1970 85hp starting issues

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smoke14

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I recently bought a used boat with a 1970 Johnson 85hp motor. The motor turns over strong but wont start, have fuel, new plugs and wires. Seller claims power pack is bad. How can I test to verifiy what is really going on. First boat ever owned, looked through search but it appears every motor is different. Any good direction would be appreciated.
 
tashasdaddy

tashasdaddy

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Re: 1970 85hp starting issues

use a spark tester and see if you have spark on all cylinders. i personally would not put a lot of money into that motor, that vintage was known for blowing expensive power packs.
 
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smoke14

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Re: 1970 85hp starting issues

Wasnt looking to get flamed for buying it just looking for direction on how to test the power pack or other ignition components.
 
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smoke14

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Re: 1970 85hp starting issues

Ok performed the spark test on the engine was not getting spark out of the coil. I replaced the amplifier and coil, came in a kit. Installed new parts rechecked spark, getting spark when starter engages and when starter disengages but no spark when starter is spinning the motor over :confused:. Have 12v on power wire with key on. Any suggestions?
 
packkratt

packkratt

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Re: 1970 85hp starting issues

smoke14 said:
Ok performed the spark test on the engine was not getting spark out of the coil. I replaced the amplifier and coil, came in a kit. Installed new parts rechecked spark, getting spark when starter engages and when starter disengages but no spark when starter is spinning the motor over :confused:. Have 12v on power wire with key on. Any suggestions?
Click to expand...

This may sound daft, but make sure your battery is fully charged and in good condition (try another if you have it) if the motor is not spinning fast enough or the voltage is too low during cranking the plugs may not fire,
 
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