Scott Atwater 1-25 Fuel line help needed

[huntleybill]

I am restoring this 1-25 and am having a hard time figuring out these fuel lines. Pictured is the way I found the configuration when I started on the motor. This setup makes no sense. The setup shows a connection for a external tank. (Black rubber fuel line Arrow C). Arrow A shows a tube going from the on-board fuel tank as a drain tube (arrow B). This is the ONLY fuel connection on the gas tank. How can that be a drain???? I have no other motor or any pictures to show how this is supposed to be so my question is: Was there an external fuel tank option on these motors or is that rubber fuel line (C) supposed to be going where the drain tube (A,B) is? Or is this supposed to be configured another way?

Anyone have pictures of how this is supposed to be?

Also, There was a plate mounted by the 2 drain tubes (B) that held the tubes in place. Seems I have lost that plate!! Anyone have one of these?
Your help is appreciated.
Thank you
Bill

[frankr]

I guess I neglected to include this. This is all I know

[huntleybill]

Thank you Frank. This is helpful but does not show all the connections. I’ll study these more after I print them out.

[huntleybill]

Does anyone have a picture of their 1-25 of how these lines are supposed to be?

[retiredoz]

You have the optional external tank setup, which I don’t have. I’d hook a tank to the black inlet line and let it rip, the on-board tank may be just decorative. As you noted, it’s not plumbed to be used. I have no idea what the fitting is on the inlet, if it’s the one used on the 1-30 you may be out of luck. I’ll peruse my literature for wise words on the fuel pump kit..

• This reply was modified 2 years, 10 months ago by retiredoz.

[huntleybill]

Thanks retiredoz but now I need to know how the black inlet mounts on the motor. Would you have a picture of the bracket(s) used for that option? The motor had nothing there as the black inlet hose was just hanging.

[retiredoz]

Looking at my naked 10-hp, I’d say you’d just have to fake it. The fuel pump kit is an afterthought, so there’s no provision from the factory to accommodate it. I have a ’53 10-hp Firestone that came with a fuel pump, but it has the later-style carrying handle lower pan where the inlet line is mounted. The picture of the kit just shows a clamp on the inlet hose, I guess one could clamp it to the outside of the lower cowl ? Now that you bring this up, I’m going to reconsider my plan to move the fuel pump off the Firestone lol

[huntleybill]

So your saying that the fuel pump setup is an aftermarket kit?
I thought this was a dual source fuel setup. Either use the onboard tank or the external tank. It never occurred to me that it is converted to an external tank only. That might explain why the onboard fuel tank just has a drain tube, although why put a drain tube on something that is no longer used?!?!?. That’s too deep for me to ponder!

Okee dokee, I will finish hooking it up. I hope this fuel pump works!

[Tom]

I had one of these a while ago, but unfortunately I can’t remember how it switched over. I’m pretty sure there was a permanent mount for the external tank fitting. What I do remember is that it all leaked when using the onboard tank. And the tank is steel and hard to keep from rusting. So I went with what you have… onboard tank is bypassed, inlet goes directly to the fuel pump.

The fuel pump diaphragm should probably be replaced. You can get sheets of diaphragm material and cut your own, or see who has a small piece on this board. These pumps are very dependable with a new diaphragm.

The carburetor drain will also need attention. I’ve never been able to fix one of those so it doesn’t leak, so I remove the pin, tap the hole, and block it with a screw. It’s 2021, we shouldn’t be dumping fuel to drain a carburetor.

Finally, check the condition of the “driveshaft”. Some of these have a metal strip that acts as a shock absorber. It twist, shortens in length, and disengages between the two hard shafts. Fittings on the hard shafts are often broken. I don’t know if the one piece driveshaft from a ’53 will fit, but if it does it would be a wise upgrade.

Tom

[retiredoz]

If I could find a way to post pictures here, I could show excerpts from the ’52 Accessories catalog showing the fuel pump kit, and interestingly enough, another kit showing a two-way valve setup, using the on-board tank for ‘trolling’, and the external tank for the long run home (allowing for two different fuel mixtures). My semi-educated guess is that since Scott put the fuel pump on the 16-hp starting in 1950, by 1952 the concept had been proved enough to retrofit the 7.5 and 10-hp motors to keep users from complaining about having to refill the damn tank all the time, and the 5-hp was a throw-in. It’s not intuitively obvious how to connect an external fitting to the clunky cowlings, but I’m sure there’s a way. The cowlings changed in ’53, and by then the fuel pump was standard on all but the 3.6…

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