Oil & Fuel Gas in my Oil.

[ldabe]

What can cause gas to be IN the Oil?

I have a PT 422, with a gas shut off valve between gas tank and carb that I installed years ago when I bought the PT used.
The carb fuel solenoid valve ($$$) failed so I cut the tip off, disconnect the DC volt wire and had run the PT for the season that way.

At end of last year when starting the PT it began to "regurgitate" fluid (I made a topic/thread on that) out of the Breather Hose connected under the Cleaner Base (aluminum plate setting on top of carb).

I have begun to work on this beast again (luckily I am not in need of this beast very often right now).

So, where is the gas getting into the oil?
Would it be going past the Needle that is part of the Float?

Scratching my head! Love the PT422 when it is running

 

[flyerdan]

If it has a mechanical fuel pump I'd strongly suspect it has a flaw in the diaphragm that's allowing fuel into the crankcase. It can have a small tear that still allows it to make enough pressure to keep the engine running.

 

[m5040]

If it isn't the fuel pump diaphram, then it could be the carb needle/seat leaking 24-7 due to the fuel tank being higher then the engine. Just a drip would cause the intake to flood eventually making its way into a cylinder, leaking past the piston rings into the crankcase. VERY BAD CONDITION.

You could change the oil/filter then shut off that valve EVERY time you shut it down and check to see if the oil level goes up. If it does it is the fuel pump diaphram.

 

[larrydman]

I slightly overfilled my engine oil one time and started getting gas in my oil. I drained and replaced the oil and never had any more problem. I just figured it was because of these slopes I'm always on caused it. I was more careful from then on about proper oil level.

 

[ldabe]

Thanks guys, I will take all that you said in consideration.
I have drained all the oil, and will change the filter and refill the oil.

I am wondering if I should go ahead and change the needle and seat, I don't think that those parts are very expensive, and I think I can get them at the NAPA or Mom/Pop small engine shop.

Hopefully the fuel pump is still good.

 

[m5040]

In my opinion, the needle and seat is not 100% effective 100% of the time. That is why the manufacturer spent the money to put in the electric fuel shutoff. If you want to cut corners, just shut off the valve you installed and check your oil often until you make sure the fuel pump is not leaking internally.

 

[ldabe]

In my opinion, the needle and seat is not 100% effective 100% of the time. That is why the manufacturer spent the money to put in the electric fuel shutoff. If you want to cut corners, just shut off the valve you installed and check your oil often until you make sure the fuel pump is not leaking internally.

m5040, That is my plan, to shut off the gas shut off valve that I installed years ago (though I thought I shut it off every time I shut the engine down) and check the oil to see if gas migrated, each time I shut the PT down.

I have been told that
1) the electric fuel shutoff "solenoid" is to prevent backfire by one small engine parts place.
Then I was told that
2) the electric fuel shutoff "solenoid" is to stop the gas flow and "must" be operational, by another small engine parts place.

Which is right?

If the carb needle is in the seat properly, and the electric fuel shutoff solenoid is disconnected with plunger cut off, and the fuel pump is working properly, and then when the engine is shut down and I turn off the fuel shutoff valve, will there still be a possibility of gas migrating into the oil?

Also, does anyone know of an alternative than ordering from Power Trac, or Robin/Subaru for a "needle & seat"?

 

[MossRoad]

Any small engine shop that services Robin should be able to get you the needle and seat.

Also, many on-line sources.

 

[m5040]

"Which is right?

If the carb needle is in the seat properly, and the electric fuel shutoff solenoid is disconnected with plunger cut off, and the fuel pump is working properly, and then when the engine is shut down and I turn off the fuel shutoff valve, will there still be a possibility of gas migrating into the oil?

Also, does anyone know of an alternative than ordering from Power Trac, or Robin/Subaru for a "needle & seat"? "

As I stated, the needle/seat can leak. It was never intended for a gravity feed situation with constant supply and no consumption (engine off). The only thing that closes the needle is the force of the carburetor float, floating on the gasoline and pushing the needle into the seat. Any small defect in the needle/seat can cause a leak and with gravity feed, that can empty the entire fuel tank! Even the cost conscience Henry Ford put shut off valves on the model T and A's of the 20s and 30s.
When the fuel tank is above the carb, they use a second fuel shut off, not a option.
If you shut off the manual valve, there is no way for the gas to leak/migrate into the engine.
For alternate parts source, look at who makes the carburetor, and do searches from there. There are 2 types of seats (at least there used to be), a solid brass needle or a soft rubber needle (like a Viton composition) that seats better. I liked the Viton.
I don't see anyway that a electric fuel shut off can stop a backfire out the carb. Even when you shut off the valve (manual or elect), the engine will run for a few min to use up the gas in the carb.

 

[ldabe]

UGGH!!!
I drained and changed my oil. Installed new spark plugs. Cleaned carb. Put a new needle valve in (connected to float in carb...$26!!!).
Cranked the engine, let it run, ran pretty good, turned off gas cock, let fuel burn off in carb and engine to stop.

Let it sit a couple a of days, came into my garage and SMELLED GAS!

Looked to be a cracked fuel line tube connected to Fuel Pump, except it was the vacuum line!
Took the line off and gas flowed out. Pulled the Oil Dip Stick, and gas came flowing out!!

So, I bought a new Fuel Pump, which I have not installed yet. I am thinking it must be a bad Fuel Pump, but before I put the new on, I thought would get some feed back from you guys on here, since as I have stated in the past, I am not much of a mechanic and don't really know how engines work.

There was about 6 ounces of gas that came out of the vacuum line and the Oil Dip Stick hole (I have not drained the oil and replaced it yet).

Before I install the new Fuel Pump, is there another possibility of how gas is getting into the Oil?

