Diagnosis???

[lawdog]

I have limited information here, but I have a guess and want others to confirm. My dad owns two '89 (approximately) Jag AFS snowmobiles that the grandkids ride at their house. My nephew called and said that one of the sleds runs for a little bit, loses power then dies. Let it sit and it starts back up and runs a little while and does the same thing. I haven't checked it out yet to see for myself what is going on, but given his description, I'm thinking electrical. Any thoughts???

Thanks.

[fishersofmen]

Something to do with the fuel. I think if it was electric it would do it all the time....

[Mr. Nailz]

I would guess you need to clean the carb. They get gummed up and will act like that.

[ChuckN]

At least it's an easy sled to work on...

Check for spark after it dies.

I would also say fuel related, almost like it's running out of fuel. I would look at the fuel pump to see if it's pumping fuel. Also, I've seen the (vacuum) air hose from the engine to the fuel pump rot on these vintage sleds and there's an air leak that effects fuel pump performance.

Possibly needle/seat in the carb have worn out and the carb needs some attention.

[PierBridge]

I wouldn't run it anymore it sounds like its leaning out which is cuasing Cyllinder and Piston damage.

[ishgood]

Ive seen this behavior caused by plugged fuel lines. If there is a pickup screen in the tank that screen could be plugged. Could be kink in a line or plugged filter or a restriction anywhere. You'd think they would just not run at all but after sitting for while enough gas will seep thru the clog to fill the carb and then you can drive a little ways.

I ran into this on a '71 Evinrude Bobcat. It was nightmare. Used to act up 10 miles down the trail. Finally got mad enough to tear everything apart and I found a brass sceen BEHIND the fuel fitting on the carb. It was plugged with plastic shavings that were probably in the fuel tank from the factory.

Sleds. Gotta love em.

[lawdog]

Interesting, I was thinking heat related problems with the electrical system. Carb would be easy. Clog in the gas tank not so easy, but thinking its a good possibility...

[norm]

I'm with you Lawdog. Sounds like an electrical problem. Once you get the thing to die, check for spark right away. That way you'll know if you're having electrical or fuel related issues.

[Longline]

Check to see if there is a inline fuel filter. For a couple bucks that would be a cheap test.

[lawdog]

I replaced the fuel filters and put a kit in the fuel pumps last year (two identical sleds he has...). I haven't had time to go up and check this out either, but I'll try to check it out this weekend and get back to everybody.

[Dozer]

When I was a kid I had a 79 ski-doo everest. One winter my old man went on a bussiness trip for a week, the first day he left the everest started acting up. It would run just fine for about 15 or 20 min then die. If you let it sit for 15-20 min it would start back up and run fine for anouther 15-20 min. I was like 10 years old so I didnt know any better so we rode it like that all week till he came home. He found that the fan belt was broke. It would run till it got hot then lock up, after it would cool it would free up and off we would go! Wound up with a rebuilt topend and a red a** out of the deal!