Re: 2 cycle outboard motor external fuel tanks require fuel pumps!

From: Eric Johnson (etj@nwlink.com)
Date: Mon Mar 20 2000 - 22:46:25 PST


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>Please don't get mad at me...

why would I?

>I have investigated this topic to exhaustion. If you go back in archives you

>will find me searching for a solution. The 3.5 Nissan manual actually shows

>the installation of a fuel pump to a hole in crankcase for an external tank

>option.

Must be the service manual, owner's manual doesn't say anything about it. And
I believe you :)

>However, no luck locating one from Nissan/Tohatsu or Merc.

Try mastertech at http://www.maxrules.com/ if you haven't already. I just ordered
a lower-pitch prop from him for my 5hp Tohatsu (only $58 delivered!) and he
seems to really know his stuff.

I asked a few other knowledgable people and it turns out some very old small
outboards actually did use no fuel pump, but since 1960 or so all external tanked
outboards indeed use fuel pumps. I've apparently just not noticed it :)

>I have several shop manuals for Evinrude, Nissan/Tohatsu, Merc for all
>outboards from 2hp thru 150. <snip>

Where did you hunt down a Tohatsu manual? I'd like to get one, but haven't had
any luck.

>You need a fuel pump. Don't none of you guys go out and get an external 3.5

>gallon fuel tank expecting to just hook it through fitting and run off of it.

Agreed. thats why i brought it up..i actually have one of these old motors (1952
Elgin) that doesn't use one, so thats what confused me.

>Only the Evinrude 4 has a fuel pump neither Nissan/tohatsu or Merc under 5

>have one.
>
>Heck! I even toyed with the idea of putting in an automotive electric fuel

>pump powered by onboard battery to run the lil 3.5 of an external tank. I

>chickened out with fear of fuel leakage or Boom! Blowing myself up. Another

>time I toyed with idea of mounting tank on coaming and hooking it up to top

>of gas cap so it would gravity feed. EcoTerrorist wife stopped me...

Have you thought of a lightly pressurized tank system? you could put a tire
valve stem on a gas tank, use a small portable bicycle pump to pressure the
tank to a few PSI - that ought to be reasonably safe, easy to fabricate and
use, and give at least as much pressure as the few inches of gravity feed. If
you want to get really fancy you could add a small pressure gauge so you don't
overdo it...
http://www.nwlink.com



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