1936 I12 gas in oil

[STP36500]

I have the 1936 Adams motor grader that I purchased last year at auction. I have started this rig once in November of last year and then 3 times this spring. I only ran it minimally as I am checking fluids and making sure everything is ready to start grading. Well yesterday I started the rig and while it was warming up I checked the oil pressure and it was very low, like below 10 psi.

I stopped the engine and opened the oil full level plug on the side of the oil pan. There are two oil level plugs I believe that are about 1/2 in different elevations. When I open this upper plug, liquid came gushing out. It looked like very thin oil and smelled like gas. I then drained all the oil out and replaced with non-detergent 30W oil. Once started I had oil pressure again at about 40 PSI.

What causes gas to get into the oil? The tractor does have a electric fuel pump. If the electric pump continues to pump then I would think it would flood the carb/engine and would be difficult to start. This motor starts and runs fine every time that I have used started it and now wondering if this oil in the gas was from previous owner or only happened in the minimal times that I started it.

I am still totally new to this engine and appreciate any input that you guys can provide on what to check and look for to not let this happen again. Thoughts/ideas? Thanks!!!!

 

[old]

That is a common problem with tractors due to carb float hanging up and letting to much gas into the carb when not running. I have drained out more then 5 gal of gas/oil mix in a Ford 9N before because the guy didn't shut off the gas when he parked it

 

[rustred]

you say I12, so i presume u are talking engine like the w-12 has. this engine has a down draft carburator and if it is flooding is lots more likely to dilute the gas. and from factory these engines have a manual fuel pump, and if that diaphram cracks the gas will run right in to the oil pan. plus there is two valves in the pump that would have to be not holding. and if you are new to it then i might have been comtaminated before.

 

[rustred]

fords better idea, self contained fuel leak stays in tractor. environmentally friendly .

 

[STP36500]

So when not running the fuel in the carb drains into engine? Since this is an electric fuel pump this should not happen as the fuel filter is very low with gas tank at back of grader and cannot drain into the engine unless fuel pump is running.

I will keep my eye on the oil and check to see if this is happening now.

 

[old]

If the fuel tank sits higher then the carb it can/will over fill the carb if the float needle does not close up as it should and that can cause fuel in the oil. Seen it on many different tractors.

 

[rustred]

to clear things up answer what engine this is, i asked if down draft carburator? it is not very common to have this happen with an updraft carb.

 

[Jim Becker]

As he said, it is an I-12. The engine is substantially the same as any 12-Series tractor, with a down draft carburetor. It does not have the mechanical fuel pump, eliminating the possibility of fuel leaking from it directly into the crankcase.

It appears that he is using a high-mounted temporary fuel tank that could allow fuel to leak past the carburetor float valve and into the crankcase via the cylinders. However, the temporary tank looks small. It looks like he would have had to refill it to get anything like 5 gallons of gas into the oil. The other possibility is the electric pump ran excess fuel from the installed tank into the carburetor, giving the same effect. Presumably this was from before the temporary tank was installed and before he bought it.

Pictures of this machine are in an older thread:
https://forums.yesterdaystractors.com/viewtopic.php?t=1469193

 

[used red MN]

For others I think it has been established by his other posts that the engine is a power unit version of an F12 engine. So I think if your fuel tank is completely full or near that the level of fuel would be higher than the carburetor so fuel could flow past a leaking needle and seat and get in the engine. So I also see you have a valve on the bottom of the tank. ..see link to posted video at 20 seconds.. If that has been kept closed while it is not running you should not have any problem. This will be true as long as the fuel is not routed through the original mechanical pump on the engine as has been stated. The gas downed oil could have very well came from operation by the previous owner. If you want a couple of PDF manuals that pertain to operation and parts for an Farmall F12 tractor email me from Classic View. Posting a couple of good pictures with good light of both sides of the engine would be quite helpful.
YT post with start up video

 

[rustred]

yes i am very familiar with this engine . i did a complete engine rebuild on my W12. all to the way it was factory. just wanted to make sure on the same page. i look for what is related to the engine, not just a general answer.

