60 HP Slow Turnover

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compgeek

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Jun 16, 2011
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I recently purchased a 1970 Johnson 60 HP outboard. When I remove the spark plugs it will turn over freely. When they are in it acts like it has too much compression and turns over very slowly. Every once in a while it will turn over freely with the plugs in. Any ideas?
 
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Daviet

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Sep 24, 2008
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8,958
Re: 60 HP Slow Turnover

Battery in good shape, all cable connections clean and tight, might want to check starter draw to see if it is going out.
 
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compgeek

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Re: 60 HP Slow Turnover

Daviet, Thanks for the sugestions. I have used jumper cables to connect directly to the starter from my truck. It can't be any cables or connections since I have taken them out of the equation. If it were the starter why would it always crank over like a champ when the spark plugs are out??? Doesn't make sense to me!
 
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Daviet

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Messages
8,958
Re: 60 HP Slow Turnover

Resistance. If the starter is boarder line, with no compression it might spin over great but put resistance (compression) in and the starter does not have enough torque to turn the engine over.
You could take the starter off and have it checked.
 
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compgeek

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Re: 60 HP Slow Turnover

Thanks again Daviet. I understand what you are saying and will have it tested.
 
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Big flop

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Apr 6, 2011
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Re: 60 HP Slow Turnover

Can you turn the flywheel clockwise
easily by hand?
Nothing tight or dragging?
 
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compgeek

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Jun 16, 2011
Messages
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Re: 60 HP Slow Turnover

I took the starter apart and cleaned the brushes and contacts on the armature. Cranks over fine now.

I'm new to the boating world. I bought this old 1976 Starcraft 16' to restore with the 1970 Johnson on it. I suspect I'll be on this site alot!!!
 
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Daviet

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Re: 60 HP Slow Turnover

It would be a great help to you to get the factory manual for your engine.
 
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