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Discussion Starter #1
I'm putting a copy of this on AMSNOW also

Friday Morning in Newberry. Our sleds sat outside of our trailer as we had unloaded them when we arrived late at Newberry. We had covers on them and the sleds were chained up. The temperature outside was 5 degrees. Both gas tanks had about 5 or 6 gallons of gas in them.

We get out and start the firecats. Mine runs for about 20 seconds and dies. My friends F7 Sno-Pro runs about 2 minutes and I turn it off when I discover the first one isn't running. I want to hear what the first one sounds like when I start it up again, so I turned off the Sno-Pro. The first sled won't start. Then, when I start the Sno-Pro it will not run right either. It runs roughly and won't stay running.

Okay first thing I do is pull the plugs on my standard F7: I have about 540 miles on it and it ran awesome last weekend. The plugs are the original from the factory. I look at the plugs they look fouled. The plugs are wet with gas. I put two new plugs in the sled. It won't fire. Remove the plugs, check them for spark. They are sparking. Dry them off. Try to start the engine. It will not start at all.

The first pull on the engine is harder than subsequent pulls. The first time I try to pull it, it's feels normal. Subsequent pulls are about 10 to 20% easier. . .hmm. . . is it compression, or fuel going into the cylinder with oil causing lubrication for the second pull, etc. Maybe I'm analysing the sled to much.

So now our thoughts turn to BAD GAS. Could it be condensation or bad gas? We go buy a can of dry gas and put half of it into each tank shake the sleds a bit to mix the dry gas, go to McDonalds and eat breakfast and come back 40 minutes later. Try to start the sleds, mine won't start at all. My friends Sno-Pro F7 runs rough.

So now we figure it's time to replace the gas in one of the sleds and see if that will help it. We drive out buy a couple of 5.8 gallon gas cans and return and syphon the gas out of my friends Sno-Pro F7. We use the second can we purchased to haul gas from the local Pickelman's AC Mobile dealer to the sled. 5 fresh gallons and we run his sled for 3 minutes. It still will not run correctly. Okay maybe it's something frozen. We flick the levers of the sleds a few times to see if it's the emergency cutoff switch (without the sleds running). We then start up his sled, but cannot get mine to start.

We fire up the heater in the trailer. We heat our enclosed trailer up to 70 degrees (yes we have a furnace in our trailer, but don't normally heat it up with sleds in it.) We pull the Sno-Pro into the trailer and let it sit in the heated trailer for about 40 minutes. We raise the hood of the F7 Sno-Pro and place the hot 4 inch heater vents right into the engine compartment to heat the engine and components up a bit. We start the sled, it runs rough. It barely will stay idling and acts like it's running on maybe one cylinder and perhaps missing on the other. We put new plugs in it, but that didn't seem to help either.

One weekend trip to Newberry from Detroit area. Miliage = about 800 miles on truck to get there. Total miliage on the sleds this weekend = ZERO. Two dead sleds delivered to an AC dealer for diagnosis.

We've spent more time preparing this sled for the season than any other sled we've owned. We've put alot of TLC into both sleds, studding, iso vibe riser bars, skid plates, etc. Burped the sleds with our own mar-lift. We have never seen the fluid level drop. My sled overheated twice and went into fail safe mode two weeks ago when the sno-flap was sucked into it during a ride. I put about 150 miles on the sled since then with no problems and didn't run the sled very long when it did overheat.

Will post more when we find out what the dealer's mechanic will say.

I'm wondering what you guys think this could be:

I'm hoping that perhaps water or ice was caught in the fuel rails and the sleds will be fixed with some kind of injector fuel rail maintainance by the dealer. We did confirm spark in my sled which wasn't firing.

I smelled the spark plug of the sleds after we put in the dry gas and on one of the plugs there was more of a dry gas smell than gas.

We also pulled the exhaust pipe off the Sno-pro to inspect the pistons. The pistons looked mint. Clean without scuffs or any noticable wear. Looks like the motors were broke in right. (We did follow motor break in procedures per AC recommendations.)

Opinions.
 

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I saw two F7's in Bruce Crossing have similar problems. Both sleds were on their maiden voyage. One refused to start. The other sputtered around the parking area behind the grocery store. It sounded terrible. Appeared to be a fuel delivery problem. Eventually the owners loaded the sleds up for a lift to the local cat dealer. When I first read you post I thought you were one of the guys. Newberry though.
 

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Discussion Starter #5
Reply to smart valve question.

Yes we did.

One of the smart valves was closed. However the mechanic I talked to said at times one of them might be closed and the fuel could be pulled in by the other one.

It's difficult to say if perhaps both of them were closed when the sled didn't run. The fresh plugs I put in, when it wasn't running were getting wet with fuel.

The sales guy at my dealer said, "the sled is running" last night. I guess they got it running. Not sure if any other issues came up. The thing ran after being in the warm service garage. They are leting it sit in the cold and will try starting it cold.

Gene's sled (one of the two that didn't start) wouldn't start because of an throttle cable problem that he created. Seems that the cable was either routed wrong or wasn't snapped in fully. His runs now. Mine should be set soon.
 

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Discussion Starter #6
Conclusion:

Last dealer that saw it said it was "flooded". We tried to start is several times and one of the smart valves were closed. It's difficult to say if it was flooded or if Ice in the line or a frozen smart valve was involved. Dry gas was in the sled when the dealer started it after having it sit and warm up in the garage overnight. The sled started in the cold also and has started since. I replaced the gas (just in case it's bad) and haven't had a problem since.

The problem?, whatever it was is now solved. It could be that the sled somehow flooded originally because of a fouled plug. The dealer mechanic said I could "hold open the throttle" fully while starting it and the fuel pump would "shut down" and the added air going into the cylinder would cause the rich mixture to be pulled out of the engine. Allowing it to start. (I put a post about this on AMSNOW, to get AC's response about this suggestion. . . because the manual says, "don't start it with your hand on the throttle, etc.")

AND THIS REPLY FROM AMSNOW

sportrac54 on 1/27/2003 11:43:00 AM
The Cat was here...

The mechanic is correct, when flooded apply full throttle, no fuel will be injected .
This practice applies to most EFI systems being a snowmobile or a car . Check out
the car owner's manual under what to do if engine is flooded .
The injectors are off at full throttle if a specified rpm is not reached.
 
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