Re: 1975 Johnson 135 No spark starboard side

[wiscoboater]

Thank you Don for your help!
Here’s the background on the motor. I purchased it from a friend that purchased it from the original owners son. The original owner is now diseased. The boat was primary power on his Lake Michigan salmon fishing boat. That tells me the motor was most likely run 3/4 to wide open out to the days hot spot and then spent a lot of time trolling between 2 and 3 mph, then run wide open back home again. The Son stated that before his Dad passed the motor developed some running issues, down on power, running rough. He replaced the rectifier? Not sure why he started there but he did. No change in running condition. As his Fathers health deteriorated, the boat was winterized and sat for 3 years before my friend picked it up. I bought the motor about 4 months ago. When I did, I did a compression test first thing. My low cylinder is 149psi dry, high cylinder is 154 psi dry. I have not started it at this point. I have only spun it with the starter, plugs out and grounded. Thats where I found the dead bank. It was spinning over very well when I did that test. Next test was with new plugs installed (tested on another motor, known to be good) and an inline spark tester. It’s the adjustable open air type, gap set at 1/4 inch. Again, spark like crazy on the port side, starboard nothing. I had a long conversation with Dan today and he instructed me to shoot some OMC engine tuner into the carb bowls through the venturies and let it soak in there for 24 hours to loosen any gum or varnish and then try to start it with fresh fuel tomorrow. He said it may pick up the 2 dead cylinders once it get going and picks up some RPM’s. So that’s where I’m at right now. Any additional advise welcomed!