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01 Ranger 500 Fuel Pump overheating and engine is stalling (Vapor Lock)

3K views 10 replies 5 participants last post by  Firestalker 
#1 · (Edited)
I have a 2001 Polaris Ranger 500 4x4, Model: A10RD50AA, Series 10. I replaced the fuel pump with an aftermarket fuel pump and it starts and runs great for about an hour. Then the engine sounds like it is starving for fuel and then dies. Removing seat and placing my hand on the fuel pump, it is extremely hot to the touch. I pour water on in to cool it down and wait 15-30 minutes and then it will start back up. Background info: I have pulled the tank and cleaned, replaced all fuel lines, replaced fuel filter, replaced pickup tube, & rebuilt Polaris Carb.

1. Why is fuel pump getting so hot and engine stopping? Am I getting too much voltage after an hour of riding? Voltage Rectifier problems?
2. Do I need to purchase another fuel pump? Polaris pumps are expensive, $220 (partzilla) vs Amazon $20-50?
3. Do I need to test the electrical system when it "Vapor Locks" and pump heats up? If so, what am I looking for? Increase in voltage ?
Any thoughts, ideas, solutions are strongly encouraged! Please advise?
Thank you!


On a side note, not related to above issue: Are the taillights supposed to come on as soon as the key is turned on? My taillights are on all the time. Headlight switch is working and is in the off position.
 
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#2 ·
I don't know if you resolved this issue, but you have my sympathy because I have the same problem. What bothers me most is the heat from the fuel pump. I'm currently charging my battery to try and eliminate the low voltage. I have tried everything on these threads that pertain to this problem. Many threads just stop and I never get the final solution. I am getting fuel tubing with heat shields, a new pump, and voltage regulator tomorrow. I'll let you know if any of those help. Also, there are posts about cracks in the fuel pickup line overheating the pump.
 
#3 ·
Thank you for response! We are not the only ones!😀
Since this post, I put the old Polaris fuel pump back on and the problem still exists. I plan on installing an insulated panel between the fuel pump and motor/exhaust pipe. Maybe that will deflect enough heat from the pump. I’m not sure if the fuel pump is heating up from an electrical issue or external heat (engine/exhaust)!
I’m also considering drilling a 1” hole near the pump in the kick panel to provide external air flow.
Please keep posting your trials/errors and I will as well! Thank you!
 
#4 ·
Does your fuel pump run continuously or does it shut off a few seconds after turning on the ignition? Mine turns out for about 3 seconds and then shuts off. And I'm having a fuel starving problem as well. But I thought the fuel pump was only supposed to prime the system and then shut off, so if yours is running continuously then that could be why it is overheating.
 
#8 · (Edited)
Fuel pump runs continuously. Voltage is applied from bat at startup for a few seconds to fill bowl and then the magneto takes over while running. The PDM controls the source input to pump. The float bowl on carb regulates flow. Pressure is ~4psi. (gravity fed). The change in source input is a safety feature to avert a big fire in case the rollover didn't kill you...
 
#9 ·
Pretty sure the pump runs continuously and the float regulates it.
Fuel pump runs continuously. Voltage is applied from bat at startup for a few seconds to fill bowl and then the magneto takes over while running. The PDM controls the source input to pump. The float bowl on carb regulates flow. Pressure is ~4psi. (gravity fed). The change in source input is a safety feature to avert a big fire in case the rollover didn't kill you...
Ok, thanks for that info... Exactly what I was looking for! Now I can start troubleshooting methodically.
 
#11 ·
Just an update in case anyone else searches for an answer and finds this thread, I think I figured out the issue. The ignition switch! It's made in two halves and 2 of the 3 little plastic latches that hold it together had come loose, causing the contacts from the front and back to separate when vibrating or hitting bumps while driving. That's why I couldn't get it sputter and cut off when trying to diagnose while sitting still, even when reserving the engine. The previous owner had already replaced the ignition a few years ago with a Polaris ignition @ $135. I went with an aftermarket this time and figure even if they don't last as long, I can still buy 10 for the same price. 🤷🏼‍♂️. Took maybe 2 minutes to replace the switch.

Thanks for the help guys
 
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