1997-70hp Johnson Possibly LOCKED up. HELP!

crafty72

Cadet
Joined
Feb 24, 2012
Messages
7
I am a bit shocked to say the least. I have been running my boat fri-mon with no problems. I even made a 20 mile run on Sunday. Come Monday afternoon i went from the dock to the launch about 2 miles away and it ran fine. I loaded up and got it home around 2100hrs. Monday i had cruised a big block of woods( im a forester ) and was toast while i got home so today i went to flush my motors.(I was in brackish and salt water) My kicker motor cranked right up and flushed as usual. As i hooked the muffs on the Johnson and turned the key i heard the start engage but nothing. pulled the cowl and watched it strike the flywheel but flywheel never moved. So i tried to turn it by hand and nothing. So i made sure it was in neutral and checked the prop. prop spins free. put it in gear and tried to spin the prop and couldn't bar over the motor even with all of my weight on the prop. Hooked a rope to flywheel and it moved a few inched after really pulling and then i couldn't get it to move again. I'm assuming the pistons are froze but i cant understand how. I pulled the plugs and sprayed some WD40 in block to hope it'll free up the cylinders (if this is the case) and ill let it set over night and try again tomorrow.

Could it be the gear case if the prop spins free in neutral? or am i thinking about it wrong. Or would this lead to the power head?

Cant someone please give suggestions and lead me into the right direction?

BTW when i pulled the plugs the bottom and middle plug was gummed just and little bit and these are new plugs as of 3 weeks ago. The motor has been ran about 8-10 times since installed.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

The propeller will of course spin freely when in neutral. Drop the lower unit which will determine if it is indeed the powerhead OR the lower unit that is locked up.

NOTE: WD40 has a cutting base... not a good idea to be squirting that into the internal portions of the engine.
 

crafty72

Cadet
Joined
Feb 24, 2012
Messages
7
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

That is good to know. I have been in conversations and heard before if a boat is sunk to flush the engine and spray WD in the cylinders to keep them from rusting. so that is what is did.

When i drop the lower unit tomorrow what am i looking for. ??????
 

Scurvy Knave

Petty Officer 2nd Class
Joined
Apr 4, 2013
Messages
128
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

if you can turn the flywheel by hand after you drop the LU, then the gearcase is locked up. Otherwise, it's the powerhead.

Good luck!
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

Yep... What "Scurvy" said.
 

crafty72

Cadet
Joined
Feb 24, 2012
Messages
7
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

I will be dropping the LU tomorrow to troubleshoot more. I likely will be having a local shop do the work due to time constraints and me having a big tourny in 3 weeks. My question there is, Could someone give me some estimates of Lower unit rebuild and powerhead rebuild cost...Or a round about so i have an idea of what im looking at price wise.

Thanks for the replies so far..
 

Scurvy Knave

Petty Officer 2nd Class
Joined
Apr 4, 2013
Messages
128
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

Cost wise, it really depends on what the problem is.

A broken shifter cradle piece stuck in the pinion gear might not be too expensive to fix if the gears aren't chewed up. But who knows?

As far as the powerhead, I don't know what the cost for a shop to do it would be, but I suppose that it can get real expensive if it requires are rebuild of the crank. Parts availability might also be an issue.

Wish I could be more helpful. Good luck
 

crafty72

Cadet
Joined
Feb 24, 2012
Messages
7
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

Just an update. I dropped the LU and all is well there. Gears are good. Impeller and all the cooling parts on that end are good. Still can't turn the flywheel for anything.

At this point I'm debating on just junking the motor and finding another. I can't afford to have my boat down thru the summer.
 

Jim311

Petty Officer 2nd Class
Joined
May 31, 2011
Messages
169
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

Has the starter bendix dropped down? If the nut comes loose on the starter bendix, it will bind up against the flywheel, and then you won't be able to turn the motor or start it because it's all bound up. Make sure the bendix has dropped down before you trash the whole motor!
 

BonairII

Commander
Joined
Jun 7, 2011
Messages
2,727
Re: 1997-70hp Johnson Possibly LOCKED up. HELP!

If you rule out a frozen starter and/or LU as the cause....then it sounds like its time to pull the heads and take a look at what's going on in there.

Make sure to visually inspect under the flywheel to make sure that nothing came loose and jammed in the flywheel. (Do this before pulling heads off).
 
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