63 Johnson 18 hp ignition mystery

[twocyclemania]

Started working on the 18 I picked up recently. It had the original (clear pinkish) coils that were disintegrated. I installed brand new coils and condensers and 'dressed' the points. I cut the ends of the ignition wires (both ends) for fresh connections. I had spark on both cylinders yesterday. I went out to finish everything today and I now have no spark. I disconnected the kill switch wires and re-connected them, re-cleaned the points and yet I have no ignition. I think the motor is possessed. Any suggestions? thanks

 

[F_R]

So, it had spark on both cylinders and it lost spark on both at the same time? About the only common item to both other than the kill switch is the flywheel key. Is it sheared? If it is, did you install it correctly? Shaft and flywheel tapers must be clean and dry and not buggered up. Nut MUST be torqued to 40-45 foot pounds. Failure to heed these instructions will result in sheared keys, and irreversible damage to the shaft and flywheel.

If it isn't a sheared key, 99% of no-spark problems are due to dirty/corroded/mal-adjusted points. It would have to be a coincidence to kill both at the same time though.

 

[nwcove]

F_R.....wouldnt the plugs still fire....but just at the wrong time if the key was sheared?

 

[HighTrim]

If the flywheel shifted just slightly yes, if moved too far, no.

 

[racerone]

With electonic ignition you get spark at the wrong time with a sheared key.------With points ignition the points will not be timed with the passing magnets and therefor no spark !!

 

[tomhath]

Even if the flywheel key isn't sheared you need to have it installed correctly to get proper timing. There should be a mark on it, that mark goes on the bottom when installed.

 

[twocyclemania]

Key is in place; I have the cylinder head off and the pistons are spinning as they should when you turn the flywheel. I'm going to go over the points and ignition wires again tomorrow. Yes, I am grounding the plugs as I spin the flywheel. Once something is up and operating you don't expect it to just stop for no apparent reason. This is the first time I've experienced something like this. Go figure!

 

[kbait]

Pull the armature plate and scrutinize the kill switch wires where they're clamped on - underneath the plate. A short at that location can be a bear to find..

Good luck!

 

[twocyclemania]

Went through everything over and over and still no spark; even tried 4 different plugs including brand new. I have no choice (as kbait recommended - thanks) to remove the mag plate and go over the kill switch wires. They look good on the top of the plate but I can't see underneath.

 

[Faztbullet]

I ran into a 40hp like this several years ago as it had been to several dealers and spark would come and go.After a lot of testing the bushing in armature plate would not ground to block and was simply fix by addinf a ground wire from plate to block.

 

[restornator]

How fast are spinning the flywheel?

 

[Chinewalker]

Make sure all primary wires are routed so they don't rub against the crankshaft or flywheel...

 

[twocyclemania]

I'm going to check out what Faztbullet recommended.I remember working on Corvairs years ago and when you removed the engine you had to be sure to reinstall the ground straps between the engine and body. Some never did and could not figure why it wouldn't start. As for the flywheel spinning - I'm spinning it by hand with the cylinder head off. I know what your thinking. I've done it a lot slower on other motors and still had spark. And as I noted, I had spark after replacing the electronics but it disappeared. I've got the primary wires tucked away and went over them again anyway. I'll get back when I try the ground wire unless anyone else has a suggestion. - I'll try anything! thanks everybody.

 

[Boat Doctor1]

Remove the flywheel- Look @ both coils-Cracked?? if so replace !! also points & cond. id highly suggest installing coils if needed?? with a coil locating ring too!! & points with a timing set fixture!! yet many today dont have these !! since its a 63 model with plugs out & cranked by hand (easy!!) & spark plugs grounded- should be fire @ plugs. If u cant see any spark?? just hold a plug in ur hand & have someone crank it!! Youll know for sure then!!!!!!!!!!!!!!!!!!

 

[racerone]

In post # 1 it is mentioned that this fine motor has new coils installed !!!!!!

 

[twocyclemania]

Thanks Boat Doc! I appreciate your input but as racerone noted I did install brand new coils and condensers. I like your 'hand' test and I usually try to convince one of the kids to help me with that one. This time I actually did it myself (over and over) and no spark. I'm going to try the added ground wire as recommended. I've worked on many a motor and this is a first for me.

 

[HighTrim]

I would try roping it over, or using the recoil.

 

[bwkre]

No Title

Twocycle, in your original post you stated that you "had spark yesterday" on both cylinders after replacing the coils, caps and dressing the points. Was this spark through spinning the flywheel or actually running the motor? I'm guessing it was by spinning the flywheel. It's such a simple system I'm sure your going to kick yourself in the butt when you find the problem.

Probably best to test with the recoil or pull rope. The voltage developed is directly proportional to the speed at which the magnet passes the coil laminations. ( to a point). You may not be able to move it fast enough by hand to produce a good high voltage to jump the gap of the spark plug.

I would remove the flywheel and see that the magnet is intact on the flywheel. ( I know, where could it go ) Does it have magnetism? Check the magneto cam that sits under the flywheel, is it locked in place with a key? is it still in one piece? If it is out of place ( timing ) or broken it won't operate the point correctly. If that's good I would put the nut on the crank and rotate the crank to confirm the cam moves and activates the points. I would use a meter or continuity tester across the points to "see" them open and close. Move clockwise only.

Then I would lightly set the flywheel on the crank. Rotate the crank to line up the timing marks. Two marks on the front side of the armature plate and one mark on the flywheel. Remove the flywheel and see that the cam is opening a set of points. Then slip the flywheel back on and rotate it 180 degrees. When you lift the flywheel the cam should be opening the other set of points. If the previous tests are good then it confirms that your points work and the timing is close enough to get spark.
If there is still no spark then it certainly could be a poor armature plate ground. Two bad capacitors or coils are unlikely. Did you replace the points or just dress the old ones?

Hope this helps.

 

[twocyclemania]

bwkre: I did turn the engine with the flywheel removed as the motor was originally stuck in gear (though you could put it in gear). I turned the prop and the cam (in place) opened and closed both sets of points. Points are set. I'm going to try your method as you described and pointed out in the photo. Since I'm just about out of options I'm going to try a ground wire. I'm also going to (never really thought to try it - thanks high trim) give it a rope pull and have the kids hold the plugs thanks!

 

[twocyclemania]

I gave high trim's suggestion with a rope pull. It turned over rapidly since I have the head removed (and a lot of oil in the cylinders). Still not a whimper of a spark. I'm going to try the suggested ground wire and as I've been able to determine it may be my last suggestion. This ignition problem is one for the books.