Gearcase slippage on 79 115 Johnny OB...

[redmopar]

'79 Johnson Seahorse 115 20" Outboard<br /><br />Had a slipping problem 2 weeks ago. Turned out to be the prop hub. Got a re-hub. Go to drop it in this week and the outboard is not pulling at all. Figured I had a bad re-hub job. Changed the prop to the spare and nothing. This is true for forward and reverse. Pull off the hood to make sure the linkage is intact and it is. I hear the gears engage as normal and have my buddy walk back to take a look. The prop is spinning incredibly slow. Pull it out and run it on land. With the gears engaged, I can rotate the prop with my hand easily, but not free. The hub is not spinning as the marks I put on there are still lined up. <br /><br />I'm wondering if there is anything I should check before I start disassembling the gearcase? What does this problem sound like? Thanks all.

 

[DHPMARINE]

Re: Gearcase slippage on 79 115 Johnny OB...

Sounds like stripped gears to me.For a quick(er) visual you can pull the bearing carrier,2 snap rings and the retainer plate to see the gears,but I think you need a complete teardowwn.Actually another used gearcase,as parts are expensive.<br /><br />DHP

 

[R.Johnson]

Re: Gearcase slippage on 79 115 Johnny OB...

I would take the gearcase apart. As you discribe, I would exspect a spun pinion gear. If that is the case, forward, and reverse would be gone with it.

 

[redmopar]

Re: Gearcase slippage on 79 115 Johnny OB...

Any ideas what would cause this? The gearcase is the original with low hours(much less than 100.) Would there be any noise associated with this?

 

[OBJ]

Re: Gearcase slippage on 79 115 Johnny OB...

If ya' havn't done so, drain the gear lube and check for metal chunks, sparklers. If you have either or, see the post's by DHP & RJ.....Just for grins.....put it in gear and have someone hold the prop and turn the flywheel by hand. Could be a sheared drive shaft also.

 

[DHPMARINE]

Re: Gearcase slippage on 79 115 Johnny OB...

WOW You should use this boat more often (grin)<br /><br />You probably wouldn't hear a noise.Sudden stoppage of the propshaft would be a cause,like a rock,or wave jumping.Panic shifting would do it (quick forward to reverse)Gear failure is ruled out here,but in 1987 OMC had 40,48,and 50 HP problems.They could't make 10 hours.<br />But of course we are speculating,and won't know until the tear down.Usually the boat just stops due to damage,but if a tooth chipped,failure is later.<br /><br />DHP

 

[redmopar]

Re: Gearcase slippage on 79 115 Johnny OB...

Well, this answers that question. Here is a pic of the magnetic gearcase drain plug.<br /><br />

<br /><br />So something definitly chewed itself up in there. Looks like my hull will be dry for awhile. I was shopping rebuilt gearcases but they seem to run $1000+. Way out of the budget for your college student here. Any idea where I should look for a used gearcase? Checked ebay and the only one I saw was trashed and I'm not even sure it'll fit. If that all falls through I will be attempting to rebuild it myself. Very frustrating considering I just spent the last few months redoing all the electrical on the boat.

 

[G DANE]

Re: Gearcase slippage on 79 115 Johnny OB...

Watch Ebay a little longer, they show quite often, and prices around 1000 are the high ones.

 

[G DANE]

Re: Gearcase slippage on 79 115 Johnny OB...

Isnt this exactly the same - 85 or 115 is equal, late 70 ties http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=26455&item=4512696716&rd=1

 

[Silvertip]

Re: Gearcase slippage on 79 115 Johnny OB...

Try www.twincityoutboard.com

 

[redmopar]

Re: Gearcase slippage on 79 115 Johnny OB...

G Dane, that looks like it. I'm trying to establish shaft legnth now. He has on there he measured the shaft to 21 3/4 inches but i'm not sure where he measured it to(top of water pump or cav plate.) It should be a good deal if it fits that is.<br /><br />Smoke, i'm contacting twin city now. Thanks for the link. Should make for a tight christmas.<br /><br />Thanks all.