78 Johnson 150 ignition help--one bank dead

tgergen

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Jan 1, 2003
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Howdy all..nice forum!<br /><br />I was given a 18' Glastron open bow "ski boat" with a 78 Johnson 150 by my grandfather..nice grandfather!<br /><br />At any rate, the other week, after fishing, we started her up and headed back. Motor would not go past 3k, and would sputter badly at anything above 3k. Ran fine under 3k.<br /><br />Pulled the plugs...all starboard plugs were nice and clean. All port plugs were cruddy and oiled...running rich I suppose.<br /><br />I searched previous posts and found that it could be (most likely) either the power pack, stator, or a bad ground. I inspected the grounds and they all look good. No corrosion, etc.<br /><br />Also, I cannot locate a repair manual for this motor. Any ideas where I can?<br /><br />I would love to fix this myself, but without a manual, I have no idea how to test the stator or powerpack...and what the names are for the various components...it took me a week to figure out what the little black box was called (powerpack), but I knew by inspecting the motor and wiring that it controlled the spark for one bank.<br /><br />Also, the starboard Powerpack appears newer than the port one. Starboard is black in color, port is and old wornout brown color. FWIW.<br /><br />Any help would be appreciated....I am not sure where to begin.
 

Waterbugtoo

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Nov 19, 2002
Messages
245
Re: 78 Johnson 150 ignition help--one bank dead

Thats usually a pack, but check the stator to make sure.
 

tgergen

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Jan 1, 2003
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Re: 78 Johnson 150 ignition help--one bank dead

Also, I believe it is a CD ignition for some reason. Must of saw it somewhere on there when inspecting it...LOL!
 

tgergen

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Jan 1, 2003
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Re: 78 Johnson 150 ignition help--one bank dead

Thanks Waterbugtoo...but I have no manual, and thus, no idea how to check the stator....<br /><br />Do you know where I can find a manual for my 78 Johnson 150?<br /><br />TIA, Tim
 

rons boat

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Dec 28, 2002
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Re: 78 Johnson 150 ignition help--one bank dead

Check for spark on both banks, ususally one of the power packs dies. It is not always the pretty one that survives.
 

tgergen

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Re: 78 Johnson 150 ignition help--one bank dead

Waterbugtoo - Thanks for the link...good info.<br /><br />Ron -- The "old" looking powerpack is on the side that the plugs are all loaded up with crap. So I assume it is that one that is bad....but I will check them both for sure!<br /><br />Thanks for the replies fellas... Tim
 

tgergen

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Jan 1, 2003
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Re: 78 Johnson 150 ignition help--one bank dead

Thanks...I appreciate that. I will order one as soon as I get the serial number...Tim
 

rons boat

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Dec 28, 2002
Messages
210
Re: 78 Johnson 150 ignition help--one bank dead

Tim I didn't get your reply on whether or not you got spark on one side when you ran it in the driveway just enough to turn it over. Sounds like you got it though. The reason for the test is to make sure trigger is ok. It usually is one of the pack and surprisingly enough most of the time it is not something you can see. Rarely will both packs die at the same time.
 
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