1996 Johnson 175 Oceanrunner OK on Land, Not at Sea - Power Pack, Optics, Reg?

MaineMike

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Jul 1, 2013
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Sorry for the novel...

I?ve got a 1996 J175SLEDB new (to me) that starts right up fine in the driveway. It idles down as expected from ~1100 to ~800, runs fine on ears and revs up fine but dies on the water. I?ve been told it has less than 300 hrs and compression is 120 all around.

First time out it stalled at the dock and we could not get it running again - unless I wiped the plugs dry ? although they did not seem all THAT wet. Right now Im going to attribute it to not priming correctly and a poor battery, but maybe not?

I found a you tube video showing my exact same issue and followed his carb cleaning and gas treatment with B12, seemed to help ? but then it runs fine in the driveway anyways..

Second time on water went a bit better until trying to get on plane. Engine started to skip, then died around 2400rpms. Got it started again, and tried again, died under load. Could get it to start and limped back to launch area.

Ran some laps near the ramp ? would idle ok, but repeatedly dies at higher RPMS. Noticed water squirting hard out of port ?water pressure relief? nipple on the head. The starboard nipple has a screw plugging it, so we plugged the port one too. What?s the deal with these nipples/fittings?

Could not get it started once tied up at dock. Took fuel filter out and saw some debris in screen but nothing serious ? will replace filter.

When turning it over on the dock we could see gas going into the air intakes- so it has fuel.

Think we had real bad and old gas, I went back home, got 3 Gal tank with new gas, hooked that up back at the dock, could not get it to fire at all. Nothing. Head was warm, but not really hot.

Trailered it back to driveway, inspected and clean the optical sensor, inspected optical timing wheel/slots, wires, plugs, found NO spark on one port plug, but then intermittent spark ? could tell it wanted to go, but wouldn?t ?catch?. Heads still warm.

Now, next day, I go to start it up and right off the bat she fires up. Are you kidding me?!

The boat has new fuel line from the tank, water separator, bulb, battery, cables, and new helm controls.

As a sanity check I syphoned fuel from the output of the water separator into a 1 gallon glass jug, it was clean, a bit amber, but no water of debris.

I?m thinking this may be a heat related issue with the electronics, so I?ve already decided to replace the power pack, or optic sensor, but would like to hear other ideas on what may be the issue.

TIA,
Mike
 

MaineMike

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Joined
Jul 1, 2013
Messages
2
Re: 1996 Johnson 175 Oceanrunner OK on Land, Not at Sea - Power Pack, Optics, Reg?

Update on this:

Changed power pack (new form CDI)
Changed Optics (new from CDI)
Changed wires (new from CDI)
Changed fuel filter
Gapped plugs 0.030
Plus wet, not fouled
Primer bulb firms up then is normal when running
Verified Faststart works (idles remains high disconnected, idles low when grounded or after warm up/5 secs)
Verifed temp switch works (ohms open and alarm when grounded)
Verified manual enrichment closed

Same result.

Any ideas from the experts?
 
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