Fuel Line Question

Re-building a PCM-351W engine for a Fish Nautique. Have made upgrades with GT-40 Heads and a Performer Intake. Question for those who have made these changes - what fuel line did you use from the mechanical fuel pump to the carburetor inlet to accommodate the overall change in intake height? Really only interested in USCG approved options. Thanks in advance!

Try to make the hard line work. If not, I have a soft USCGA option for you.

When I get back to Florida that's second on my list, it's 3/8 brake line you need and a 1/4 x 3/8 90 for the pump part # 6432T128 at Mc Master Care. A tube bender and flare tool is needed also. Or go with what Zach has if you don't have all the tools

That fitting may take a 5/8" wrench Zach, but I suspect that's not it's nominal size. More likely to be 3/8" just like the line. Kind of a moot point, as the line will come with both fittings you need.

Fuel pumps do not all use the same npt threads. My older ones are smaller (maybe 1/4" like yours Gary) but the newer ones are larger. Either way, he won't need a 90 adapter if he already has an original hard fuel line plumbed.

I believe many auto parts stores will rent you the double flare tool for free. Possibly the bender as well, though they're not expensive to buy. Double flare tool is a little pricey though.

To clarify, the inverted flare nut for 3/8" OD tubing is threaded with 5/8"-18 threads. Zach is correct but just didn't explain it very well!

Well I'll be darned. I don't know my inverted flare fittings by heart (obviously)... I thought about the only thing you could count on in any thread size convention is that the nominal size rarely matches the dimensional size, and it never matches the wrench size. Guess there's an exception!

Still extraneous info he doesn't need ;)

3/8 brake line will come with the proper fittings for a semi-modern Holley marine carb, hence the recommendation to use that. Smaller brake lines would be sufficient (conquerer used something smaller like 7/16" on their engines) but the fitting size wouldn't line up.

TRBenj wrote: 3/8 brake line will come with the proper fittings for a semi-modern Holley marine carb, hence the recommendation to use that. Smaller brake lines would be sufficient (conquerer used something smaller like 7/16" on their engines) but the fitting size wouldn't line up.

I just carried the extra Holley inlet I have to the store to match up and then looked at one of my pumps,didn't know there was more than one pump size,I hope the one down south is the same! It would be so much easier if we could use AN hose and fittings like I did here,but I have heard from the neighbors that the coast guard does check so I don't want to gamble.

Naw Mark now that we have a newer boat Chris doesn't mind being seen with me so I use his

baitkiller wrote: You guys dont have a flare tool? Damn... I use mine at least once a decade. Indispensable.

John,
Keep in mind the fuel lines are double flared.