How do you seal a brass fitting screwed into a steel carburetor or sediment bowl?

[Jstpssng]

Do I just turn them in dry until they stop or ?
I just put a new sediment bowl and carb on my (gas) TO35 and ran new fuel lines. Tomorrow I need to move it back undercover and would like to just dump fuel into it and go.
Does brass seal onto steel, or whatever metal they are made of?
Thank you.

 

[Roadworthy]

Carburetors are usually made of "pot metal" (aluminum). When screwing in a brass fitting, if the sealing surface is flat, usually a fiber or copper washer is used to make the seal.

 

[4570Man]

They usually have a sealing washer on them.

 

[Jstpssng]

Thanks, I knew that something wasn't right. They must have fallen out of the package, so I will have to come up with something.

 

[RickB]

There are several different connection types. Straight thread will need a sealing washer or o ring. Flare or inverted flare seal without anything. Many inlet fittings are pipe thread and will require dole or thread tape.

 

[skipmarcy]

If it is pipe thread I would use Teflon tape. You have to apply it properly though. Always leave the first thread or two bare of tape so it won't string-off and get into the system. Be careful with pipe thread too that you don't overtighten and split the unit you are screwing into - the Teflon tape will make it easier/smoother to screw in and is easy to over do it.

 

[TractorGuy]

For a tapered pipe thread with gas or oil I put a dab of Aviation Permatex on the threads.

As has already been said, most carburetors will have a straight thread with a sealing washer or flare type fitting.

 

[Jstpssng]

Thanks for the advice, now I know what to do next time. The lines are both flared so I guess that I'm OK. It's been 3 weeks since I hooked it up and couldn't remember how I had done it.

It turns out that was the least of my worries. I left the house at 4 this AM, hoping to get down there and get the tractor inside before it started raining, allowing me to change out he water pump while listening to the rain on the shop roof. Even if the lines leaked a little I could fix that once I got it inside.
After shutting the petcock off I dumped about a gallon of gas into the tank and went inside to get the battery. When I came out the fuel was running through my new petcock/sediment bowl, through my nice shiny new copper fuel line theway that it's supposed to and out my nice new $173 carburetor onto the ground. I pulled a tarp over it, went down and visited with my mother for a while, and came home. 8 hours on the road for 10 minutes of work... but at least the tractor is covered, rather than setting out in the rain.