99 Polaris Xplorer 300 Acting Like It's Running Out of Fuel?

[SwampSurvivor]

Having a weird issue with my 99 Polaris Xplorer 300. It's of the 2smoke variety.

Runs great. Carb rebuilt and dialed in by someone who knows what they're doing (not me). Plug isn't reading lean.

If I nail it from sitting still, it runs great. If I'm on a trail and on/off the throttle constantly, it's fine.

It seems if I run constant throttle for more than 1/4 mile, it starts acting like it's running very lean or out of fuel. In fact, a while back, one of my friends thought it was funny to turn off the fuel shutoff and it sounds exactly the same. If I stop and let it idle, it will run fine again. Or if I keep going it will start bogging out like it has no gas. And sitting lets it figure itself out and it's fine again.

I don't believe it's a carb issue. If it was a carb issue, seems like it would have lean issues at wide open throttle or flood / require choke at idle. Runs great except on extended sustained speed.

 

[nwjones18]

I'd say checked for kinked/clogged fuel line or pickup in tank, or a gas cap on the tank that isn't venting properly. My money is on the fuel cap. See if it does it with the cap loose.

 

[2010Civic]

Does it have a fuel pump?

 

[Slick3914]

Fuel tank vent

 

[SwampSurvivor]

I'd say checked for kinked/clogged fuel line or pickup in tank, or a gas cap on the tank that isn't venting properly. My money is on the fuel cap. See if it does it with the cap loose.

Fuel tank vent

I'm definitely going to run with the cap a bit loose next time I'm taking it out! That does seems to make sense that it's not venting right.
It does have new fuel lines and I checked that they're staying together and not kinking and killing flow. Also has new fuel filter too.

 

[SwampSurvivor]

Does it have a fuel pump?

Gravity feed carburetor

 

[SwampSurvivor]

I'd say checked for kinked/clogged fuel line or pickup in tank, or a gas cap on the tank that isn't venting properly. My money is on the fuel cap. See if it does it with the cap loose.

I think that's the case. I did some riding over the weekend and got out on a main section of trail and held it open for quite a ways. It started to act like it was running out of fuel, I opened the cap for a second and closed it and it came right back to life. Then I did the trip across the property a few times with the cap opened and no issue.

I don't believe the fill cap itself has a vent but the tank does. So I'm going to have to try to get in there and see what's going on.

 

[oil pan 4]

Seems you know the conditions that make it act like it's running out of fuel.
See if there's a kinked fuel line, if no...
Let the fuel run down to a 1/3 of a tank or less and slightly unscrew the gas cap enough to venbthe tank and see if it still acts like it's running out of fuel.
Sounds like you are running the fuel out of the carb faster than it can refill, but why.

 

[nwjones18]

I think that's the case. I did some riding over the weekend and got out on a main section of trail and held it open for quite a ways. It started to act like it was running out of fuel, I opened the cap for a second and closed it and it came right back to life. Then I did the trip across the property a few times with the cap opened and no issue.

I don't believe the fill cap itself has a vent but the tank does. So I'm going to have to try to get in there and see what's going on.

Sounds good. I don't know about Polaris's, but the cap is vented on my Yamaha's.

 

[BrianF]

I had the same issue with my 2000 Magnum 500 in the dead of winter. Tank vent has small line that runs to the headlight pod. Mine chafed through and was icing up. Pop up the plastics abit to find it.