Possible Intermittent Timing Problem

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.

Put a timing lite on it,could be going into quickstart.
Could have a throttle plate sticking open.
Did your timing wheel have any cracks on it?

If it was quickstart it wouldn't be jumping the 2000RPM;s. Thought about a timing light, didn't have one at the time.
Throttle plates not open, this problem appeared out of no where while I was trolling!
No cracks noticed on timing wheel.

Im sorry,you are right,limits@1100.

NP.............any other ideas?

While swimming today I noticed the exhaust ports were loaded up with what looked like an oily residue.....going to keep an eye on it!

Again,put a timing light on it..

Did the screw come loose on t timing tabs? Did the adjustment on the carbs change? Air leak in the manifold? Air leak anywhere?

Boat ran well at 4000RPM cruise today and on the way back tried WOT....hit 5200RPM.
Hoping all is well and cleaning the optical sensor was the fix.
I don't think the timing could be off if it ran this way today.......unless it's an intermittent problem coming from the power pack.

Rwbutler said:

Again,put a timing light on it..

Click to expand...

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.
What could cause this?

So.....tested the sensor today. Using the OMC-like timing tool....connects to sensor & 12V,has 2 LEDS's (Cyl & Sync)
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?

Bump...........

Anyone have an answer to the following?

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?