F-12 fuel pipe vent

[Chris NW Ind]

Can anybody tell what, if anything, is meant to screw into the top of this part? It came to me with this brass valve. I operate the tractor with the valve open. But, the valve doesn't seem to be original and I can't tell what should be there. Can someone help with info? Thanks, Chris B.

 

[rustred]

never saw such a set up, is that the top of the tank.? nice to see a bigger picture with more tractor to see what actually you got going on there.

 

[Chris NW Ind]

It's dark out now so I can't get a picture, but this is the image in the manual including the piping and vent. It is a Kerosene/distillate feature.

 

[Chris NW Ind]

Far as I understand, the vent is hollow and is simply a chamber higher than the carb and tank to feed fuel to the carb. I know the gas only motors have a tee at the top of the tank and eliminate some of that extra piping.

I just hoping to learn what closes the top of the vent. Can't just be a 1/8" npt hole open to the elements.

Thanks, Chris.

 

[rustred]

now i see ,... it appears to be a bleed off, it should be shut. the w-12's had that return to tank. i don't know what that is all about with that pet cock, probably a fuel pump primer. that petcock dont belong there.

 

[rustred]

just thinking,.. it might be to fill the carb with gas for starting as you wont start it on distillate.

 

[Chris NW Ind]

Thanks. It has become apparent the petcock doesn't belong. I just wanted to figure what belonged in its place.

 

[Chris NW Ind]

just thinking,.. it might be to fill the carb with gas for starting as you wont start it on distillate.

My manuals make no reference whatsoever to this vent or it's exact use.

 

[rustred]

well you know a fuel pump produces pressure, and on the w-12's the excess fuel was diverted to tank at the top. it might be a cushion for the fuel.

 

[Chris NW Ind]

Right. That's the gasoline only setup. This one uses the vent thingy as part of the kerosene setup. Different tanks, different piping. I don’t have the tank with the top return.

I have it starting and running pretty sweet and the petcock open or closed seems to make no difference. I'll just find a low profile brass plug and replace it.

 

[rustred]

That might cause an air lock. The carb bowl will fill before that canister. That is most likely why he had that petcock on it. That fuel pump will put out way more than that engine can burn. That is why the excess went back to tank. I heard you could run that engine for an hr. On one quart of gas.

 

[Chris NW Ind]

That might cause an air lock. The carb bowl will fill before that canister. That is most likely why he had that petcock on it. That fuel pump will put out way more than that engine can burn. That is why the excess went back to tank. I heard you could run that engine for an hr. On one quart of gas.

That brings me back to my original question: what belongs at the top of the vent if not a petcock and not a plug? Doesn't make sense to be wide open to atmosphere constantly. A picture would be worth a thousand words. Getting rid of the vent entirely isn't in the cards.

 

[Chris NW Ind]

Scanned my parts list again and this appears to be what caps off that vent. 26655d.

 

[Chris NW Ind]

I am guessing that vent cap is a plug with a hole drilled in one of the hex vents. Can someone confirm that?

Thanks, Chris B.

 

[Fritz Maurer]

It's probably supposed to be a plug, not a vent . The fuel pump will fill that thing in one revolution and gasoline will be squirting out the top.

I never had a multi-fuel 12, but i would guess that thing is meant to trap air , to act as sort of accumulator, to smooth the pulses of the fuel pump. This was accomplished on later tractors with an orificed tee screwed into the fuel tank , and a separate tank in the hood for starting.

The casting in question could also be used for starting, if the tractor was allowed to cool off on distillate. Can drain the carb, and refill it with gasoline through that hole in the top.

 

[Chris NW Ind]

Thanks. I can say I have it open when it's running and have yet to see a drop of fuel spit out.

 

[Fritz Maurer]

Well, you could take it apart and see what's in there, that might give you all the answers you need.

It apparently didn't last long after the Waukesha motors, I have a very low S/N W12 with the orifice tee into the fuel tank, with odd, ball-shaped fuel line fittings like you appear to have.

 

[rustred]

Thanks. I can say I have it open when it's running and have yet to see a drop of fuel spit out.

that is because the fuel pump is not pumping properly. that isthe same pump as the flathead fords used. the pushrod rides against the camshaft. that end wears down a bit and pressure and flow is greatly reduced. i had to weld mine up a bit on the w-12 , about 1/16 -1/8 ". then worked perfectly. crank the tractor over with the line disconnected and you will then see . there is a flow check and pressure check on fuel pumps. think it was like 3 lbs psi it needed to be good. with a good fuel pump that canister will be overflowing with an open valve. that is why the excess fuel is diverted to the main tank.

 

[Chris NW Ind]

I already did that. It's hollow. I had it off to clean all the lines.

 

[rustred]

I already did that. It's hollow. I had it off to clean all the lines.

what's hollow ?