JLO 440 Timing

[Toys4Me]

I replaced the points and condensers in my JLO and now I am having a hard time timing it. I am going by the service manual timing page but its very missleading. So far I have not had any luck and I'm trying to get it done in time for ashtabula. Looking for any kind of help/advice I can get. I have all the tools the instructions say just cant seem to get the dimming light thing.
thanks,
mike

[LarryW]

Oh crap, Looks like a Don or racerone3 question. Good luck! Hope you get it!

[LarryW]

I am pretty sure there doing some cdi conversion to get rid of the points? I have not idea really. I only know what I do and I have never done it. Just read it somewhere.

[Don]

If you've set the point gap to the spec in the book (.014" to .018"), you should see the light dim as you pass near the .083" to .102" BTDC. Disconnect the wire from the coil on the cylinder that you're timing (the one that comes from the stator plate and hooks to one side of the coil) and hook your light to that wire. The other wire from the light goes to engine ground. You have to have the advance weight blocked to the full advance position- I find a drill bit works fine if you don't have the special tool, just don't push it in too far or it'll tear stuff up when you turn the engine over.

You can change these over to CDI like Larry says, but the units are even harder to find than the ones for Chaparral.

Good Luck- see you in Ohio!

[Toys4Me]

Thank you Don. The instructions don't tell you to disconnect the coil lead just to clip onto it. Does anyone know where to find these cdi conversions? I called richards rip-offs and they don't know of any.

[hydromike]

I don't have a very comprehensive list of what came with the CDIs for the Rockwells, but a good place to start is to look for older liquid cooled cuyuna engines, which were found in WetJet jet skis, and some other applications. 2Si still manufactures these engines, (air and liquid cooled, I believe) and they can be found from time to time, but like Don says, they're rare.

Good luck!
~m

[Toys4Me]

OK still not having any luck. I just want to double check here when you say light what light are you refering to a test light or timing light?

[Don]

It's a powered test light that's used for static timing on a two-stroke (maybe four-strokes too?). Sorry- I thought that's what you were using. You're checking connection between the coil primary wire and ground. I don't have a light and I'm too cheap to buy one so I use an old lantern-type flashlight and put jumper wires between the engine block and the light bulb, and between the switch terminal on the light and the coil wire on the engine. When the flashlight switch is on, the light should light then get dimmer when the points open. I've tried the same thing with an ohmeter and it doesn't work.

[Toys4Me]

Turned out I wasn't using the right tester light. Went and picked one up (only 8 bucks) and still can't figure out this timing thing. Dad and I were both watching and turning and could not see any blink or dim. Now I'm just stumped and frustrated. Why cant this be like timing a car. Not sure what I'm doing wrong.

I'm gaping the points to spec.
Using a dial indicator to get the piston to TDC.
Hooking the (correct) continuity tester up and it lights up.
Turning the flywheel over slowly counterclockwise.
First just watching for a dim or blink or anything.( not seeing anything)

Does this at least sound close to correct steps?
thanks,
mike

[Don]

Sounds like you're doing it right. I don't know why you're not getting a dimming light. Are you sure you're on the right coil for the piston you've got the dial indicator on?

[Toys4Me]

We actually tried both cylinders. Is there anything I need to do with the key? We had it off.

[jerseybigfoot]

when you adjusted the point gap you can see when they are starting to open so you know you are close. if the battery operated continuity tester does not dim you need to add some additional resistance in the continuity loop. you can wire in an additional flash light bulb. I made a timing box from a small buzzer and 9v battery box from Radio Shack and that didn't work until i wired in a ten turn pot to fine tune the buzzer volume.

[jpswift1]

This might be a long shot, but on my JLO 400 (which is now a 440) I had an issue that could be similar to the symptoms you're describing. Hydromike and I were getting ready to fire my engine for the first time after I rebuilt it and it wasn't firing. We pulled the flywheel and it turned out that there was a crack on the cam advance mechanism or the timing hub I can't remember which) on the back side of the flywheel. Mike gave me a replacement one, we put it on, and it fired right up. Just figured I'd throw that out there. I never would have expected that, but he narrowed right down to that and sure enough, it was the issue. Pop the flywheel off and take a look.

http://cgi.ebay.com/ebaymotors/73-Scorpion-440-Snowmobile-434cc-JLO-Rockwell-Fly-Wheel-_W0QQcmdZViewItemQQhashZitem5ad5ae1497QQitemZ390132012183QQptZSnowmobileQ5fPartsQ5fAccessories

Snowmobile vintage JLO BOSCH ROCKWELL mag engine motor - eBay (item 400047679391 end time Jun-27-10 20:39:58 PDT)

[Toys4Me]

I've had the flywheel off I don't even know how many times and everything seemed fine. I really think I'm just doing something wrong. Going to try adding some more flashlight bulbs and see if I can get that light to dim. I'm just starting to run out of time and patience.

[Don]

As a last resort, you can always bring it to Ashtabula as it is and before you know it, you'll have a dozen heads under the hood trying to figure it out.