Thanks in advance for any help on this.

 

[MossRoad]

I'd think that if there is gas in the vacuum line, the only way it can get there is if the diaphragm in the fuel pump is punctured. So instead of just sucking on the back of the diaphragm to pump the fuel, it's sucking gas through the diaphragm into the engine.

I think your diagnosis of a bad fuel pump is correct.

 

[ldabe]

Thanks MossRoad.
I was hoping that was it.
So I will go a head and change the oil again, and install the new Fuel Pump.
I think I need to replace the line from the Fuel Pump to the ??? (engine) other end, it looks cracked, but man is it hard to get to under there.

 

[Marks481]

What can cause gas to be IN the Oil? I have a PT 422, with a gas shut off valve between gas tank and carb that I installed years ago...

My aftermarket shutoff valve internals failed... I thought I was shutting things off and it was wide open. So shut the valve, pop the hose off, and make sure it is working like you think it is.

 

[ldabe]

tmarks 11, thanks, I never thought about that. It is a plastic shut off I installed years ago. So yes, I will check to make sure its operating properly.

 

[cqaigy2]

This is more about your engine, but you'll want to drain the oil, replace oil filter refill with oil DONT start the engine. Pop spark plugs out, turn the engine over kinda like you would to get the air out when replacing the hydraulic filter, don't cook your starter motor. Drain the oil, replace the oil filter and refill.



I'm assuming you musta lost the needle valve as to why you replaced it? Check to see if your valve is right side up, so i can seal, and the float is reattached correctly no junk impeding the valve from sealing. These are things i've run into in the past. It would be interesting to see what your shutoff valve looks like when it on and off

 

[ldabe]

Well, cqaigy2, I did not see your post (sadly for me) before I tried starting the engine.

I put a new "needle valve" in because I thought this is where the gas was getting by into the oil.
I put a new "fuel pump" on, and all new "fuel hoses".
I put a new "fuel shut off valve" on from TSC, a metal one(Raider Universal), not the plastic (B&S) ones.
I put new "oil" (after draining the old, that had gas in it) and a new "oil filter" on.

I checked the level of oil (story on that in a minute below) and it showed exactly where it needed to be on the steel rod dip stick.

Then, I cranked it over. It took about 4-5 times of cranking and adjusting the choke before the engine started to run.
BUT, OH MY! The engine was making a LOUD metal clanking / clunking sound while running!

I tried to shut it down AS FAST as I could, turning key off, turning the fuel shutoff valve off and putting the choke on. Seemed like forever before it shut down, though it was probably about 45-60 seconds.
Since my "solenoid fuel valve" is not working (they want over a $100 for a new one...crazy) that is, it would not draw in the plunger to allow the fuel to flow when I turned the key to on, so I cut the plunger off and reinstalled it, the engine doesn't shut off immediately when turning key off. The fuel remaining in the line from the fuel pump to the carb has to burn off.

Now, the dip stick story.
When I changed the oil, I refilled with about 800 ml of oil (it should be a total of about 1525 ml). I got side tracked with a phone call, had to go take care of another job right away. Did not get back to the PT until 2-3 days later.
Checked the oil on the dip stick, oil level was showing exactly where it should be on the full line.
After cranking the engine over, it running with the clanking / clunking metal sound, then shutting it down, I checked the oil level again. It showed exactly where it should be, BUT then, I remembered I had only put in about 800 ml!!!
But why did it show me full on the dip stick?????

Looking at the dip stick, the rubber stopper on the steel rod looks like it has slid all the way up to the bottom of the steal ring you grab to pull the dip stick out, and if the rubber stopper did (not sure exactly where that rubber stopper should be on the steel rod), then obviously the level mark on the end of the steel rod is now down further than it should be! Thus showing oil level full!!!

Now, I'm not sure if that rubber stopper moved or not, but its the only thing I can think of why it shows full oil level, but I remembered I only put in 800 ml, not 15250 ml.

So, now is my engine shot?
Or, do I put in another 700+ ml of oil and try to crank it over again?

Again, to ALL, thank you for your input and advice.

 

[cqaigy2]

I'd think the louder than normal clanking might possibly be from not having as much oil in the engine, so not dampening the engine sound as much. If it were me, with my memory span, i'd dump the oil out and put the correct amount back in. So either the engine was just noisy because of lack of oil and not damaged, or it got damaged from not having enough oil to lubricate it. Either way you're going to probably run it, after the correct amount of oil is in the engine.

 

[MossRoad]

It's dieseling for 45-60 seconds? Ouch!

Check:
Fuel cutoff solenoid.
Too high of idle setting.
Intake valves.
Timing.

 

[ponytug]

Wow. That seems like an amazingly deficient dipstick design. What a story.

If you didn't run the engine for very long, I wouldn't sweat it. In all likelihood, the oil pump had enough oil in the sump to pump some oil around the engine.

If it were me, I would just fill it up and go on my merry way, but I can see the argument for draining the existing oil out, and then adding in a known volume of oil, and double checking that the "Full" mark on the dipstick is, in fact, full.

I hear you on the pricey fuel solenoid, (The Deutz fuel solenoid is even pricier.) and I wonder if there are 3rd party substitutes available. 45-60 seconds of run on would get old quickly for me, but YMMV...

All the best,

Peter

 

[ldabe]

MossRoad, the fuel cutoff solenoid does not work. I have never messed with the idle setting.
I wouldn't know what to do with the intake valves or timing setting.

Ponytug, looks like I am going to take your advice. I'll drain oil again. Make sure amount called for is put in and give it a shot!

Does anyone have a pic of their Oil Dip Stick? I would like to see where the rubber is positioned on the steel rod.