1979 115 hp no spark on three of four cylinders

After running about four miles out and trolling for about 45 min. the engine died like someone shot it in the brain. Would not restart so after several attempts I started my kicker and trolled for about an hour. Then I tried to restart the 115 and it started right up. But it only ran for about ten min. and again died. This time at about 3000 rpm but the same hard die, no sputter, no slowing just died. After I got home I tried to start it again on the muffs but no go. Removed spark plugs and hooked up spark tester set at 7/16 at first I got a good spark on #1 but all others were dead. After a few attemps the spark on #1 cut out entirely. I removed fly wheel checked key and did a visual on stator and it looks ok. I'm just looking for some more simple things to check before I start testing electrical parts. It seems to me it must be the stator or trigger assembly. Any ideas would be great!
Thanks
Sherm

Re: 1979 115 hp no spark on three of four cylinders

1. Disconnect the black/yellow stop wire and retest. If the engine's ignition has spark, the stop circuit has a fault-possibly the key switch, harness or shift switch.
2. Disconnect the yellow wires from the rectifier and retest. If the engine has spark, replace the rectifier.
3. Check the stator and trigger resistance and DVA output as given below for both banks:

Wire Color: Check to Wire Color: Resistance: DVA Reading

Brown wire: Brown/Yellow wire: 450-550: 150V or more Connected
White wire :Blue wire :38-42 :0.6V or more Connected
White wire: Green wire :38-42: 0.6V or more Connected

4. Check the cranking RPM. A cranking speed of less than 250-RPM will not allow the system to fire properly.
5. Check the center hub triggering magnet in the flywheel for damage and tight fit.

Re: 1979 115 hp no spark on three of four cylinders

Powerpack.

Re: 1979 115 hp no spark on three of four cylinders

1730V said:

Powerpack.

Click to expand...

i believe that engine has two powerpacks, i have never seen one, (myself) drop spark on all but one cyl. , i would say do as high trim stated, and i am going to say the stator/charge coil ring is bad.
SERVICE MANUAL= best investment

Re: 1979 115 hp no spark on three of four cylinders

Can't disagree with getting a manual and going through the checks.

If the engine is putting out volts, on the charging circuit, the stator is probably OK.

I don't like throwing parts either but my experience tells me that dropping cyl's says powerpack.

The manuals spell this diagnostic tree, very well.

Re: 1979 115 hp no spark on three of four cylinders

Thanks for all the input. I have the manual and a regular meter but I don't think it will help in checking the stator output. Do I need to buy another meter and what should I buy. Sorry I seem in such a hurry but salmon season closes on the 7th.
Sherm

Re: 1979 115 hp no spark on three of four cylinders

no you don't have to buy a new meter...just buy a DVA adaptor...do a search on google for it and you'll find one...I think CDI makes one of the best ones...copy and paste this link and it'll take you to the unit.


http://www.marineengine.com/products/accessory.php?in=1329773


Thats a decent price I found one on ebay a bit cheaper...the DVA is a must though from what I've learned

Re: 1979 115 hp no spark on three of four cylinders

Oh good. I disconnected the black/yellow wire form the key switch and sure enough I now have spark. I will check switch and for a ground in that wire. I'll also get one of those adaptors for my meter. Thanks for the help guys.
Sherm

Re: 1979 115 hp no spark on three of four cylinders

Check the ignition switch first. If you have a emergency kill switch, make sure it is working properly too.

Re: 1979 115 hp no spark on three of four cylinders

Yep it was the key switch. I had an old one in the garage that I installed and it worked fine. The key switch I removed was only about a year old. Go figure. I cut apart the old switch just to see what happened. What a poor design. The interior post are surrounded by a copper ring that is only about 10 thousands away. A little corrosion had formed between the ring and the post in just the right places to shut down the engine. Any one know of a quality switch maker as I think this was a oem switch.
Sherm

Re: 1979 115 hp no spark on three of four cylinders

good job