MY13 Pro 800 down 1 cylinder.

[ken.gee]

I had to use my 2013 Pro 800 on an ice fishing trip recently and ran into an issue. It was -35 when we started the 29km trek to our spot. At 16km we stopped to warm up...and the sled cooled down quite quickly. -35 without the windchill isn't an ideal time to go ice fishing (can't say it's the brightest thing I've ever done), and I found that the sled didn't warm up very quickly at idle either. Unfortunately we had to start moving again and the sled wasn't fully warmed. Within 30 seconds of taking off I noticed that she was only running on 1 cylinder. Once the engine temperature climbed to 53c and stayed there for a minute, the other cylinder fired and it began to run normally. That same situation happened both on the return leg, and offloading at home (though I was able to properly warm the machine both times).

I'll take pictures of the plugs when I get home...but didn't think they would be the primary cause (based on my assumption that a fouled plug wouldn't fire back up).

The engine is stock, and plugs only have a couple of trips on them. The only factors that I can imagine would have contributed would be the cold, prolonged idling, low elevation, and slow speed we were travelling (15-20 km/h).

Any ideas would be greatly appreciated!

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[TDR]

My pro does not like to be moved when cold. It will foul the plugs unless it is up to near normal operating temp

 

[JMCX]

Do a compression test. If that's normal pull the plugs the next time it acts up. Whether the misfiring cylinder has a wet or dry plug should help narrow things down.

 

[CUSO]

Can things ice up somewhere when very cold?

Perhaps the thermostat is stuck open..

 

[gdhillon]

Noob question, how do you know its running on only one cylinder?

Besides lack of power does it idle erratically?

 

[ken.gee]

Noob question, how do you know its running on only one cylinder?

Besides lack of power does it idle erratically?

It doesn't idle erratically, but it doesn't have the normal rumble. It sounds like my 600 trail used to. It's also very slow and not as crisp as I'm used to. You can hear/feel when it drops and picks up a cylinder.

Easiest way to check when it's warm is to put your hand on the head where the plugs screw in. One side is room temperature while the other is hot.

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[ken.gee]

Sled also went down on 1 cylinder yesterday, 5 seconds after starting it.

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[Beels]

I'd put new plugs in it and try that. Doesn't take much to foul them.

 

[neilsleder]

I can't see from the pictures but if those are champion plugs, throw them in the bush! Then go buy NGK plugs. Both plugs are looking rich!


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[TDR]

Clean the air box side of the throttle bodies and install NGK's. The gap between the butterfly and the body gets dirty which in turn restricts air at idle hence the reason for the fouled plugs. The air box is not pleasant to remove but you need access. I would undo the fuel lines at the top of the tank to give more wiggle room. The Champions are definitely junk from my experience.


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[ken.gee]

Do a compression test. If that's normal pull the plugs the next time it acts up. Whether the misfiring cylinder has a wet or dry plug should help narrow things down.

Thank you for your reply! Did a compression test...111-112 PSI on PTO side, 115 Mag. Not sure if it's normal for them to be off like that? Repeated the test twice, same results. PTO side was the side to go down.

Clean the air box side of the throttle bodies and install NGK's. The gap between the butterfly and the body gets dirty which in turn restricts air at idle hence the reason for the fouled plugs. The air box is not pleasant to remove but you need access. I would undo the fuel lines at the top of the tank to give more wiggle room. The Champions are definitely junk from my experience.

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Thank you for your reply! I'm using the NGK BPR9ES plugs. I'll definitely do this clean this summer...just wondering if the fact that I had the sled idling for so long, moving so slowly, and at essentially less than 700ft above sea level would make a difference? I'll definitely swap the plugs out now and see what happens.

 

[Beels]

How many miles are on it?

 

[ken.gee]

How many miles are on it?

1416km (880mi)

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