Outboard wont turn over

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Mar 2, 2011
489
Compac 14 Charleston, SC
Just acquired a 9.9 hp outboard with a Hunter 23. It's been sitting a few years and won't turn over. I've removed the spark plugs and sprayed some oil in the cylinders. Any other ideas on getting it freed up?
 

BobM

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Jun 10, 2004
3,269
S2 9.2A Winthrop, MA
Marvel Mystery oil in the cylinders should do the trick if it is possible. But if it won't turn over with the plugs out it sounds like it is seized and will likely run like garbage even if it does free up. Hopefully it didn't go for a swim. Did you drain the lower unit and look for water?
 
Feb 10, 2004
3,508
Hunter 40.5 Warwick, RI
In the past I have used Marvel Mystery Oil, but I would also try Kroil or PB Blaster. If it doesn't come loose within a week with this treatment, I would pull off the head. You might find that the powerhead is toast.

I had a 4hp twin cylinder Johnson for my dinghy where the lower seal failed and let seawater into the powerhead. Toast. That one wouldn't respond to any persuation to rotate and after pulling the head I understood why.
 
Mar 2, 2011
489
Compac 14 Charleston, SC
It didn't get wet but Ill drain the lower to check for water. I'm hoping it's just from sitting 4-5 years in the PO's garage. He said it ran good last time. Plugs looked clean and dry too when I pulled them.
 
Feb 26, 2004
21,950
Catalina 34 224 Maple Bay, BC, Canada
Replace the spark plugs...just couldn't resist.

What kind of engine and what year?

I have a 1990 9.9 Evinrude that had trouble starting. Turned out to be the wiring from the kill switch. If you are "engine oriented" check that out, if not, try an outboard shop like I did. Cost a few bucks, but it works fine now.
 

MrUnix

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Mar 24, 2010
626
Hunter 23 Gainesville, FL
It was nice of the seller to include a 9.9 hp Mariner outboard w/ electric start!
Now you know why he was so 'nice' :doh:

Marvel and PB blaster in the cylinder for several days or longer might work.. otherwise you are looking at a tear down, which probably should be done anyway to determine the nature and extent of damage.

Cheers,
Brad
 
Mar 2, 2011
489
Compac 14 Charleston, SC
Ok, just wanted to be sure I'm on the right track. I removed the pull start assy and now trying to turn it with the flywheel bolt. I will update soon.

It's a Merc/Tracker 9.9EL long shaft. I should have checked that it would turn over but the deal was already done for the boat. Paid only $1800 for a 87 Hunter 23 and trailer.
 
Mar 2, 2011
489
Compac 14 Charleston, SC
24 hours later and I'm now able to crank the motor over by hand. It was stiff but PB Blaster soaked it loose! Tomorrow I'll see if it will fire up after I replace the lower unit oil.
 
Feb 10, 2004
3,508
Hunter 40.5 Warwick, RI
I would run it heavy on oil for an hour or so. Mixing a bit of Marvel Mystery Oil would be a good idea also.
 
Mar 2, 2011
489
Compac 14 Charleston, SC
I'm about ready to run it, just replaced the impeller pump and plugs. It's got good compression now.
 
May 9, 2011
70
Hunter 1994 40.5 Ponce Inlet FL
Be sure to check that it is pumping water. If it doesn't pee check the thermostat housing. If you get it started, run on 25-1 ratio for a bit, if it seems a good engine change the pump! If it sat for a while the impeller has lost its flexibility.
If you have scoring in the cylinders it will be most noticeable at idle. Things always smooth out at higher RPM when there is less time for compression to be lost.
good luck
 
Mar 2, 2011
489
Compac 14 Charleston, SC
It starts and idles good, runs quiet and everything but it seems like way too much for a Hunter 23'. At 9.9 Hp and 70 lbs, it's overkill! I may end up downsizing.
 
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