Likely sourse for insufficient spark?

[calm like a bomb]

I checked the spark and it will only jump 1/8" instead of the required 1/2"<br /><br /> Time to buy a powerpack or pickup coil?

 

[dolluper]

Re: Likely sourse for insufficient spark?

Check for bad grounds or just bad plug wire first

 

[JB]

Re: Likely sourse for insufficient spark?

Howdy CLAB.<br /><br />What engine are we talking about?

 

[calm like a bomb]

Re: Likely sourse for insufficient spark?

JB ,it is a 1987 70hp Johnson 3 cylinder.<br />I had 25 replys to the old post but it looks like everyone gave up on it.The post about the engine stopping suddenly after running fine all weekend.<br /> I finally determined that the spark would not jump the necessary 1/2" required.I only get about 1/8".<br /> Don't really know where to go next..timing,pickup coil or CDI box?

 

[Dhadley]

Re: Likely sourse for insufficient spark?

Did you check it with the boat harness disconnected?

 

[Basscat 1]

Re: Likely sourse for insufficient spark?

A fully charged marine battery with enough cranking amps. Also check the battery connections.

 

[calm like a bomb]

Re: Likely sourse for insufficient spark?

Dhadley,<br /> I am unsure what you mean about checking it with the boat harness disconnected.

 

[calm like a bomb]

Re: Likely sourse for insufficient spark?

Basscat 1,<br /><br /> This is not a battery problem.

 

[Basscat 1]

Re: Likely sourse for insufficient spark?

I read your " Engine quit suddenly after running perfectly " thread, and I dont think its a spark problem. If you are only getting a 1/8" spark, it might cause you an idle problem, but not a "not run at all problem."<br />Just my 2 cents.

 

[Dhadley]

Re: Likely sourse for insufficient spark?

There is a large red plug that connects the boat wiring harness to the engine wiring harness. Disconnect the plug and check spark again.

 

[Basscat 1]

Re: Likely sourse for insufficient spark?

Here is a post that might help. I would pay particular attention to what Joe Reeves says about proper cranking speed.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=029539#000018

 

[G DANE]

Re: Likely sourse for insufficient spark?

Read my last reply to your old thread and clean everything up. Take my advise and keep your thread for future - will give you more help. I dont think this is a crancking speed problem - then it should cranck reel slow. I guess you checked spark with all plugs out - right ? It will spin then.

 

[calm like a bomb]

Re: Likely sourse for insufficient spark?

Basscat 1,<br /> It's spinning like a banshee with a new fully charged marine battery.Plenty of cranking RPM..just no cranking.I'm gonna check the grounds again in the morning,then try it for the hundreth time and then probably drag to corpse to the dealer.I'm tired of screwing with it at this point.I appreciate everyones input.

 

[steviecops]

Re: Likely sourse for insufficient spark?

If you are sure it's a weak spark that's causing your problem, yoiu need to start trouble shooting the ignition system as per the manual. I had a 9.9 Johnson that had the same problem with a weak spark and I traced it to the charge coil under the flywheel. I had to invest in a DVA peak reading multi meter in order to do the trouble shooting, but it still worked out cheaper than taking it to a repair shop.<br /><br />There are some resistance tests that you can do with a basic ohmeter to give you an idea before you go spending money on an expensive tester. The tests are all in your manual.<br /><br />Good luck

 

[calm like a bomb]

Re: Likely sourse for insufficient spark?

Drug the corpse to the shop today..fish are biting and I have two other boats that run.Tired of beating my head against this one.I'll post the final verdict later....10 to 12 days waiting list.<br /> Thanks to all that helped.