1995 Johnson 150 Ocean Runner, intermittent start.

[Al Hendricks]

disconnected main harness at engine applied power at starter spins great no ignition.

 

[oldboat1]

maybe covered long ago, but how are you checking for spark? Maybe your testing procedure is a problem.

 

[Al Hendricks]

using a dc powered timing light

 

[oldboat1]

good to have, especially for drop cyl tests. Think I would do a backup test with a spark tester.

 

[Al Hendricks]

Unplugged main harness at engine, removed yellow red wire from solenoid and hooked volt meter to wire, with key off jumped starter, engine fired right up with 12.5 volts from yellow red wire. Restored harness and wire cranked engine with key no spark unhooked batt main cable decided to check again when the cable touched the post I saw a spark as if something was powered up key was off, appears I might have a short some where.

 

[bob johnson]

On my 95 115 ocean runner I had an intermittent shut down.. and then no key...nothing....paddle back to the ramp...load up take her home shed start...that happened a few times... a couple times I got it to restart out on the water....turned out to be a short in the harness right in the middle of its length under the floor of the boat!! HOW???? have no idea.... inside the outer thick sheathing... inside the rubber coating of two individual wires.... a short happened!!..... two wires melted and would occasionally contact each other ... they were either the yellow -red or the yellow black...or both......what are the odds???? wasn't in a kink....crazy... it was crazy lucky I even FOUND it!!!!

good luck

bob

 

[oldboat1]

^^Had something similar with an old Chris Craft inboard -- shut down randomly and no start. Took a while, but found a carroded plug in the bilge -- Never understand why they would route the harness down there. It's pretty exciting when the engine suddenly shuts down in the middle of the shipping lane, freighter bearing down.

My guess is the OP has a bad keyswitch. If the engine was jump started and run without the harness connected, seems to point to keyswitch -- although could be a short elsewhere. Depending on how it was jumped and run, rectifier would be burned out if it was run without battery connection at any point -- will want to check for charging, maybe tach operation.

 

[Al Hendricks]

After cleaning and checking more wires restored everything started right up, after at least 2 dozen successful starts, I will be heading to the lake this weekend, for a trial run. Will report the results, thanks everyone for your help.

Al Hendricks

 

[oldboat1]

Good news -- simple fix. I'm a big believer in electrical spray cleaner too. Might be more of a feel good thing, but think it helps in combination with hands-on cleanup. Good luck running.

 

[Al Hendricks]

Tried a start before taking off to lake first try good, second failed, seems I am in same old boat. Tried to start with engine harness disconnected no start.

 

[bob johnson]

sounds like an intermittent short...just like I had...COULD be the culprit.....

bob

 

[oldboat1]

does sound like that.

 

[racerone]

Was the ground cable from battery to engine block ever found to be loose or with poor connections ?

 

[Al Hendricks]

Have not found any problems with ground connections yet. With the main harness unplugged seems it would be in engine harness though, thoughts?

 

[oldboat1]

Well, can try to repeat the prior "fix" -- maybe something a little unique in what you did(?) I think I found the mystery starting short in my old Chris Craft harness when working on a bilge pump.

I like to use a simple continuity tester for this kind of stuff -- probe and light. Also have a long length of wire with alligator clips for checking long stretches in things like wiring harnesses. I would check out the key switch first to make sure it's functional (consistently lights the tester between appropriate posts when switch operated), then check for continuity working back. Can also jumper connections to test (maybe key switch to solenoid, for example). If your multimeter has a continuity setting, can use that -- but harder to use IMO when trying to find shorts. I like have the light and probe in front of me when testing.

 

[Al Hendricks]

Will work on that, might be a few days, my daughter and grandson are visiting for a few days, got to keep an almost 5 year old busy.