crank seals

[nytrodude]

My brother has a John Deere Trailfire 440. Single carb, twin cylinder. The last few years it has a idle problem- it won't unless you give it throttle or turn up the idle to the point of clutch engagement. I personally have not looked at it. He replaced carb boot last year- didn't help. He cleaned carb this year- didn't help. He bought a new carb now- still the same. I was wondering if a leaking crank seal could cause this. I was thinking a leaking seal would cause the engine to idle fast--YES/NO?

 

[trailshredder]

With sled running spray carb cleaner around seals, base gaskets and carb boots. If the sled starts choking out.....you found a problem.

 

[indy_500]

crank seal would definatly cause this problem, like trailshredder said, spray carb cleaner around all seals/gaskets to look for leaks

 

[dschultz]

Exactly what they said, we have done a few seal replacements on them around our place. 99 percent of the time the problem is the center o ring seal goes out it these. It is like a 2 dollar part that will make these sleds junk. If you end up replacing the seal use a pot of boiling water and place the o-ring in it for a few min. and then you can stretch it over your crank.

 

[polarisrider1]

My brother has a John Deere Trailfire 440. Single carb, twin cylinder. The last few years it has a idle problem- it won't unless you give it throttle or turn up the idle to the point of clutch engagement. I personally have not looked at it. He replaced carb boot last year- didn't help. He cleaned carb this year- didn't help. He bought a new carb now- still the same. I was wondering if a leaking crank seal could cause this. I was thinking a leaking seal would cause the engine to idle fast--YES/NO?

I know a guy in Grand Rapids (not far from you) who has crank seals for that sled. email me if you need a phone #.

 

[nytrodude]

Exactly what they said, we have done a few seal replacements on them around our place. 99 percent of the time the problem is the center o ring seal goes out it these. It is like a 2 dollar part that will make these sleds junk. If you end up replacing the seal use a pot of boiling water and place the o-ring in it for a few min. and then you can stretch it over your crank.

Is there any way to diagnose if the center seal is leaking?

 

[dschultz]

Is there any way to diagnose if the center seal is leaking?

best way is to use starting fluid or carb cleaner and spray at the pto side seal while the engine is running. If the engine speeds up then your seals are bad. Not really a way to check the center one but you could bet the farm that they are all bad. This was a piss poor design by jd and one of the biggest reasons you would find so many of these sleds sitting. Once you fix the seals and rering it, it will be a strong running machine.

 

[trailshredder]

best way is to use starting fluid or carb cleaner and spray at the pto side seal while the engine is running. If the engine speeds up then your seals are bad. Not really a way to check the center one but you could bet the farm that they are all bad. This was a piss poor design by jd and one of the biggest reasons you would find so many of these sleds sitting. Once you fix the seals and rering it, it will be a strong running machine.

I agree...also no way to check mag side seal either. My parts books still show seals for this sled so parts should be readily available.

 

[nytrodude]

Thank you all for the input. I may get a chance to look at it myself this weekend. I will post an update.

 

[indy_500]

You can take your recoil off and start it by wrapping a rope around the clutch and spray on the mag side.

 

[polarisrider1]

No real decent way to check center seals. engine will stumble because of uneven crankcase presure. I do have a 340 Trail fire motor for sale you can bolt right in. runs fine, I can bench start it for you. email me if interested. Not far from you. M6 and M50. http://cgi.ebay.com/ebaymotors/JOHN...93113313QQptZSnowmobileQ5fPartsQ5fAccessories