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Discussion Starter · #1 ·
Hey guys, I'm new here. I was directed to this forum when I ran into a little bit of trouble with my sled.

So I bought a 97 mxz 670 a while back. It was a chassis and boxes of parts. It cost me a case of beer for a project sled. So after some investigating with the original owner who had completely dismantled the engine to figure out why he did that it turns out the seal on the water pump side of the rotary valve shaft was leaking and he thought it was the inner seals on the crankshaft. He told me oil was leaking out of a hole on the front of the engine. Apparently he doesn't know how this engine is put together because if it was the crankshaft seal it would leak into the crankcase.

When I bought the sled it came with a gasket rebuild kit and all the parts I needed were in it including the rubber seal, metal washer and plate. I rebuilt the engine. Cleaned the carbs in an ultrasonic cleaner. changed all the o rings and changed the seals on the mag side at the stator. I used a 0.5 mm base gasket. I'm not too sure what else I can tell you.

So I got it all together, topped up fluids, bled the oil pump and mixed my gas 50:1 just to be safe. I put a couple of shots in with the primer and she started up. I drove it out of the garage and did a loop in my front yard and came back around to the back yard and parked it because it was late by this time. A couple of days later, it was -40'C, I put some more gas in it and started it up. I was going to go for a ride and see how it runs. About 1 minute after I left the headlight blew so I turned around and came back home. Just as I got it to the backyard it stopped. It would idle but I couldn't get it to go. When I would give it any throttle at all it would bog down and once I would release the throttle it would come back up to idle. In that little ride I went on was about 0.5 km.

So my question now is this: Is there anything I may have missed or not done properly to cause it to do this? This is the first 2 stroke I have ever assembled and the first snowmobile I have ever done any work to. My thoughts were that it might be a fuel issue, it bogs down because of lack of fuel and getting too much air when I press on the throttle. I could be totally wrong though. Maybe I have water in my gas? Froze up the fuel filter enough to prevent it from getting enough fuel to drive but not enough to prevent it from idling?

I was thinking of dragging it back into the garage to thaw out and add some iso to the gas and see if that helps.

Any and all info will be appreciated.
 

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I would check to see if you have water/ice in tank. Then I would pull the pump and take it apart and clean/inspect. As far as the headlight, it could be just a bulb or the voltage regulator. Does the tail light work?
 

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Discussion Starter · #6 ·
I actually don't have the key for the sled so it's unplugged behind the dash. I was going to pick up a new bulb after work tonight and try it out. I also ordered 2 6" led light bars, a rectifier and a small NiMH battery so I can run the light bars.

I'll check for ice in the tank. I also left the jerry can of gas I used outside to see if ice builds up in there, then I know I have water in that gas. So you guys think it sounds like a fuel supply issue? Anything else it can be that I can check in case my fuel supply is fine?

454ROTAX I had only thought of trying that when I was already in bed so I never did go back out and try that.
 

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The 97 did have a DESS. It will idle fine without it being plugged on but when you give it gas it will bog out.
 
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