Flywheel is easy to spin without spark plugs

[Eppeman]

86' johnson 90hp. I just bought it so I'm not positive when it was last ran. But when putting it on my boat, I noticed a power pack is bad (not getting spark in those plus) but primarily noticed, the flywheel would not spin a full rotation with the starter.

I figured it may be the starter. So took it off and it seemed fine. Pinion was able to fly up and down while off the boat.

Next, took the plus out and turned it over with the starter back on. That's when I noticed the flywheel was able to spin freely as it should! As I put one plug in at a time I could hear it "skipping" until I had all 4 back in and it was back to not making a full rotation. The more plugs i had in it, the longer the "skip" became. Too much compression is what dad called it. But he's not a boat guy.

Anyway, I did some research and tried spraying seafoam in the plug holes, it didn't change anything.

Can anyone tell me some ideas to try or what these symptoms are to look up for myself?

 

[racerone]

No such thing as " too much compression" on these.-----Charge the battery.-----Have the battery load tested.----Take starter apart for inspection of brushes.-----Do an ohm test on armature.-----No money spent to do this inspection !!!

 

[Eppeman]

No such thing as " too much compression" on these.-----Charge the battery.-----Have the battery load tested.----Take starter apart for inspection of brushes.-----Do an ohm test on armature.-----No money spent to do this inspection !!!

To my knowledge, battery is charged. Shows 12. And I have already done everything with the starter. Brushes are in good, Cleaned, and magnets not cracked. What should I be looking for with an ohm test?

 

[Eppeman]

No such thing as " too much compression" on these.-----Charge the battery.-----Have the battery load tested.----Take starter apart for inspection of brushes.-----Do an ohm test on armature.-----No money spent to do this inspection !!!

Also what should the load be?

 

[tphoyt]

If your battery only has 12 volts it’s just about dead. Charge the battery and have it tested.

 

[kbait]

Jump starter motor directly (plugs in) with known good battery (like your car) with good jumper cables with thick wires.. negative to engine ground, positive to post on starter. If it spins normally, bad wiring/battery/solenoid etc. if no spin, then starter is bad.
‘Good luck!

 

[Scott Danforth]

use good cables and bolt the lugs to the battery and the starter solenoid.

jumper cables wont do it.

 

[saltchuckmatt]

Also what should the load be?

Battery should be 12.7 volts or better. Also, you can have good volts but the battery can still be no good, hence the load test. You can take it to an automotive parts store and they can tell you but everything points to a low or poor battery issue. Motor is fine.

Undervolting a starter by the way is hard on it so you should stop doing that.

By the way, if the motor sat, lots of things to check.....water pump, carbs, grease, alarms yada yada yada.....

 

[racerone]

And how did you diagnose that powerpack is bad ?-----Some testing done or your neighbor said ---" must be the powerpack "-----If flywheel does not spin fast there is a " no spark " condition.-------Look this motor over carefully and post compression values BEFORE spending any beer tokens on it.

 

[ct1762@gmail.com]

No such thing as " too much compression" on these.-----Charge the battery.-----Have the battery load tested.----Take starter apart for inspection of brushes.-----Do an ohm test on armature.-----No money spent to do this inspection !!!

maybe he meant it was flooded and thus hydro-locked. only way to do that would be to hook up the pump pulse line backwards i reckon.

 

[oldboat1]

Believe the OP's issue is best handled in a hands-on manner before technical tests -- both or most of which were mentioned. Clean the battery wire ends with sandpaper until shiny bright and tight, likewise for solenoid connections. Use a known good battery and test. If that fails to turn it over, jump directly to the starter with new or newish cables (tests the starter). If the starter fails to turn it over (fast -- 250 rpm or better), take it apart and clean with electrical cleaner, testing when completely dry. Check/replace brushes.

Hopefully, you will find the problem in the first couple of steps.