1978 85 HP Johnson

[stevengreen]

Need some direction....Just bought a 1978 Glastron Sportster XL with an 85 HP Johnson Javelin today. Boat is in great condition and has been garage kept since new. Over the last week, prior to purchasing, I met with the owner twice and we ran the motor at his house. Motor ran strong every time with no obvious issues. The seller is an older man with a nice home and a few acres, and is also a retired engineer. I felt very confident that he was shooting straight with me about the overall condition of the motor. Today, the day I paid the man, I took the boat out. Ran great for 30 minutes and then suddenly stopped running at about 3/4 throttle. When I try to restart the motor the stater engages into the flywheel but will not spin it. In neutral the prop will spin but the flywheel will not. In gear neither the flywheel will spin nor the prop... I put it in reverse and tried to spin the prop and with just a tiny amount of force and it broke free and would spin both ways... Put it back into forward gear and same thing, prop will not spin nor will the flywheel..... Obviously the motor has seized up and now I feel like making this guys eye black.... Does anyone have any idea where I should start tearing into this motor to figure out the problem? I feel like I should start at the lower unit and remove it to see if I can get the flywheel to spin which, if it does, would tell me that the issue is in the lower unit, correct? If I do this and it does not spin then what? Also, after I loaded the boat on the trailer after I had to get towed in, I unscrewed the drain plug on the lower unit to check the gear oil and it had a ton of pressure on it. It blew gear oil all over me and was obvious from the sound that it was under some serious pressure...

BTW, Not only do I have a motor with problems, a bank account missing a small, but decent amount of money, I now have to fix a part of my fence where I took some aggression out on it tonight...Not the way I was raised but damn it felt good...

This was supposed to be the boat for my wife and kids I until I finished school.....Any advice in this situation would be greatly appreciated! Thanks guys!

Steve,

 

[oldcatamount]

Re: 1978 85 HP Johnson

The lower unit is the place to start. There is an air leak of some kind in there. Possibly a crack in the housing, bad seals, or both. How a lower unit can build pressure is something I can't answer but I do know it shouldn't have pressure as extreme as you described. It could be sucking exhaust gases in there somehow (total guess).

 

[F_R]

Re: 1978 85 HP Johnson

Steve, I'd say you are correct, remove the lower unit and see if it frees up the powerhead. I'm betting it will since you said the prop will spin both ways in reverse. If you do find the problem is in the lower unit, there is no way out of it--it has to come apart to see what broke. I'm betting on stripped gears. But that's only an educated guess.

Take it easy on the seller. There is no way he could have predicted a catastrophy like a sudden busting of a gear tooth. Well, maybe that isn't true. Has he been in there and seen something about to blow and just put it back together and found a sucker to unload it on??

I have great respect for oldcatamount, but I don't buy the air leak theory. If it had leaked in, it would have leaked back out. Just my opinion.

 

[oldcatamount]

Re: 1978 85 HP Johnson

F_R, how could pressure build up in the housing like that? It seems air has to be getting in there to create the pressure or, the gear oil is heating somehow.? I haven't encountered this before and I'm as curious as Steve is.

 

[TraskRiver]

Re: 1978 85 HP Johnson

I would imagine heat would build pressure. Normal? I don't know. You have a sealed liquid building heat with no venting. Should be a sign that your seals are good. At least they were.

 

[stevengreen]

Re: 1978 85 HP Johnson

Good morning guys.. I am going to start with pulling the lower unit and I will check back in as soon as I do. Thanks for getting in on this with me.

 

[F_R]

Re: 1978 85 HP Johnson

OK, you guys, when I was getting paid to fix these things, I wore a white uniform-type shirt. Seems like every time I got an nice clean new one, I would let my guard down and uncork one of those pressurized gearcases and get a black speckled shower. Some oils will do that (build up pressure). I suppose 90 weight car oil would be the main culprits. Some of them downright stink too. Glad my wife knew how to get those shirts clean.

 

[stevengreen]

Re: 1978 85 HP Johnson

Ok guys....Removed the lower unit and now the flywheel will spin.... What next????

 

[F_R]

Re: 1978 85 HP Johnson

Gotta open the gearcase to see what busted. You won't know till you get there.

 

[oldcatamount]

Re: 1978 85 HP Johnson

Can you turn the prop shaft and/or the drive shaft? Chances are very good the gear housing will have to come aprt and see what's going on. Depending on what you find in there, I suggest a Service Manual specific to the motor should be on the list. It could be a simple fix though so see what it is first.

 

[stevengreen]

Re: 1978 85 HP Johnson

Prop shaft will spin, drive shaft will not.....

 

[F_R]

Re: 1978 85 HP Johnson

More and more, sounding like busted gear teeth. Can't hardly stand the suspense.

 

[stevengreen]

Re: 1978 85 HP Johnson

More and more, sounding like busted gear teeth. Can't hardly stand the suspense.

Yea me either!! Headed out to my uncles place to open up the unit.. He would fit right in with you pro's on here if he ever got online. I will update after we get it opened up. If it were to be busted up gear teeth, is it possible to replace these parts individually? or would I be looking at a new lower unit. All shops around are telling me that it will cost more to fix these lower parts than a complete rebuilt unit... Anybody ever been in this situation, any advice?

 

[F_R]

Re: 1978 85 HP Johnson

Well it certainly won't be cheap. But first lets see what broke.