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Discussion Starter #21
I did some resistance checking over the weekend. I think it may be a bad plug cap. I have one on order. Once it arrives, I'll install and report back.
 

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Discussion Starter #22
I'm kinda at my wits end with this machine. I started it up yesterday. Still has a miss. Let it warm up..still missing. I'm wondering if it's the coil, but I don't want to toss money at the machine without knowing for sure.
 

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Discussion Starter #24
Now there's a thought! Will the coil from the 340 Puma be the same?
 

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Discussion Starter #25
Swapped over the coil and it's still running on one cylinder. It's the mag side cylinder that's not working. I pulled the plug boot on the mag side when running and no change in idle. I went to start it with the PTO disconnected and the mag hooked up; it won't start. Mag side is getting spark; it zapped me pretty good when I pulled it and the boot was making a pretty good snapping noise when it was resting on the metal engine cover; left a few marks from the spark too.

Compression is good on both cylinders; just under 115psi a side. I pulled the carb and intake manifold and no obstructions. Piston skirts on the intake side are OK.

Just to add to this; the sled will usually run fine once warmed up. So I'm kinda stumped as to what the cause is.
 

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I would lean toward bad compression. sub-115 psi would make it tough to start.
 

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Discussion Starter #28
Thanks guys! I want to say the Puma is about at the same for compression? I'll have to check next weekend.

KC,
I soaked the carb last near and even bough a new pilot jet. It was still running rough after that. I wouldn't be able to swap the carb because the Puma is a VM32, Jag is a VM34.
 

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If I wanted to be absolutely sure, I'd do a leak down test. Note that compression testers don't test which point it has compression, only the highest point. If it loses compression at 5 degrees before or after TDC and fires at 6 degrees, you might not be getting the 115 compression. To me, 115 is low anyway and I'd rebuild. 120 or higher is preferred.

My 340 tested at 136-136 just the other day. My 440 is testing at 145-145. (not bad for an all original parts 1982 machine!!) And yes, I've tested the testers (have two) they are accurate.
 

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Discussion Starter #30
Thanks Bear! And those are good numbers!

I’ll retest this weekend. I want to say the Jag usually tests at 120 psi cold. Odd that it would be lower warm.

A leak down isn’t a bad idea. An excuse to get a new tool.


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Idk I've had sleds at 110lbs of compression run perfectly fine for years without a rebuild. One sled that was/is still like that is my old '92 Indy 440 that someone local bought. Said it still runs like a champ and is still reading 110lbs of compression on it and has put another 1200 miles on it since I sold it to him 4 years ago and before that I had it for just under 5 years as a backup sled. It had around iirc 5500-6000 miles on it when I sold it. He said other then doing carb cleanings & a new set of graphite hyfax to replace the garbage plastic it has been a great sled for his teenage daughter.

Also agree with the leak down test, those are always good to have around!
 

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Be sure to test with throttle wide open and give it 10 good hard pulls!

Soaking a carb is good, but you have to spray the passages or it isn't clean!
 

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Discussion Starter #33
Thanks guys! For the heck of it, I may try to swap the Puma CDI over to the Jag and see if that helps.
 

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Discussion Starter #35
Well, I think it’s the darn TSS! I had an in-line plug tester hooked up to the sled when running. I jiggled the throttle at the pivot point, I could “see” the spark start missing and here the change with the engine sound.

The sled came with a different set of bars and a really sketchy setup for the heated grips. I got a set of oem bars off eBay and put those on. The bars have a three prong connector, the sled has a two prong. Thinking that may be the issue.

I’d like to take the two prong set up off the original bars and put that into the bars I have on the machine now. How can I do that without pulling the entire switch? Will the kill switch come off if I peel the sticker off and remove a screw hidden under there?








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Discussion Starter #36
Swapped everything over today....same problem.

The sled bogs, pops and doesn't ride all that well.

Now, when warmed up and I bypass the TSS, it runs normally. So I'm stumped here. I'm thinking of bypassing the TSS and installing a lanyard to prevent the sled from running away.
 

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Probably bad switch in the TSS system. There are two switches for it. They are connected in series and normally open when pressed. My 99 jag had the switch on the hinge go bad. I just disconnected it all and have a tether switch on it now.
 

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Discussion Starter #38
Thanks Bear. I'll probably go the same route. Thinking of using a two prong trailer wire as a way to bypass the TSS.
 

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On my 1999 Jag, it was just a matter of unplugging the cable. Normally Open to run. Just disconnect. No jumper needed.
 

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Discussion Starter #40
Thanks Bear! I think the older Cats ran a slightly different electrical system. When I unplug it, the sled stops running.
 
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