1969 Chrysler 9.9 no spark on one cylinder

[DonegalDave]

Hello to all, greetings from Ireland and thank you in advance for your help.

I restored this outboard that was an auxiliary engine so has done little work. It was running well then next time I ran it it only ran on one cylinder. My gut says it is probably the coil but I need some technical info to find out for sure.

Sorry if this has been answered before, there are lots of posts on 35+ hp engines and more modern ones. I don't know if the specs are transferable.

I swapped the plugs and it is still the top cylinder that fails. No spark at all. Bottom cylinder has an excellent big blue spark.

Could it be a capacitor?

Just a note, the woodruff key for the flywheel is very slightly sheared. Would running it on one cylinder for an hour or so have caused this? (yeah, I know!)

The engine serial number is 917 1348

I have a standard multi meter reading ohms and continuity etc. not a full ignition tester

These are my questions:

1. Are there specific readings for resistance through the coils? The primary shows zero resistance, what should the secondary read?

2. Can I test a capacitor with a standard multi meter? If, what are the readings required.

3. The manual says set the points at 0.20 when the cam for the points is approx 10 degrees past the top of the cam. Although this actually worked very well it seems a very rough way of getting them spot on and equal. Is there a timing point for static timing BTDC? I assume it must be 30 degrees but is it?

Thank you again,

David

 

[Nordin]

The coils should read 0,5-1,5 Ohm at prime side and 5,5-8,0 kOhm at secondary side.
You set the gap at top on camloob and yes 020 in.
The points should open 180 dgr from each other. measure with your multimeter (resistance) over one points and note with a pencil when it opens.
Turn the flywheel about 180 dgr and measure over the other points it should open at the pencilmark at camloob.
You have to disconnect the capacitor to do this.

You can check a capacitor if it charge if you have a analog multimeter but you do not know if the value is right.
Put the leadtips at the wire and the capacitor housing to charge it. Then reverse the leadtips and note if the needle jump for a short while.

 

[wickware]

1. Have you dressed, cleaned and checked the point?s contacts for continuity with your ohmmeter?
2. Have you switched condensers with coils to see if the fire change coils?
3. With a working set, I feel trial and error or your meter should find the problem.

Good Luck!

 

[S.A. Baker]

If you are reading zero resistance in the primary side of the coil ... I'd say the primary side has an open....bad coil!

 

[DonegalDave]

Thank you all for your input. This is what I did:

I took the capacitors and points off to check and clean everything and I redressed the points. The coils visually look good, but they are nearly 50 years old.
I did the static timing and on the second set of points the bolt holding all the positive sides together was in poor shape and reading a resistance of 20 ohms when the points were closed. So I sorted that. Set the gap to 0.20 on the first set and statically timed it to 30 degrees BTDC. The second set I set to 0.20 and it was bang on 30 degrees BTDC. So I was happy with my feeler gauge skills. (I have to get my thrills from somewhere!)
So I put it all back together and there is a good spark on both plugs. Note, the bad earth / connectivity was on the bottom cylinder points and the misfire was on the top so I am blaming pitted points or an undiscovered bad connection.

I am in Ireland and parts are unavailable. I have a son -in -law coming over from Seattle so I might get him to bring new parts. Carriage is prohibitive on such an old engine. I am happy that $50 of parts sit on the shelf 'just in case'.