Possible Timing Issue

[FreeBeeTony]

Been having a problem while trolling. '95 Johnson 175.
Engine started to sputter/miss and smoke alot, when put into neutral RPM's shot to ~2000.
Was able to return to the dock....when put back into gear it slammed into gear (idling @ 2000)....was still sputtering/missing. After slowoy increasing the throttle it seemed to "clear-out" and ran fine back to the dock @ 4000RPM.
Then when in a no-wake zone the problem appeared again, this time when the sputtering/missing started I put it into neutral and the RPM's shot up to 2000 again, I removed the cover and moved the timing arm..........no affect; after fooling with it for a minute the problem went away, I was even able to repeat it by increasing the timing while in neutral w/o touching the throttle mechanism.
After getting back to my slip I removed the cover over the timing wheel and removed the timing wheel and cleaned the optical sensor.
What else could increase the timing as I suspect is happening......strange thing is when it gets up to speed it runs great.

Any insight would be appreciated.

 

[Chris1956]

I had an issue on a similar motor. The timing linkage tended to stick, keeping the RPM high, when I cut the throttle.

You might slap a timing light on it to see if the timing is going back to idle settings.

 

[FreeBeeTony]

Thanks for the reply. I did remove the hood while it was idling high (2000) and the linkage was actually in the correct position......would have to be pretty far off to idle that high and the throttle plates were close . I am going to keep a timing light on board to check next time. I'm wondering it it could be an intermittent power pack. I'm going to call CDI on Monday

 

[FreeBeeTony]

Had the problem today again after returning to my slip.........ran great the whole morning.
After docking while idling the RPM's were fluctuating. Put a timing light on it and saw it advanced to ~20* BTDC.....then returned to ~8*ATDC.
Went back and forth a few times while I was monitoring it. The timing arm did not move during this time.
What could cause this?

 

[flyingscott]

Could be a bad OIS sensor

 

[FreeBeeTony]

Anyway to test it?
Seems like is is going to max advance, which I believe is 20* BTDC.

 

[flyingscott]

Yes with the tester they make. CDI makes it for $300 A guy on ebay makes them for about $80.
https://www.ebay.com/itm/Johnson-Ev...937476?hash=item289515fac4:g:bEwAAOxyn9BRaadt

 

[FreeBeeTony]

Interesting! I actually bought 1 of these when I 1st bought the boat, I will have to check it out.
Wondering if it will indicate an intermittent sensor?......Probably be difficult.
Maybe just replace the sensor.........hate to play swap-tronics.
Would a bad sensor put the engine into max advance?

 

[flyingscott]

Yes it will tell you if the sensor is bad. If you bought that one he sends great instructions with it. You also need that to time the motor correctly.

 

[FreeBeeTony]

Thanks.....will need yo look st the instructions and check the sensor. sensor hopefully this weekend. I will update with results.

 

[FreeBeeTony]

So.....tested the sensor today.
Initial results were the sensor was not picking-up the pulse for each cylinder, only the sync pulse.
Confirmed the tester was working properly by checking it on the stb engine (have twins).
Removed the timing wheel, cleaned the sensor w/ spit and a microfiber cloth, reinstalled and retested.....now picking up both the cylinder a sync pulses.
Started engine and ran the same. Plan on running the engine and monitoring for the problem.

It appears the sensor has 2 levels: 1 for the sync pulse and 1 for each cylinder.
Question: will the engine run if the sensor only picks-up the sync pulse?

 

[FreeBeeTony]

BUMP
Was hoping for an answer to my question: will the engine run if the sensor only picks-up the sync pulse?

 

[FreeBeeTony]

one last try with a bump

 

[FreeBeeTony]

guess I stumped everyone?