum[and is 50 years old]).
I got a DIY gasket material set from kragen that comes with 3 sheets of synthetic rubber-type-plastic. Each sheet has a little more rubber content than the last.
I have heard gas likes to break down rubber over time. And I am afraid to use the rubber/paper material with a gasket exposed to fuel.
What material should I use? A new kit for these puny little carbs is $27-35. If they were still 6 bucks, I'd just go get another and rebuild it again for the fun of it.....but I can't afford that anymore(for one stupid gasket).
I'm assuming the little paper gaskets--that came with the initial kit--have worked for people for the last 50 years.....so what the heck?
Hmmm...finally a question I feel qualified to answer. I have the same carburetor and had the same problem. The paper gasket that comes with the rebuild kit doesn't seal well. For a good seal, get some cork/rubber gasket material from your parts store. As I recall, the package said it was recommended for exposure to fuel. Use the paper gasket in the kit as a template to cut a new gasket from the cork. Tighten the 4 screws that hold the metal retainer on the glass bowl carefully and evenly (the manual suggests 1/4 turn increments). Do not tighten those screws too much or you can warp the casting (trust me on that one). I find it easier to do this with the carb off and the bowl face up, but I have done it in place too--you just have to make sure the gasket stays in place, especially under the float where it's hard to see. If you haven't done it already, you should download the manual for that carb from www.oldcarprojectmanual.com . It will tell you everything you need to know about your carb.
Are you sure the gasket was tucked inside the metal lip everywhere and making good contact? I've had to make 2 or 3 gaskets at times before stopping a leak. If so, check the flange where the glass bowl seats--it may not be flat anymore. I have a warped 1904 that my glass bowl will not seal on, but its own metal bowl will seal if I use the cork material. If it is warped, I don't know if there is anything you can do about it. Maybe someone else can say. The 1904's come up on EBAY sometimes...
So I tried a bunch of stuff.....none of it worked. So I made yet another cork gasket and thought that it'd at least hold up until I find a better fix.
Then I was advised by my dad to put a thin layer of grease on the gasket(the stuff that comes in tubes for grease zurks[sp?]), it's not quite as heavy as axle grease.....So I did. I installed it and unbelievable it didn't leak. I ran it till hot, it still didn't leak.
Watched it like a hawk for an hour, didn't leak.
Come back after dinner ~4 hours later.......leaks. DAMN. It is much slower than any leak so far....but it still leaks. What the heck am I supposed to do....? This is not supposed to leak, so it shalt not leak!!!
Those old Holleys did tend to be overtightened over the years, which could cause enough of a warp to cause a leak, bit not easily be seen. I have used the paper type of gasket with good luck (I like the Vellumoid brand), but here is what I suggest you do.
Remove the screws, clamps, and bowl. Clean the mounting face on the carburetor really good, so you see nothing but bare metal. Check this surface with a straight edge (a 6" steel scale works best) and a flashlight. If you see any light between the straight edge anf the mounting face, you have a warp. Also check the clamps to make sure they are not bent or deformed, and straighten them as needed.
For gasket material, if you have no warp, a paper material will work. Sometimes I have used a very thin coat of Permatex No. 3 on both sides of the gasket. If you have a slight warp, I like a composition type material such as an elastomer impregnated cork about 1/16" thick. I have found this at tractor dealers repair shops, and in some Holley 4 barrel metering block gasket kits. With this, I generally do not use any gasket sealer.
If you have a noticible warp (more than about 1/32"), one thing you night try is a cork or composition gasket no thicker than 3/32" thick and a material called Loctite Gasket Eliminator # 515. This is good stuff, but not cheap. Completely coat the gasket with this (use your fingers, it wipes off easily) and install it and the bowl. Tighten the screws properly, then wait at least 45 minutes. (The #515 is anerobic, I like to give it some time to cure.) Then you can put fuel to it to see if the leak is solved.
3414, I'm really glad you stepped in with which sealer to use and how to use it. The reason I didn't mention using any sealer is because a mechanic using supposedly fuel-impervious gasket sealer on my old carb that leaked slightly is the EXACT reason why I decided I needed to learn as much about how my truck works and fix what I can myself! I wound up broken down on the side of the road because the sealer degraded and gummed up my carb. When I tore the carb apart, the sealer was everywhere inside and a bear to completely remove from all the surfaces. I always suspected that it wasn't given enough time to set up before the fuel was pumped back into the system.; that, or the wrong sealer sealer was used in the first place. Either way, because of that bad experience, I was turned off to gasket sealer in contact with gasoline. But it's good to hear from someone who uses the proper sealer, intalls it properly and has success with it. Loctite 515...thanks, I learned something here and, hopefully it works for moROT.
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