 

[STP36500]

The

pictures provided by Mecum auction shows a small red tank shown on the attached picture. This is no longer there and now has a electric fuel pump and I have used the larger original tank. The original tank is impossible to gravity drain into the carb, but this other tank could. Hopefully, that was the culprit and is now fixed. I will definitely keep an eye on this.

Thank you very much for the reply!

 

[STP36500]

The pictures that show the small tank are from Mecum and the machine now has an electric fuel pump and I am using the large fuel tank on the rear. I am thinking
that the fuel could have gotten into the oil from when the previous owner used this small tank. I can't think if a way for gravity to do this now.

 

[STP36500]

This is an I-12 serial number IS-1507. Any and all of your info is greatly appreciated.

 

[old]

Yellow tank as in behind the seat?? Looks like if it is filled up all the way it could/would gravity feed the carb and cause a gas in the oil problem

 

[STP36500]

I will look at that again, but I have closed the valve each time I have used it. I have only added 2.5 gallon of gas to date. I have only started this four times and the first was with gas from a water bottle vs the gas tank. Hopefully this is all from previous owner. We'll see. Thanks!

 

[John M]

Whats the PSI and GPM on your pump?

 

[STP36500]

Yes that tank behind the seat. Looking at it again, if it was full it would potentially gravity to the carb. I have only put about 2.5 gallons in this tank and have closed the valve at the tank every time. I will keep on a lookout.

 

[STP36500]

This is a information from Amazon when I searched for the pump.

Universal Fuel Pump
Part #42S
42 GPH or 0.7 GPM
2-3.5 PSI

 

[Ron W]

So if you have an electric fuel pump going to the Carb on an F-12/I-12/W-12/O-12/F-14/I-14/W-14/O-14 or any combination there after AND you don't have a bypass return line to the tank, you are in trouble. The carb will not take much fuel pressure to force the needle valve open. That is why all the machines had at TEE or in the case of a Kerosene a return Valve (sticking through the hood) to let the over flow head back to the tank. ALSO, the fuel pump runs off the camshaft and only pumps once every two revolutions of the crankshaft.

If you mount a tank more than 12 above the fuel bowl, it will leak past the needle valve. I have done this before and somewhere around here is a Service Bulleting that uses that to double check the float operation. If I find it I will scan it and post it.

So if you use a fuel pump, make a bypass. You will be golden.

If you don't want a fuel pump, mount the tank usable gas level no more than 6 above the carb and use a 5/16 pipe. Steel preferred and safest.

 

[36F30]

(quoted from post at 17:23:18 04/12/21) So if you have an electric fuel pump going to the Carb on an F-12/I-12/W-12/O-12/F-14/I-14/W-14/O-14 or any combination there after AND you don't have a bypass return line to the tank, you are in trouble. The carb will not take much fuel pressure to force the needle valve open. That is why all the machines had at TEE or in the case of a Kerosene a return Valve (sticking through the hood) to let the over flow head back to the tank. ALSO, the fuel pump runs off the camshaft and only pumps once every two revolutions of the crankshaft.

If you mount a tank more than 12 above the fuel bowl, it will leak past the needle valve. I have done this before and somewhere around here is a Service Bulleting that uses that to double check the float operation. If I find it I will scan it and post it.

So if you use a fuel pump, make a bypass. You will be golden.

If you don't want a fuel pump, mount the tank usable gas level no more than 6 above the carb and use a 5/16 pipe. Steel preferred and safest.

Ron is correct, no way that carb could hold back an electric fuel pump without a reflow tee to return excess fuel back to the tank.

 

[STP36500]

(quoted from post at 18:00:14 04/12/21)

(quoted from post at 17:23:18 04/12/21) So if you have an electric fuel pump going to the Carb on an F-12/I-12/W-12/O-12/F-14/I-14/W-14/O-14 or any combination there after AND you don't have a bypass return line to the tank, you are in trouble. The carb will not take much fuel pressure to force the needle valve open. That is why all the machines had at TEE or in the case of a Kerosene a return Valve (sticking through the hood) to let the over flow head back to the tank. ALSO, the fuel pump runs off the camshaft and only pumps once every two revolutions of the crankshaft.

