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Discussion Starter · #1 ·
I have an 07 660 with this problem
the first time it felt like it vapor locked ( temp was around 100 and we were climbing some good mnts. It would stop and we pulled the passenger seat let it cool off and did good as long as you were moving, if you slowed down or idled it would do it again. Felt the gas tank and was really hot, and no fuel in the filter, so I wrapped the tank with some thin insulation stuff hoping to fix the problem. Went out this week end and it worked good until this morning ( 60 degrees ) started acting like it was starving for fuel, but would run really ruff seating still, but not as soon as you let off the fuel, If we pulled the seat and the engine box looking around, we could put it all back together and it run great the rest of the day!!
Any ideas on what to check?
 

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Could check the fuel lines for kinking,since your situation changes after you mess with the seat.
Could wrap the fuel hose from the pump to the carb too.
 

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pretty common issue if you look around this forum, i had the same issue when mowing for a couple hours. it would quit i would take the seats and engine covers off for a while and it would start. the fuel pump gets hot and stops drawing the fuel. searching only came up with "buy a kit from a company that doesnt exist anymore". so i got some longer line and mounted the pump to the bar by the tank and got rid of the return bypass line that tee's off the feed of the pump to the carb. do this at your own risk i dont know if its too much fuel at idle but i mow stop and go all the time and idle all the time when i am cutting brush for the club trails and its not shut down once since.
 

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Discussion Starter · #5 ·
so what would you wrap the hoses in, or are there other hose out there to replace the oem hoses?
Not sure what or how to move the fuel pump, and what could or could not be left off, hoses all seam to be clear/no pinching
 

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I just had the same problem.........removing my "Ride on" dust cover seemed to help cool everything down a little bit and it ran better........in the process of upgrading to Alba fuel pump and will change fuel filter......also checked valve clearances and idle speed on carb which seemed ok. Won't get to test it all for another three weeks. With 6000 miles on it I figured a new fuel pump can't hurt.
 

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........ i got some longer line and mounted the pump to the bar by the tank and got rid of the return bypass line that tee's off the feed of the pump to the carb. do this at your own risk i dont know if its too much fuel at idle ............
Lowering the pump is a very good thing to do. This will help greatly in the priming of the pump and continue pumping if an air bubble shows up between tank and pump. All fuel pumps push fuel better than they suck air. It makes for a much shorter distance to lift the fuel into the pump.

Beware of eliminating the return line though. It acts as a very low pressure regulation scheme by making the fuel pressure head never exceed the height of the return line above the carb float valve. The stock carb was designed for a gravity feed system (motorcycle gas tank a few inches above the carb). They often cannot handle a small overpressure. If you do this, monitor the float bowl overflow hose hanging along side of the carb to make sure that it does not make a puddle of fuel on the belly pan.
 

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i will take a look. i have seen a ton of pump setups like this on mowers, welders, etc..... and none had a bypass like that, to me it seems like something you wouldnt want.
 

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I have an 08 450 and just had this same issue on 3 day ride out in the middle of no where. Weeks prior to the ride I had replaced the fuel pump and new fuel filter. I relocated the filter on top of the tank for easy change out the next time as well. We were in 90 degree temps and it would intermittently not start after sitting for a few minutes. I to have a Ride On cover. If I pulled that back, as well as removing the passenger seat and let it sit, it would then start again. I noticed when it would not start, the pump was not pulling any fuel through the filter. At first I thought the carb was vapor locking, but i'm wondering if it was the pump getting too hot? I may look into relocating my pump as mentioned above.
 

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i will take a look. i have seen a ton of pump setups like this on mowers, welders, etc..... and none had a bypass like that, to me it seems like something you wouldnt want.
Very often these types of machinery have gravity fed supplies; a tank higher than the motor. This is just like the motorcycle that the carb was designed for, no fuel pump, no return line.

It can be improved by raising the return loop higher above the pump. The return leg of the Y fitting should be pointing upward and the return hose should loop upward at least a few inches (more is more pressure) before it turns down and returns to the tank.

The service manual has a very poor diagram as to how this hose is routed. They show it going down at the Y fitting. I have seen many fuel problems cured by simply rerouting that hose. The highest point of the fuel supply level determines the pressure at the carburetor, just like the height of the water level in the water tower tank above your tap in a city water supply.
 

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was talking about ones on a welder and a couple brush mowers we have and they have tanks lower than the engine and are made for more movement and weird angles and none of those have the return.
 

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was talking about ones on a welder and a couple brush mowers we have and they have tanks lower than the engine and are made for more movement and weird angles and none of those have the return.
Well, then take the return line out and plug it up if you like. Do worry about it if you smell gas though. It is not my worry.
 

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next time i ride it i will take a look at the vent and see if they have anything coming out, if so i will run a new bypass, if not i dont think im going to worry about it unless it acts like its rich at idle.
 

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Very often these types of machinery have gravity fed supplies; a tank higher than the motor. This is just like the motorcycle that the carb was designed for, no fuel pump, no return line.

It can be improved by raising the return loop higher above the pump. The return leg of the Y fitting should be pointing upward and the return hose should loop upward at least a few inches (more is more pressure) before it turns down and returns to the tank.

The service manual has a very poor diagram as to how this hose is routed. They show it going down at the Y fitting. I have seen many fuel problems cured by simply rerouting that hose. The highest point of the fuel supply level determines the pressure at the carburetor, just like the height of the water level in the water tower tank above your tap in a city water supply.
Hello, I realize this is an old post but i was hoping you could describe or possibly even provide a picture of the "Return Loop" you speak of. When I got my rhino it had been sitting outside unattended for a couple years and was in shambles. I thought I had it figured out until reading this thread. Any info helps. Thanks
 
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