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View Full Version : Thread tape on fuel pump NPT fitting?


hkallestad
04-12-2010, 03:11 AM
Do you use thread tape on the NPT fittings on the fuel pump(351 Indmar)? The reason why I ask is the concern about getting thread tape pieces in to the fuel system.

CantRepeat
04-12-2010, 06:12 AM
If it's NPT then either plumbers tape or they make an NPT paste that you can use that is good too. I used it on the fitting for a fuel pressure gauge.

Permatex #80631

hkallestad
04-12-2010, 09:53 AM
I think I'll go with the locktite NPT paste.

CantRepeat
04-12-2010, 10:11 AM
I don't recall off and but aren't the fuel lines at the fuel pump flared? If so it shouldn't really need a thread sealer.

Jorski
04-12-2010, 12:15 PM
Never used either, and it has never leaked.

east tx skier
04-12-2010, 02:57 PM
I just replaced an antisiphon valve on my boat's fuel line. My marine mechanic recommended the paste over the tape for the concern over getting the tape in the fuel system. That's what I used and it has worked well.

hkallestad
04-12-2010, 03:12 PM
I don't recall off and but aren't the fuel lines at the fuel pump flared? If so it shouldn't really need a thread sealer.

The line itself is most often flared, but the ports at the pump itself is 1/4" NPT, so a 90 deg 1/4" NPT to 3/8" inverted flare fitting is most often used. I'm not going to use a flared pipe this time, I'm going for steel braided hose and AN-fittings and hose ends(used in automobile racing etc)

CantRepeat
04-12-2010, 04:12 PM
The line itself is most often flared, but the ports at the pump itself is 1/4" NPT, so a 90 deg 1/4" NPT to 3/8" inverted flare fitting is most often used. I'm not going to use a flared pipe this time, I'm going for steel braided hose and AN-fittings and hose ends(used in automobile racing etc)

Ah, I see. So then the paste is way to go.

Good luck on the project.

Chicago190
04-12-2010, 05:50 PM
I just replaced an antisiphon valve on my boat's fuel line. My marine mechanic recommended the paste over the tape for the concern over getting the tape in the fuel system. That's what I used and it has worked well.

This is the general rule when it comes to teflon tape and fuel systems. I remember someone told me that the normal teflon tape dissolves in gasoline, but I did a few searches on the internet and the results were inconclusive. They do make a different type of teflon tape that is designed for natural gas connections, it comes on a yellow roll and is available at most places like Home Depot or Lowes.

When I used to do fuel system work on cars, I always used Loctite PST thread sealant. Supposedly, it's the best stuff for sealing threads, but it is more expensive than teflon tape. http://www.hrpworld.com/index.cfm?form_prod_id=2073&action=product