9/74 J600D technical knowledge request

[AHenry014]

Sled build date 9/74
Machine SN 030616M
Kioritz CCW engine

I recently acquired a non-running JD 600 from a friend of mine that hasn't run in a number of years. It is in quite good shape, has a mountain of compression, and just about 500 miles on the odometer. This is certainly not my first rodeo with small engines, 2 strokes, etc. but will admit that this machine is my first real experience with snowmobiles. I got the plastics removed for ease of inspection/maintenance and got to taking a look. There are a couple things to take care of right off the bat; the impulse line to the fuel pump is disconnected at the engine (that looks fun to reconnect), all the fuel lines need replaced, and it has no spark. I finally found a suitable wiring diagram today, so I will use it as reference when I dig into the spark issue. From my experience with tractors, lack of spark is either the ignition switch (I need to finish diag with my new wiring diagram) or the points. I assume they reside under the pull start/flywheel, but have yet to confirm.
Here is my list of questions:

Points --> Is the flywheel under the pull start? If different than a harmonic balancer pulley, what puller do I need for the flywheel? What is the points gap?

Carb --> I haven't had a chance to inspect the carb for model/PN, but hoping to procure a rebuild/gasket kit for when I do need it. What kit do I need? I usually ruin bowl gaskets when disassembling these old carbs, so I assume Ill need a replacement for that. I found the base settings in the owners manual so I will use those as a starting point.

Fuel/oil ratio --> I have read that I should run ONLY 93 octane, which is fine, but want to ensure i mix the fuel correctly. I have modern 2 stroke outboard oil that i plan to use. 40:1 was my jetski go to and I have read that it might be accurate for this sled.

Spark plugs --> NGK B7HS is what it came with and is the PN for the replacements I bought for it. Just want to verify they are correct. Looks like 0.020" gap is listed in the owners manual.

Drive chain oil and level --> I found the owners manual pdf online but want to ensure I do this correctly. I plan to suck out what's in there and replace it. Manual looks to call for SAE 30 oil between 1/4 and 1/2 inch below the edge of the inspection hole. Is that correct?

I think that's all I have for now. I am chomping at the bit for the first real snow to happen in CT this year and really would like for this thing to be working!

[AirborneX4Special]

Congrats and welcome to the insanity of old John Deere snowmobiles! Your sled is a 1975 model if the 9/74 figure is the build date from the tunnel.

First off, change the crank seals. Any sled that has been sitting for more than a couple years will need them. Next, clean that carb. Ultrasonic cleaner works best if you have access to one and it may require several laps through the cleaner to get it squeaky clean. Higher octane gas is better but avoid ethanol if at all possible because it dries out all the seals and causes all manner of issues. Deere put a mixture decal on the fuel tank bracket next to the cap and if memory serves it recommended 50:1 with Deere oil and 40:1 with others so they could sell more product. Spark plugs are cheaper than pistons and jugs so running rich is sometimes a matter of convenience. Chain case oil is up to the owner to some degree. Deere recommended gear lube in their later sleds but running 15-40 motor oil works fine, especially in colder temps. I can't remember which puller you need but someone else will know. New Breed parts or Don at Busco Bullet will have the stuff you need and a replacement ignition system from Hewtech is a more reliable choice than the OEM system. I think the carb is a Bendix but again I don't recall. How's your track look?

[Cdnturboz]

Welcome - good place to start is this website:

https://vintagesnow.com/John_Deere.html

That should have your service manual for your sled. That should help you identify which carb etc you have as well as repair procedures.

If yours is a 74 (you would have to verify) but your sled may have a Bendix Carb (rebuild parts are quite hard to find/no longer exist)

Points would be under the flywheel - you would need a sled flywheel puller from a company like Kimpex etc


Just my opinion/ experience if you do some reading most of the veterans on here say to immediately change crank seals when you get the sled. DO IT, I picked up a 74 400 which is similar that had been sitting, got it running good (cleaned carbs new plugs etc) but never touched the seals/didn’t follow their advice - by the end of the third ride I had destroyed pistons. These motors are old and the crank seals dry out.

[AHenry014]

Thank you both for your input! I did read a thread or two with the same recommendation, to replace the crank seals. How deep into the engine are we talking? From my quick peek around, it appears to be the seals on the outboard side of the crank, so right behind the flyhweel/stator/points stuff and opposite on the PTO side. Anyone point me to the part numbers on them? I thought I came across them for something like 4 bucks a piece but cant seem to find the listing now.

Took a quick look at the track last night, looks quite good!

[Cdnturboz]

If you go to: https://newbreedparts.com/collections/gasket-sets they should have the seals/gaskets. I "think" you can do the seals without splitting the crankcase, but a lot of people split the cases and inspect, etc. (that service manual link I sent has the procedure to do it I believe without splitting)

[AHenry014]

Great, thank you.

[AHenry014]

Well, it runs. Got the pull start and pulley removed to inspect the points. Everything under the pull start is still gold (zinc plated) and spotless. The points werent corroded, but I gave them a couple passes with a points file, then regapped to spec. Got it back together and found spark on the right cylinder, but not the left. At some point in this machines history, someone replaced the left cylinders coil and reused the spark plug wire. The wire pulled right out of the coil, so I assumed it wasnt making a good connection. A quick trim of both ends and we were in business. I replaced the plugs with the correct ones for the machine, NGK BR9ES (regapped to spec), over the B7HS's that were in it. It fired up briefly on a shot of fogging oil, so we have a runner!

Next up, the fuel system. The carb is a Bendix unit with a separate, Walbro Autopulse, fuel pump. The fuel pump appeared to have been zip tied next to the intake silencer, but I dont think thats the correct location. Does anyone have a photo or link to where this pump should be? Found a rebuild kit for the pump and also some plastic variation replacements. I am going to give this pump a shot and if it survived its slumber. As for the carb, I got the bowl off and everything appeared to be very clean, but I did find a homeade bowl gasket, so that will need to be replaced. Research shows that older harleys used these Zenith Bendix carbs, with the additional feature of an accelerator pump. The kits are cheap on amazon, but I want to confirm I am getting the correct kit. Can someone confirm the pump location and carb kit I need?

[Cdnturboz]

I can take a photo of mine tonight - that bendix Harley kit I’ve heard of but never tried it myself.

[AHenry014]

No worries if you dont get around to it. I actually ordered a mikuni style pump since it face mounts, should be easier to plumb that and ensure i have a good pump (Ill order an actual mikuni if it proves to be questionable, but the legit pump was over a week out, so a knockoff it is). I did order the harley kit and will report back with any issues. It does look like it will work looking at the kit and the carb.

[Cdnturboz]

Yeah I think that's what I did while i was waiting for my bendix style fuel pump rebuild kit to arrive. I ended up just leaving the mikuni one on (mounted it to the same hole on the aluminum shield that the stock pump mounts to)

Interested in how that carb kit works (when I rebuilt mine I was fortunate enough to source a kit that a gentlemen used to make - I believe he doesn't make them anymore or has passed away)

[400brian]

Sorry I saw this post late.

Go here for a quick guide : [http://jdsleds.com/jdsleds/forums/viewtopic.php?t=162][/url]

I assume the sled has a Comet C-100 clutch on it. You will need a Comet Puller to remove it. New Breed parts or Busco Bullet should have one.

I covered a fair amount of what you will be doing here; http://jdsleds.com/jdsleds/forums/viewtopic.php?t=17177

[AHenry014]

Thank you sir, thats a big help! Yes, I do have the comet clutch. I havent had time to get back to this sled, but first plan to get the carb cleaned up, the new fuel pump in place, and new fuel lines. We will see where I stand at that point.