Polaris 300 Carb. Hose Question - Vent or Vacum?
#1
Polaris 300 Carb. Hose Question - Vent or Vacum?
I am reposting part of a previous string as I believe it was not properly titled.
I've got this '98 Xplorer that I have been putting back together. I've got it almost reassembled but am have a problem getting it running. I can get the engine to run on a squirt of starter fluid but as soon as the starter fluid runs out it dies. My fuel lines are clear and my carb bowl is full of fuel. I just overhauled my carb so I know its clean inside and out. The only thing that is bugging me is that I can't determine where a brass fitting on the right-hand side of the carb (if your sitting on the bike) that is parallel to the ground should be connected. This fitting I suspect is a vacum fitting for the carb but I can figure out where the hose should connect to on the other end? Any thoughts would be appreciated. I have done a few tests and have found that when I blow a short blast of air through this fitting it allows the engine to run for a brief minute. So I suspect it is a pulse or vaccum fitting. I have provided a picture of the fitting in question. Anyone with a 250 - 400 cc bike would probably have the same carb. I have labeled the fittings in the picture with what I believe them to be. The only one not shown is the overflow fitting on the carb bowl that I believe is connected via a T-connector to the black plastic fitting at the top of my picture.
Any ideas?Carb Pic
I've got this '98 Xplorer that I have been putting back together. I've got it almost reassembled but am have a problem getting it running. I can get the engine to run on a squirt of starter fluid but as soon as the starter fluid runs out it dies. My fuel lines are clear and my carb bowl is full of fuel. I just overhauled my carb so I know its clean inside and out. The only thing that is bugging me is that I can't determine where a brass fitting on the right-hand side of the carb (if your sitting on the bike) that is parallel to the ground should be connected. This fitting I suspect is a vacum fitting for the carb but I can figure out where the hose should connect to on the other end? Any thoughts would be appreciated. I have done a few tests and have found that when I blow a short blast of air through this fitting it allows the engine to run for a brief minute. So I suspect it is a pulse or vaccum fitting. I have provided a picture of the fitting in question. Anyone with a 250 - 400 cc bike would probably have the same carb. I have labeled the fittings in the picture with what I believe them to be. The only one not shown is the overflow fitting on the carb bowl that I believe is connected via a T-connector to the black plastic fitting at the top of my picture.
Any ideas?Carb Pic
#2
Polaris 300 Carb. Hose Question - Vent or Vacum?
I dont know how much help this will be, but my son's 1996 has a hose coming off the brass fitting, it goes under the intake of the carb. Then to a Tee connector on the left side of the bike. I lose where they go after this. One looks like it goes to the bottom of the carb or that area. The other goes onto something that looks like a disc type fuel filter, or some round plastic device, then another hose comes off the other side of the disc.
I will be tearing this machine down sometime in the next few weeks, I will make a note of where these lines end up and post it for you.
Good luck!
I will be tearing this machine down sometime in the next few weeks, I will make a note of where these lines end up and post it for you.
Good luck!
#3
Polaris 300 Carb. Hose Question - Vent or Vacum?
That is helpful as it tells me that my thinking was wrong. I thought the black plastic fitting connected to the the tee. The round disc you see in your line is a check-valve that prevents water from backing up into the carb. The one you see coming from under the carb will connect to that T-fitting as well and are just vent lines. Can you, by any chance, tell me where the black fitting at the top of my picture leads to on your ATV? It is a black plastic fitting with a 90 degree elbow in it. It sounds like that may be the one that I am confusing for a vent or vacum line. Thanks alot for your response. That has been a big help!
#4
#5
Polaris 300 Carb. Hose Question - Vent or Vacum?
I will hook the brass fitting to a t-connector as well as the vent line from the carb bowl. I still have one fitting left. The black fitting with the 90 degree elbow at the top of the picture that i thought was a vent line sounds to me now like it is not a vent. Is it possible that this hooks to the line coming out of the gas tank? That doesn't seem to make a whole lot of sense to me as the gas tanks on the 2-strokes I have worked on always seem to vent down to the handlebars to relieve pressure and if there is some overflow it goes down through the handlbars to the ground. Also, that elbow opens into the choke plunger area. If any gas came out of the tank and went into the choke area it would not be premix with oil and might ruin the engine. That fitting must connect to something else on the engine.
#7
Polaris 300 Carb. Hose Question - Vent or Vacum?
The outlet on the bottom of the carb connects with a T-fitting to the brass outlet on the top of the carb. After the t-fitting there is a 1-way check valve. Make sure the check valve is placed in the line in the right direction. There is a right way and a wrong way to install it. Blow through the check valve with your mouth. The end that you can blow through is the end that is closest to the T-fitting. The other end is furthest away. This not only, prevents water from entering the carb, but also lets the carb breath/vent and somehow (I don't know how) balances the air/fuel mixture.
The last fitting on the top back of the carb (Black 90 degree elbow) just vents into a hole in the frame just behind the fuel tank.
Hope this helps. I ended up buying another Xplorer for parts and to find out how the carb is set up. I got no love here!
The last fitting on the top back of the carb (Black 90 degree elbow) just vents into a hole in the frame just behind the fuel tank.
Hope this helps. I ended up buying another Xplorer for parts and to find out how the carb is set up. I got no love here!
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#8
Polaris 300 Carb. Hose Question - Vent or Vacum?
Hope this helps. I ended up buying another Xplorer for parts and to find out how the carb is set up. I got no love here!
#9
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Polaris Ask an Expert! In fond memory of Old Polaris Tech.
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