Johnson 70hp motor

[DaBADD1]

could someone tell me the year of this motor with the model number being 70 SL 75B

 

[DaBADD1]

Re: Johnson 70hp motor

and if you know a solution to the problem of without the plugs in motor spins perfect but with plugs in and under compression wont spin but barely

 

[ob]

Re: Johnson 70hp motor

Your motor is a 1975.I don't understand your question.Are you saying it's not cranking strong with the starter while plugs are in?Is your battery fully charged?Starter connections clean and tight?

 

[DaBADD1]

Re: Johnson 70hp motor

battery is fully charged. posts are clean and tight. under compression with the plugs in the starter barely turns it over. could it be timing or starter problems

 

[Chinewalker]

Re: Johnson 70hp motor

More than likely, it's the starter. The brushes do wear with age and aren't too difficult to replace...<br />- Scott

 

[blazed4x4]

Re: Johnson 70hp motor

Probrobly the starter, but before ya send it out, crank motor for a couple of seconds and feel the battery cables near the battery and near the motor. If their fairly warm or hot its time for replacement.

 

[JB]

Re: Johnson 70hp motor

"Posts are clean and tight". Good.<br /><br />What about other connections? The negative cable connection to the block is a constant threat on that engine, because it is usually bolted to the steel bypass cover.<br /><br />Put a voltmeter from the starter hot terminal to the negative battery post when cranking. If it reads near 12volts you have a starter problem, If it reads below 9volts you have an electrical connection problem.<br /><br />Good luck.