If you mount a tank more than 12 above the fuel bowl, it will leak past the needle valve. I have done this before and somewhere around here is a Service Bulleting that uses that to double check the float operation. If I find it I will scan it and post it.

So if you use a fuel pump, make a bypass. You will be golden.

If you don't want a fuel pump, mount the tank usable gas level no more than 6 above the carb and use a 5/16 pipe. Steel preferred and safest.

Ron is correct, no way that carb could hold back an electric fuel pump without a reflow tee to return excess fuel back to the tank.

Where should I place the tee and return to the tank? My fuel line generally runs along the lower left part of the engine and then goes up near front of engine and goes back into the carb. Hopefully you can see the fuel line in the picture.

 

[STP36500]

(quoted from post at 18:00:14 04/12/21)

(quoted from post at 17:23:18 04/12/21) So if you have an electric fuel pump going to the Carb on an F-12/I-12/W-12/O-12/F-14/I-14/W-14/O-14 or any combination there after AND you don't have a bypass return line to the tank, you are in trouble. The carb will not take much fuel pressure to force the needle valve open. That is why all the machines had at TEE or in the case of a Kerosene a return Valve (sticking through the hood) to let the over flow head back to the tank. ALSO, the fuel pump runs off the camshaft and only pumps once every two revolutions of the crankshaft.

If you mount a tank more than 12 above the fuel bowl, it will leak past the needle valve. I have done this before and somewhere around here is a Service Bulleting that uses that to double check the float operation. If I find it I will scan it and post it.

So if you use a fuel pump, make a bypass. You will be golden.

If you don't want a fuel pump, mount the tank usable gas level no more than 6 above the carb and use a 5/16 pipe. Steel preferred and safest.

Ron is correct, no way that carb could hold back an electric fuel pump without a reflow tee to return excess fuel back to the tank.

Does it matter where the tee and bypass are located? or is it just somewhere downstream? Please let me know option 1 or option 2 shown in the picture below.

ALSO, what would be the best way to plumb this back into this heavy duty tank? drill and tap another valve near the top?

 

[36F30]

(quoted from post at 15:15:01 04/13/21)

(quoted from post at 18:00:14 04/12/21)

(quoted from post at 17:23:18 04/12/21) So if you have an electric fuel pump going to the Carb on an F-12/I-12/W-12/O-12/F-14/I-14/W-14/O-14 or any combination there after AND you don't have a bypass return line to the tank, you are in trouble. The carb will not take much fuel pressure to force the needle valve open. That is why all the machines had at TEE or in the case of a Kerosene a return Valve (sticking through the hood) to let the over flow head back to the tank. ALSO, the fuel pump runs off the camshaft and only pumps once every two revolutions of the crankshaft.

If you mount a tank more than 12 above the fuel bowl, it will leak past the needle valve. I have done this before and somewhere around here is a Service Bulleting that uses that to double check the float operation. If I find it I will scan it and post it.

So if you use a fuel pump, make a bypass. You will be golden.

If you don't want a fuel pump, mount the tank usable gas level no more than 6 above the carb and use a 5/16 pipe. Steel preferred and safest.

Ron is correct, no way that carb could hold back an electric fuel pump without a reflow tee to return excess fuel back to the tank.

Does it matter where the tee and bypass are located? or is it just somewhere downstream? Please let me know option 1 or option 2 shown in the picture below.

ALSO, what would be the best way to plumb this back into this heavy duty tank? drill and tap another valve near the top?

lets see if this vid of my F12 works. the fuel pump line goes to the tee then one side of the tee goes to the carb and the other back into the tank, It's not a standard tee as it has a restriction in it ensure flow to the carb when it needs it.