No spark on 2 out of 4 cylinders.

SigSaurP229

Commander
Joined
Oct 1, 2008
Messages
2,123
1981 Johnson 115hp

J115txcim

I bought this as a "field boat" to restore, see my link below if curious. I was told that the engine had a bad powerpack when I bought it and that is one of the reasons that it was parked. The boat sat in a field for 6 years, in that 6 years mice had gotten under the cowling and had fun with the wiring. So I cleaned the engine up, changed the water pump, spark plugs, and replaced the bad wiring.

I replaced both power packs, and the timer base (the wiring was chewed). I purchased the factory service manual as well.

I assumed that the bad power pack was causing the lack of spark on the two port side cylinders, however both powerpacks were replaced with new. I can tell that the coils on the port side have been changed at some point as well.

Here is what I have done at this point,

Changed both power packs verified strong spark on starboard side no spark on port side.

Swapped the power pack sides moved the starboard to port and port to starboard. Ran spark test again strong hot blue spark on starboard side still no spark on port.

Went ahead and swapped the coils, that gave me the same result, still no spark on port.

Where should I look next the stator?

The rectifier?

All spark tests were run with the black and yellow kill wire disconnected.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Re: No spark on 2 out of 4 cylinders.

[
Where should I look next the stator??] .[/QUOTE]

Timing base
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Re: No spark on 2 out of 4 cylinders.

yep, just ohmn it out in case you got a faulty one.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Re: No spark on 2 out of 4 cylinders.

ohmn test stator then too, and if that doesnt show anything try ohmning stator to ground to test for shorting and after that try Volt testing them
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: No spark on 2 out of 4 cylinders.

Have you got a DVA to volt test them ??
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,270
Re: No spark on 2 out of 4 cylinders.

Check the plug with two brown/yellow wires. Should have somewhere close to 150 volts AC at cranking speed.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
39,396
Re: No spark on 2 out of 4 cylinders.

Check out all the pins / sockets in the electrical connecters.--Something may be out of place and not making proper contact.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: No spark on 2 out of 4 cylinders.

Without a DVA you'll never get the proper voltage readings to check out this system to make sure what is wrong. You're just guessing.
 

SigSaurP229

Commander
Joined
Oct 1, 2008
Messages
2,123
Re: No spark on 2 out of 4 cylinders.

kind of what I thought, just need to bite the bullet and get one.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: No spark on 2 out of 4 cylinders.

All excellent comments. Before you replace any additional big $ items, it's best to get that DVA and do some testing at cranking rpm's. This website has cranking output voltages listed for both the stator and the timer base: cdielectronics.com You need to see something like a minimum of 150 volts out of the stator and about 0.3 volts from the timer base, but check this website for your year's specific voltage outputs. These cranking outputs are more reliable than ohms values. Keep in mind, the engine needs to crank at 250 rpm's in order to generate enough voltage to fire the ignition system. The rectifier is part of the charging system and does not affect the ignition system firing.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: No spark on 2 out of 4 cylinders.

I'm thinking cranking speed too. It is related to the stator output, but also to timer output. Low timer output seems likely here.
 
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