I bought another 2003 660 with 1,500 miles $3K for my dad and sold his old one that was needing some work with 3800 miles. The good news is I was able to break even on the deal and the low mileage one rides much nicer and is "tighter" as it was never used to plow. All in all, a much nicer machine.
I have spent hours/days researching and reading carb-tuning threads from all over the internet for this machine. I spent all afternoon Saturday trying to get the fuel screw adjusted to smooth throttle operation and I just can't get it right. My Dad lives 3 1/2 hours away so I don't have immediate access to the machine.
Before swapping out the machines, I did a bunch of maintenance and cleaned the carb as the lower mileage 660 was leaking gas on my driveway out of the carb overflow. The previous owner ran the carb dry every time he put it in the garage so the o-rings were all dried out and crusty. I put a Moose carb kit in it (the same one I put in his previous Griz and it ran like crazy) and now I'm having a very hard time getting rid of a stumble in the low throttle range. Seems to be right where it is transitioning from the pilot jet circuit to the needle jet circuit. He is using it to plow and ride for fun. It stumbles at 4-6 mph in low and 7-10 mph in high range but runs like a raped ape as you continue to push the throttle! This issue makes it very difficult to plow with as this is the main operating range.
When I took out the fuel screw, it was set at 3 3/4 turns (which seemed to me like a very rich mix for 900 feet of elevation). If I remember correctly, tuning the fuel screw should start at 2 1/2 turns and adjust from there correct? It ran strong with no hesitation when I picked it up. He had the carb serviced a long time ago and it was done at a dealer so I assume that was how it was set from the dealer service.
Anyway, I cleaned the carb thoroughly and installed the new kit. As many of you know, adjusting the fuel screw on a 660 is a real PITA without taking the carb off or at least loosening and rotating it. I made a short screwdriver out of a nail and a short piece of dowel to make adjustments without tearing things apart. I have adjusted from 2 turns out all the way to 4 turns out in 1/4 turn increments and I cannot get rid of the stumble. At 2 1/2 turns out, it barely stays running as I apply the throttle until it hits the needle jet circuit. At that point, it runs and accelerates great. When I got to around 3 1/2 turns out, it was better but still not a clean transition to the needle jet throttle range. The diaphragm appeared to be in good shape as well as the intake boots between the air box and the engine so I don't think I have any issues there.
Does anyone have any tips I can use next time I get down to his house to work on it? I'm guessing I will need to re-clean and start from scratch. I also forgot to check to see if the reverse/override limiter (does it have one?) was bypassed or not. Could that have anything to do with it?
Thanks in advance for any tips or help on this! I need some ideas for my next trip down to work on it.
I have spent hours/days researching and reading carb-tuning threads from all over the internet for this machine. I spent all afternoon Saturday trying to get the fuel screw adjusted to smooth throttle operation and I just can't get it right. My Dad lives 3 1/2 hours away so I don't have immediate access to the machine.
Before swapping out the machines, I did a bunch of maintenance and cleaned the carb as the lower mileage 660 was leaking gas on my driveway out of the carb overflow. The previous owner ran the carb dry every time he put it in the garage so the o-rings were all dried out and crusty. I put a Moose carb kit in it (the same one I put in his previous Griz and it ran like crazy) and now I'm having a very hard time getting rid of a stumble in the low throttle range. Seems to be right where it is transitioning from the pilot jet circuit to the needle jet circuit. He is using it to plow and ride for fun. It stumbles at 4-6 mph in low and 7-10 mph in high range but runs like a raped ape as you continue to push the throttle! This issue makes it very difficult to plow with as this is the main operating range.
When I took out the fuel screw, it was set at 3 3/4 turns (which seemed to me like a very rich mix for 900 feet of elevation). If I remember correctly, tuning the fuel screw should start at 2 1/2 turns and adjust from there correct? It ran strong with no hesitation when I picked it up. He had the carb serviced a long time ago and it was done at a dealer so I assume that was how it was set from the dealer service.
Anyway, I cleaned the carb thoroughly and installed the new kit. As many of you know, adjusting the fuel screw on a 660 is a real PITA without taking the carb off or at least loosening and rotating it. I made a short screwdriver out of a nail and a short piece of dowel to make adjustments without tearing things apart. I have adjusted from 2 turns out all the way to 4 turns out in 1/4 turn increments and I cannot get rid of the stumble. At 2 1/2 turns out, it barely stays running as I apply the throttle until it hits the needle jet circuit. At that point, it runs and accelerates great. When I got to around 3 1/2 turns out, it was better but still not a clean transition to the needle jet throttle range. The diaphragm appeared to be in good shape as well as the intake boots between the air box and the engine so I don't think I have any issues there.
Does anyone have any tips I can use next time I get down to his house to work on it? I'm guessing I will need to re-clean and start from scratch. I also forgot to check to see if the reverse/override limiter (does it have one?) was bypassed or not. Could that have anything to do with it?
Thanks in advance for any tips or help on this! I need some ideas for my next trip down to work on it.
