1988 Johnson 30 hp only one spark plug firing

cubsfan02449

Cadet
Joined
Jan 3, 2011
Messages
18
J30TECCE I have had this motor a couple months. It sat a lot in previous years. Started it last weekend pulled boat up on the bank to let it idle while parking the truck. got back to the boat and it was dead. Cranked on it for 20 minutes and couldnt get it to fire. When i got home pulled the plugs and only 1 plug (top cylinder) is firing. the bottom plug has no spark. I have done a compression test both cylinders have good pressure. I have fuel, cleaned carb 2 months ago and have put at least 15 hours on it since then. I did have a broken wire on the rectifier (red wire). I replaced with new rectifier today. I swapped the coils and still had same spark plug not firing on the bottom cylinder. All wiring looks good from 5 pin connector to power pack to coils. Cleaned all grounds. I thought i did see spark for a split second on the bottom plug when i was cranking the motor and wiggling the power pack wires. I have done a stator resistance check per the Johnson manual and i had .06 when black lead connected to stator yellow/blue wire and red connected to yellow/gray then red again connected to yellow wire. the manual says ohmmeter should read 0.27 +or- 0.05
then the next test in manual says to switch ohmmeter to high ohms scale and connect one lead to engine ground and the other to the stator yellow/blue wire. The manual says it should show a very high reading. When i did this test i had nothing for a reading. Does this suggest i have a grounded stator? I havent had flywheel off. Or is the power pack the culprit. Thanks for any help
 
Last edited:

TheBigSur

Cadet
Joined
Oct 5, 2017
Messages
17
cubsfan02449. You sound like you know what you are doing, so please don't take my recommendations as condescending. But perhaps the spark plug you are using is fouled in some way/manufacturers defect? Have you tried a new spark plug? Also, I purchased a spark plug tester from Harbor Freight ($5.00). You can use it to test if there is spark to the plug (given that it's a new plug), and if it may be a plug wire. This is obviously is the obvious, but sometimes we make it more complicated that it has to be. If the plugs and plug wires check out, then I'd dive into the coil packs and lastly (and hopefully not), the expensive power pack. Good luck and let us know if you get her fixed!
 

AlTn

Commander
Joined
Mar 9, 2010
Messages
2,813
power pack most likely as coil swap revealed both coils to be good...charging system is separate from the ignition system on your engine...if output of the charging side is in question, check your battery voltage to see if it increases with the engine running at more than idle rpms
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,043
My opinion.------Some powerpacks are actually very " cheap " compared to a points condenser system.-----They can be changed in a matter of minutes by most owners.-----No need for a $100 / hr shop to install points / coils / condenser and adjust it all.-----Of course if you know / enjoy maintaining a points magneto that is cheaper.
 

cubsfan02449

Cadet
Joined
Jan 3, 2011
Messages
18
Thanks guys. I bought a spark plug tester last night. I will test spark with it today then I’m gonna switch new plugs around to see if I have a dead spark plug. If problem is the same I will be ordering a power pack.

I did have a problem with my starter assembly (11tooth) engaging the flywheel while motor was on and running at full power. The spring that is supposed to hold that starter assembly gear down worked itself up and stuck inside the spacer. The starter assembly and flywheel were arching off each other for a fishing trip or two before I noticed. Didn’t know if this would take out the power pack?
 
Last edited:

kbait

Commander
Joined
Nov 13, 2007
Messages
2,446
Nope.. electric starting and ignition are totally separate systems on your motor.
 

jasper60103

Commander
Joined
Sep 18, 2008
Messages
2,055
You may want to check out boats dot net for your power pack. They are usually the cheapest for OEM parts.
 

cubsfan02449

Cadet
Joined
Jan 3, 2011
Messages
18
Thanks for the clarification on electric starting and ignition being separate. Spark plug tester confirmed no spark in bottom cylinder. I swapped plugs and plug wires and same result. I ordered a power pack it should be here in the next couple days. Hoping to hook it up and see spark in both plugs. I'll post back my results. thanks
 
Top