How can you tell if your fuel pump is bad? My suzuki ltf250 quadrunner does not seem to be getting any gas in the carb bowl. I tried starting it and it started from a shot of start fluid, but would only run for a second. Checked the carb bowl and it was bone dry. I pumped the throttle and nothing. Someone brought to my attention that the fuel pump might be bad? I dont understand the fuel pump on this machine, I didnt expect it to have a fuel pump, I thought the gas would just gravity feed down into the carb. I dont understand the fuel pump because I dont see any electrical wires running to it, I see an inlet tube, an outlet tube, and a small rubber tube that comes into the side and center of it? I dont get how it pumps fuel or what its purpose is if there is no motor? The only other thing I can think of is the petcock might be plugged, I blew air into the carb line and saw it bubbling inside the tank. My friend said when he pulled the main fuel line off the carb that it should have been dumping fuel out of the line. But only a little bit dumped out and it stopped. I dont see how this is possible to dump out because the fuel line runs from the petcock to an uphill angle thats higher then then tank Im not sure if it was supposed to be dumping out or not? Thanks for any help or advice!!

 

Float valve could be sticking. I pulled my Grizzly carb apart tonight for that very reason. Its done it once before. At least for my problem (which the symptons are similar), the little thing that rides on the tail of the float and opens or closes the main fuel valve to the carb was sticking inside the hole, and not allowing any gas into the carb. I could tell, because the edges were a little roughed up on it. Last time, I just bent the little hanger a little so that the float would pull it out of the hole when the fuel level in the carb was low, but tonight I sanded just a little bit of the scratches off the edge of it with a piece of 1000 grit sandpaper about the size of your finger. Very lightly just to take the nicks out of it.

I also bent the tab on the back of the float upwards some as well, but like an idiot I bent it to much because the quad runs now, but the float doesnt stay closed, and it leaks gas out the overflow valve. Which means tomorrow I have to pull it apart again to to bend that tab back down a hair.

 

The third line to your pump is most likely a vacumm line from the engine. Ther eis probably a diaphragm in there that moves with engine vacuum and draws in the fuel. I'm surprised you have anything though, my 230 is gravity fed. Pull the line off of the inlet side and see if fuel drains right from the tank. As long as the tank is above the carb, you can run a by-pass line directly from the tank to carb inlet and see if it runs with it gravity fed.

 

The pump is actually a compression pump. There should be a hose running from the pump to a nipple right in front of the carb. Compression from the engine runs the pump and "pushes" gas from the petcock to the bowl. My lt250ef was having the same problem first thing to do is check hoses for dry rot and cracks if this is good and u have the hose attached to the nipple in front of the carb then pull the fuel line from the bowl and turn the engine over. U should get a strong stream of gas from the fuel line as the engine turns over... If it is weak or isn't a steady flow (sort of spits as the engine turns over) its the pump... U can go to a lawn mower shop and get a used pump really cheap. I actually lucked out and met a guy at a gas station who was junking out some old riding lawn mowers and he gave me an old mikuni fuel pump lol. He just pulled out his pocket knife and cut the fuel lines and handed it to me. Really cool old guy... Anyway it really sounds to me like it is the fuel pump... Ps... Starting fluid is really bad for a one cylinder 4-stroke motor its better to screw off the top of your mikuni carb and pour a little gas in the carb. Question: how long has your 250 been setting up? If it has been setting for awhile the bowl may just need to be primed sometimes priming the carb a couple of times like I said above will get it going enough to ride for awhile if the pump is out... Oh and those pumps can be rebuilt pretty cheap and with little experience if you just can't find one and you don't want to buy a new one. Oh and the easiest way to get to the pump is to pull the wheel and the tank but u can also pull the back plastic and drop the tank that way. Its an easy fix and the pump should show fuel direction... Oh one more thing... The "compression" hose should come off of the forward facing nipple of the pump and is the only nipple completely accessible without removing anything else. If you have any questions just hit me up.

 

The pump is actually a compression pump. There should be a hose running from the pump to a nipple right in front of the carb. Compression from the engine runs the pump and "pushes" gas from the petcock to the bowl. My lt250ef was having the same problem first thing to do is check hoses for dry rot and cracks if this is good and u have the hose attached to the nipple in front of the carb then pull the fuel line from the bowl and turn the engine over. U should get a strong stream of gas from the fuel line as the engine turns over... If it is weak or isn't a steady flow (sort of spits as the engine turns over) its the pump... U can go to a lawn mower shop and get a used pump really cheap. I actually lucked out and met a guy at a gas station who was junking out some old riding lawn mowers and he gave me an old mikuni fuel pump lol. He just pulled out his pocket knife and cut the fuel lines and handed it to me. Really cool old guy... Anyway it really sounds to me like it is the fuel pump... Ps... Starting fluid is really bad for a one cylinder 4-stroke motor its better to screw off the top of your mikuni carb and pour a little gas in the carb. Question: how long has your 250 been setting up? If it has been setting for awhile the bowl may just need to be primed sometimes priming the carb a couple of times like I said above will get it going enough to ride for awhile if the pump is out... Oh and those pumps can be rebuilt pretty cheap and with little experience if you just can't find one and you don't want to buy a new one. Oh and the easiest way to get to the pump is to pull the wheel and the tank but u can also pull the back plastic and drop the tank that way. Its an easy fix and the pump should show fuel direction... Oh one more thing... The "compression" hose should come off of the forward facing nipple of the pump and is the only nipple completely accessible without removing anything else. If you have any questions just hit me up.