Johnson 35HP ('78) No spark on top cylinder

[TerryMSU]

I had a cranking issue that is now mostly fixed. Well now I got a different problem. My top cylinder suddenly has no spark. I swapped the coils and the problem did not follow the coil. In the process of re-routing the starter cableing, I pulled on the harness that goes to the ignition. Is there any way that I could have stopped only one coil by damaging the harness between the ignition switch and the motor? If not, are there any other ideas that I should try? (I know, get a manual! Working on it. What is the cheapest way to get a manual?)

I did use a spark tester, and the bottom spark is good and strong, the top one is non-existent even with a small gap set in the tester.

Thanks,
TerryMSU

 

[HighTrim]

Re: Johnson 38HP ('78) No spark on top cylinder

Re: Johnson 38HP ('78) No spark on top cylinder

Either a faulty power pack or ignition coil normally cause this. Extremely rare causes include a weak trigger magnet in the flywheel or a timer base. Try ebay for an original manual, well worth the money.

 

[TerryMSU]

Re: Johnson 38HP ('78) No spark on top cylinder

Re: Johnson 38HP ('78) No spark on top cylinder

Not coil, swaped orange wires (primary on coils[?]). Got good spark. By the way, the motor does run on just the good spark/cylinder.

Exactly, what does the power-pack do? (Is it the same as the CDI?) Is there an easy test? A good digital multi-meter is about all I have for special test equip.

Checked E-bay, etc. how do I tell the original? Listings there for CD version, SELOC, etc. I know that SELOC is not preferred. What about others?

Thanks for the help,
TerryMSU

 

[TerryMSU]

Re: Johnson 38HP ('78) No spark on top cylinder

Re: Johnson 38HP ('78) No spark on top cylinder

bump

 

[TerryMSU]

Re: Johnson 38HP ('78) No spark on top cylinder

Re: Johnson 38HP ('78) No spark on top cylinder

bump

 

[HighTrim]

Re: Johnson 38HP ('78) No spark on top cylinder

Re: Johnson 38HP ('78) No spark on top cylinder

definately keep an eye open for an original manual, usually rough shape for that year, but I find them a million times better, the are usually listed as original manual. You can check the diodes in the power pack with an ohmmeter.

 

[TerryMSU]

Re: Johnson 35HP ('78) No spark on top cylinder

Thanks HighTrim..

I am getting ready to put a powerpack in it. Will I need to reset the timing or anything else or will all the adjustments be the same? I don't have a timing light, but could borrow one if it is necessary. I still have not gotten the official manual, but I borrowed a SELOC manual from the library and it appears fairly clearly written. I also have a Clymer manual on hold at the library, but it is not due for a couple of weeks.

By the way, any comment on brands etc on the powerpack. I am getting a used OEM (Johnson) powerpack (30 day warantee). For about $25 I could get a non-OEM pack that is new.

Thanks,
TerryMSU

 

[iwombat]

Re: Johnson 35HP ('78) No spark on top cylinder

Just for giggles.

You say you may have tugged on some wires. It could very well be you pulled a connector out of its seat. Between the powerpack and the stator there's a big rubber barrel connector. Take it apart and make sure all the connectors are seated to the proper depth. Then, go ahead and clean up all the grounds on your powerpack before your purchase.

Money is still on the powerpack, but sometimes you gotta check the basics.

 

[HighTrim]

Re: Johnson 35HP ('78) No spark on top cylinder

I have only got OEM power packs, so sorry I cant comment on the aftermarket other than to say I wouldnt get one, not to say they are no good because like i said, I have no experience in them. Just refer to the diagrams provided when reconnecting the magneto CD ignition system leads to the power pack. Ignition coil and sensor coil sequence must be observed. All high tension leads must be kept separated. Check ground leads attached for good ground.

 

[iwombat]

Re: Johnson 35HP ('78) No spark on top cylinder

I've used the CDI power packs. No issues to report.