why is there gas in my oil reservoir??

smokester · Feb 23, 2015

Title pretty much says it. My oil reservoir level didn't drop at all with my last tank of fuel. The reservoir is completely full, smells like gasoline and is obviously not the consistency of two stroke oil. Its a 98 polaris 700 rmk. Hoping somebody has seen this before. I searched the forums but couldn't find anything related, just talk about premix and such. Would it be a bad oil pump? Thanks!

sledhed · Feb 23, 2015

I would check all the oil lines to make sure they are not hooked up to the fuel pump or maybe the carburetor vent lines hooked up to the oil pump somehow? Strange.

smokester · Feb 23, 2015

sledhed said:
I would check all the oil lines to make sure they are not hooked up to the fuel pump or maybe the carburetor vent lines hooked up to the oil pump somehow? Strange.

That was the first thing I checked, sorry should have mentioned that. I actually haven't removed any of the oil lines since I bought the sled a couple years ago. They are connected to the crank case and the reed covers. Any way a bad oil cap vent could do something like that? Creating some kind of suction/siphon or something? I haven't checked that and not even sure it's possible. Weird I know.

89sandman · Feb 24, 2015

Bad reeds?

sledhead Ed · Feb 24, 2015

Check your fuel pump. If I remember right it has a Waldro fuel pump and one oil line goes to it. There might be a check valve on that oil line also. If the fuel pump needs to be rebuilt you can use the mikuni hexagon kit. The pump is discontinued from polaris.

Merlin · Feb 24, 2015

sledhead Ed said:
Check your fuel pump. If I remember right it has a Waldro fuel pump and one oil line goes to it. There might be a check valve on that oil line also. If the fuel pump needs to be rebuilt you can use the mikuni hexagon kit. The pump is discontinued from polaris.

Good catch Ed!

I never knew there was a connection between the 2 systems?

Possibly the check valve(item # 18) is faulty.

smokester · Feb 24, 2015

Wow, I had no idea that was there either! I just had the motor in my 99 tore down, basically same sled, and didn't even notice that. I'm gonna check that out tonight. Thanks guys!

sled_guy · Feb 24, 2015

Yes and make sure that line is hooked up to the right spot on the fuel pump. The 98 injected oil into the fuel pump, not in to the carb boots. Not a good design.

sled_guy

smokester · Feb 24, 2015

my hell

Okay, got to looking at it and it appears everything is hooked up right.... Only problem is there is no check valve like there obviously should be! It's a solid tube from the oil pump to the fuel pump. No check valve nor evidence that there ever was one. My guess is one of the moron previous owners deleted it for some reason and put a straight tube? Other reason I think one of the previous owners is a moron is...and not sure why I didn't notice before...I'll say because I'm new to the world of snow mobiles, but the oil cap is not even an oil gap! It's a fuel cap with the slide bars cut off! And a screw through the gauge hole! I'm pretty sure that thing is supposed to vent, which since it's not is making my problem worse.

Here's my theory, the lack of air venting in the oil tank is probably causing a lot of vacuum in the tank, especially when I'm on the throttle and the oil pump is pulling more oil from the tank. Then when I let off the throttle instead of air taking the place of the oil it's sucking fuel through the pump into the reservoir. And the lack of a check valve makes it all possible. I could be wrong, and if anybody has any better theories Id love to hear them. I'll see if I can post a picture of my "oil cap"

Merlin · Feb 24, 2015

smokester,

I pulled that parts breakdown from the Polaris online Parts Calalog. I can't say for sure that it's representative of your exact machine.

You should probably round up a service manual or get confirmation from someone who is in the know on the fuel pump port I.D. & whether the check valve needs to be installed.

Maybe sled_guy or sledhead Ed will chime in?

smokester · Feb 24, 2015

sled_guy said:
Yes and make sure that line is hooked up to the right spot on the fuel pump. The 98 injected oil into the fuel pump, not in to the carb boots. Not a good design.

sled_guy

You are correct. I must have confused the 99 with the 98. The 99 injects oil in the carb boots and the 98 does go to the fuel pump. Thanks now for the check valve that's missing and the "oil cap".

smokester · Feb 24, 2015

Merlin said:
smokester,

I pulled that parts breakdown from the Polaris online Parts Calalog. I can't say for sure that it's representative of your exact machine.

You should probably round up a service manual or get confirmation from someone who is in the know on the fuel pump port I.D. & whether the check valve needs to be installed.

Maybe sled_guy or sledhead Ed will chime in?

After you posted that I looked at the same diagram online. Maybe that was something they added in or took out at some point? That little check valve is $50 Online. By the size I would thought it would cost like $5. Is it possible the check valve mechanism is built into the fuel pump?

smokester · Feb 24, 2015

oil/gas cap

smokester · Feb 24, 2015

Alright, found the manual and under the fuel pump maintenance it says there are check valves in the fuel pump, so I'm assuming I'll need to rebuild it. So looks like I'm in for a new oil cap and a pump rebuild. Hopefully that fixes it, not sure I'll find out this season though. Why won't it snow?

Sledhead, You said I could rebuild it with that mikuni kit. Is there a specific one I should look for?

Thanks everybody

sledhead Ed · Feb 25, 2015

The check vales in the fuel pump are for fuel and operation of the fuel pump not oil. The check valve for the oil line is about 1-1.5 inches long and silver in color( aluminum). Polaris only had this setup 2or3 years then started injecting oil into the carb boots which uses round eyelet bango setup.

sled_guy · Feb 25, 2015

I may have one of those check valve thingies in the cabinet... I'll look tonight.

sled_guy

sled_guy · Feb 25, 2015

I checked, I do have one.

It is impossible to push air/oil through it from one direction. The other way you have to apply a little pressure and then it flows.

If you need it, drop me your address and I'll send it to you. I'm in Salt Lake City.

sled_guy

smokester · Feb 25, 2015

sled_guy said:
I checked, I do have one.

It is impossible to push air/oil through it from one direction. The other way you have to apply a little pressure and then it flows.

If you need it, drop me your address and I'll send it to you. I'm in Salt Lake City.

sled_guy

Awesome! Thanks! And thanks to everybody for your help!

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why is there gas in my oil reservoir??

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