Because of the 39mm Kehin carb on my Sport (it doesn't like to have fuel sit around in the float bowl for too long) I run it almost dry before I put it away. I've never had a problem on start up since I started doing that. Just turn the gas on, wait a few seconds and it fires right up.

I'd bet that the CV (Constant Velocity) carbs on the four strokes might be the problem.

 

I think I might be able to help you guys out.

1) reserve IS in the same tank. It simply is a port that drains out of the lowest part of the tank. The fuel outlet when in the 'on' position, will leave about an inch (or a little more) fuel at the bottom of the tank when it runs dry.

2) the reason the Xplorer's don't have that problem is they have a different design carbureter, and no 'booster' pump to get fuel to it.

3) Here is the answer you were waiting for. If you run out of gas, here is the trick to get it going. WOrks on 90% of smaller engines.
First, try to start it like usual, just in case you get lucky. If you don't, remove the seat. Find the air intake horn. On some of the machines, this is just behind the gas tank. Other machines have a snorkel going higher up, and are hard to get at. Anyway, put your hand over the intake. Now crank over the engine. Pump the throttle if you can (a friend or third hand helps). You should feel the engine vacuum pulling on your hand. Pull your hand away every couple seconds, to see if it tries to start. Don't crank for so long you overheat the starter.
If you can't get to the end of the intake, you might try removing the air cleaner, and plugging the intake right there. Basically, what you are trying to do, is create enough vacuum, that the carb will literally suck the fuel into it. Trust me, it works 90% of the time. Sometimes it works too good, and floods it. If you hear a sputter at all, that usually means you got at least some fuel into the carb. Oh, and I have had better luck, if the engine is warm, doing this with the choke OFF, as flooding is less likely.

 

Full choke, full throttle, and let it crank until it starts or you hear it trying to. Then turn the choke off and give it just a little gas. That's how I start mine. Having the throttle and choke wide open allows the gas to fill the carb a lot faster. You aren't going to flood it because there is no gas to flood it with. It gets things going quicker. Putting your hand over the air intake is just a manual choke and would also work well.

 

Actually, depending on what carb you have on your bike, putting your hand over the intake can be far superior to choking it. The reason I say this, is many, if not most carbs any more don't have a 'choke', they have an 'enrichening valve'. This opens up a little port allowing more fuel into the mix, but doesn't actually increase vacuum. Blocking the intake allows the vacuum of the enging to literally suck fuel through the system. In my experience, it has worked better than simply choking it, unless your particular carb has a choke butterfly.

 

The 4 stroke POLARIS'S have a fuel pump and if you run out of fuel put it on reserve use full choke and try to start 99% of the time it will start but if it doesn't crank it for alittle bit and let it sit for 3 min. and it should siphon enough fuel to start right off. If you try to start it with out full choke first they can be a problem to start just give it time to siphon some fuel into the fuel pump and it will start.When we first start them out of the crate we put the fuel in before any thing else to give it time to siphon the fuel

 

Here's maybe and idea for you. As soon as it starts to sputter turn it off. Switch to reserve and restart. Should be enough gas left to make it fire and run a few seconds, enough time to pick up the fuel.

 

I don't know if the Polaris fuel valve is like a normal motorcycle or not but with a normal fuel control there is a long tube and a short tube, the longer of the two naturaly sticks up in the tank higher than the other, being the main fuel supply, if you always run on the main and never switch to reserve any water that is in the tank stays there untill you run out and switch to reserve, guess what, the engine won't burn water, if when you fill up run for a little while on reserve then switch back to the main, this will insure that if any water or other trash is in the tank it will show up right away not 20 miles from god knows where. Just a hint, been there done that. See Ya.

 

One possibility rebuild the fuel pump. That rubber diafram gets tired after while.

Second in search of more power I kept running out of gas. Tank full but the fuel bowl would suck dry. Filter, pump, lines nothing helped until I removed the vacum operated pump and replaced it with the electric pump from a 79 Subaru. 3.5 psi and loads of volume. The needle handles it well and I get instant starts and no more lean out on top end.

PS Don't use a pump from a fuel injected motor. Way to much pressure.

 

I found out that on my '00 SP500, that after it sits a month or two, especially in the winter, no amount of cranking will start it. My dealer told me to drain the bowl(thankfully, Polaris has provided a drain screw and clear drain tube), then refill with fresh gas from the tank. After a little fiddling with the choke and throttle, it starts right up.

Good luck, and I hope this helps.

P.S. On my old '84 TRX200, I only used the reserve when I ran out of gas. Eventually, the condensation in the bottom of the tank rusted a hole through it, and forced me to purchase a new tank. I then discovered that the fuel screen was ruined as well. Since then I run on reserve for a while after filling the tank to keep condensation to a minimum.

 

I found the cure for the no fuel guage problem on the polaris 400 & 500.
go out and measure the depth of your tank, then take that information to the nearest used snomobile shop and locate a gas tank cap with the fuel guage in it that comes as close as possible to that measurement.

this is a reasonably acurate method of keeping an eye on the juice, and you can get one with the polaris emblem in it so it looks factory.

hope it helps.