1994 150 after few minutes it's like you turn key off let cool for 5 min and will go another few min and repeat

Cory76044

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1994 johnson 150 was on lake this a.m. and during a 15 min run it was like someone turned key off. Had to let sit for about 5 min and would run flawless again for about minute or two and same thing. Seems electrical in my opinion, maybe a sensor? I cleaned and checked ignition switch wiring and looked for sign of arcing wires everything seems to be in order. If I let set one min after stall it would run maybe 30 seconds then stall. If I let sit longer it would run longer before stalling. I tried idle and same result, seems like a sensor getting hot. I appreciate any input.
 

McGR

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I just had a somewhat similar problem with my '95 90hp looper (same ignition system). Being that the problem was intermittent, it would be difficult to diagnose on the driveway. I decided to take a shot in the dark and replace the (original) stator... nope, wasn't it. Then replaced the power pack... wrong again. I had an old optical switch in my parts stash, decided to try it... bingo, problem solved.

Yeah, these sort of issues can be a pain to diagnose. I suppose you can at least see if you're losing spark after five minutes and at least narrow it down to the ignition system. If you can get it to misbehave under controlled circumstances, you can probably troubleshoot the issue. If not, you are sometimes relegated to parts swapping.

At the end of the day, I dropped about $500 to get my motor running properly again. No regrets, still probably much less $ than taking it to the shop + now I have spare parts for next time the ignition acts up.
 

saltchuckmatt

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1994 johnson 150 was on lake this a.m. and during a 15 min run it was like someone turned key off. Had to let sit for about 5 min and would run flawless again for about minute or two and same thing. Seems electrical in my opinion, maybe a sensor? I cleaned and checked ignition switch wiring and looked for sign of arcing wires everything seems to be in order. If I let set one min after stall it would run maybe 30 seconds then stall. If I let sit longer it would run longer before stalling. I tried idle and same result, seems like a sensor getting hot. I appreciate any input.
Yes, my guess would be optical sensor first then power pack. Start by testing the sensor with an ohm test ....many online forums on how to do this.
 

Cory76044

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I just had a somewhat similar problem with my '95 90hp looper (same ignition system). Being that the problem was intermittent, it would be difficult to diagnose on the driveway. I decided to take a shot in the dark and replace the (original) stator... nope, wasn't it. Then replaced the power pack... wrong again. I had an old optical switch in my parts stash, decided to try it... bingo, problem solved.

Yeah, these sort of issues can be a pain to diagnose. I suppose you can at least see if you're losing spark after five minutes and at least narrow it down to the ignition system. If you can get it to misbehave under controlled circumstances, you can probably troubleshoot the issue. If not, you are sometimes relegated to parts swapping.

At the end of the day, I dropped about $500 to get my motor running properly again. No regrets, still probably much less $ than taking it to the shop + now I have spare parts for next time the ignition acts up.
Thanks for the input. i will update progress
 

Cory76044

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Replaced optical sensor today, launched boat and 120 seconds into run and it's literally like someone turns the key off. Tried to start immediately after and will fire for one second then dead. Wait 5 min and I'm good for another 90 second burn then I'm eating the windshield. Moving on to power pack.
 

racerone

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Find black / yellow stripe wire.-----Pull plug apart and test run ??
 

oldboat1

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So is the motor overheating? 160F give or take at top of heads -- too hot to touch.
 

Cory76044

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So is the motor overheating? 160F give or take at top of heads -- too hot to touch.
No sir. I can touch heads I also felt around for anything super hot And Not getting warning light on gauge. If got hot my understanding it goes into rev limit limp mode. I thought about checking t stat so I just ordered them today it's been few years. Power pack will be in Friday I will change and new coils. The timing of stall from cold start doesn't matter if on pad at 4500 rpm or in neutral at idle , about 90 seconds and it's like you turn key off.
 
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Crosbyman

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try a electronic cooling spay on various suspect compoments. if extra cooling fixes it then you found the flaky component.

inverted can of keyboard spray may work and not $$$$
 

909

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try a electronic cooling spay on various suspect compoments. if extra cooling fixes it then you found the flaky component.

inverted can of keyboard spray may work and not $$$$

Excellent tip Crosbyman

Take notes boyos
 

Cory76044

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Replaced power pack and same result. Immediately after stall if you start it kills itself in seconds. Wait 2 minutes it runs for 45 seconds the shuts down. No missing no coughing, I did notice tack jump up a couple hundred periodically and fall right back down, Nothing crazy. Have coil packs and t stats coming Tuesday. I’ll continue to test everything I can find and read about with standard ohm meter. Thanks for all the advice and I’m open to any suggestions for sure.
 

saltchuckmatt

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Replaced power pack and same result. Immediately after stall if you start it kills itself in seconds. Wait 2 minutes it runs for 45 seconds the shuts down. No missing no coughing, I did notice tack jump up a couple hundred periodically and fall right back down, Nothing crazy. Have coil packs and t stats coming Tuesday. I’ll continue to test everything I can find and read about with standard ohm meter. Thanks for all the advice and I’m open to any suggestions for sure.
More likely stator than coil packs.... When this all happens are the plugs wet when you look at them?
 

McGR

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It would seem a coil failure would likely result in dropping spark a cylinder or two, but the motor would probably still run. I would be inclined to take a closer look at the stator. As far as the ignition goes there are three coils to be concerned about on the stator assembly - one power coil that powers the power pack when running and two cd ignition charge coils that provide high voltage required to power the primary sides of the ignition coils. Here are some static and running test parameters that can be checked with an Ohmmeter and peak reading voltmeter.

CD Ignition Charge Coils
Wire Colors (Coil 1) : Brown(+) to Brown/Yellow(-)
Wire Colors (Coil 2) : Brown/Black(+) to Brown/White(-)
Resistance : Approximately 550Ω
Voltage : (DVA Peak) 150V cranking, 400V running at idle.

Power Coil
Wire Colors : Orange to Orange/Black
Resistance : Approximately 55Ω
Voltage : (DVA Peak) 12V cranking, 15V+ at idle.

Hopefully this helps.
 

Cory76044

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Jun 17, 2020
Messages
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It would seem a coil failure would likely result in dropping spark a cylinder or two, but the motor would probably still run. I would be inclined to take a closer look at the stator. As far as the ignition goes there are three coils to be concerned about on the stator assembly - one power coil that powers the power pack when running and two cd ignition charge coils that provide high voltage required to power the primary sides of the ignition coils. Here are some static and running test parameters that can be checked with an Ohmmeter and peak reading voltmeter.

CD Ignition Charge Coils
Wire Colors (Coil 1) : Brown(+) to Brown/Yellow(-)
Wire Colors (Coil 2) : Brown/Black(+) to Brown/White(-)
Resistance : Approximately 550Ω
Voltage : (DVA Peak) 150V cranking, 400V running at idle.

Power Coil
Wire Colors : Orange to Orange/Black
Resistance : Approximately 55Ω
Voltage : (DVA Peak) 12V cranking, 15V+ at idle.

Hopefully this helps.
I appreciate the info. Will check in a.m. before work.
 
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