Intermittent spark problem?

Okie deerhunter

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Apr 27, 2020
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I have a 1990 Johnson Gt 150 with the 35 amp alternator. J150stlesb. My problem is that sometimes it’s hard to start and slobbers till it warms up a little, then seems to run ok on plane. It may run good initially but turn it off to fish, then fire it up to take off and it bogs and acts like it’s only running on three cylinders. If I stop to fish again it may or may not run right. Motor has been overhauled, along with the carbs. Linkage and timing are correct. I replaced the power pack last year and it helped some, but the intermittent run problem is still there. Tach hasn’t worked in a long time and this problem I’ve been fighting for three years. Is it possible that the stator / charge coil is shutting down when the motor gets warmed running? Or is there something else causing my misery? I hate just swapping parts as that can get expensive. I have a OMC factory manual and still haven’t figured out what is causing the intermittent problem. Help!
 

oldboat1

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Apr 3, 2002
Messages
9,612
Replace the regulator/rectifier, and make sure the cooling system is working properly. Replace the impeller if due.
 

Okie deerhunter

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Apr 27, 2020
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Old boat1- not sure where the regulator-rectifier is located on the engine. As far as cooling- pees a good stream and haven’t had any heat alarms. Water pump and impeller are three years old.
 

Okie deerhunter

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Apr 27, 2020
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Flyingscott- engine was overhauled 2 years ago. I will try to put in on a hose and chk spark when it’s not raining in the next couple of days
 

boobie

Supreme Mariner
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Nov 5, 2009
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20,826
Do a cylinder drop test on it when it's acting up and maybe that will tell you something.
 

Crosbyman

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Nov 5, 2006
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5,811
Old boat1- not sure where the regulator-rectifier is located on the engine. As far as cooling- pees a good stream and haven’t had any heat alarms. Water pump and impeller are three years old.

see pict
 

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racerone

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Dec 28, 2013
Messages
38,888
Facts-----The pee stream is NOT an indicator that the motor is cooling properly.----Water from the pee stream does NOT go through the engine.----Those motors with proper use of the electric primer valve start right up.-----So something is wrong with the engine.----Trouble shooting as suggested must be done !!
 

Okie deerhunter

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Apr 27, 2020
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Crosby man- thanks I found it on top back of the engine. Racerone - I’ll chk the rest of the stuff when I get a good day. Thanks!
 
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