1974 Johnson 50hp Stuck.

[Chrisravosa36]

Got this motor off craigslist for 50$, wanted to get some more experience in the marine motors, I have worked on a 71' 5hp sears, totally different engine. I understand the basics of this motor, I bought a service manual for it also. Now for the bad news, looks to be stuck. The owner said he ran it, then let it sit for about 4 years, humidity must have got to it... I also purchased a engine release kit, its guaranteed to work, or you money back so I though why not. In the meantime im looking for any other solutions? I've heard diesel fuel might work? Also was wondering what lo[[charged means, and powershift ll means, thanks!

 

[flyingscott]

Get a good manual and take the lower unit off make sure that's not what's stuck. You can use brake fluid ,tranny fluid, penetrating oil or diesel.

 

[oldboat1]

Before taking anything apart, try shifting in and out of gear. It looks to me like it's in gear -- if so, try to get it in neutral and then try turning the flywheel. If it seized up while running (from overheating, no oil, etc.), be good to know that. PO give you any history?

 

[gm280]

You didn't specify what manual you purchases, but I would absolutely suggest to buy the factory, year, HP, model specific shop manual for that engine before doing anything else. It is the bible for your engine and will go through every part of it in pictures and written detail. After market manuals are too general. There is a huge difference. JMHO!

 

[flyingscott]

Shifting in and out of gear won't matter if the driveshaft is seized on the bearings or a gear is stuck. Take the lower off be a good time to find out if it even comes apart.

 

[racerone]

Will the flywheel move just a little bit back and forth , yes or no ?------Powershift II means that is a mechanical shifted unit with oil pressure assist.

 

[oldboat1]

Best to keep it simple initially, and not jump to conclusions. But it's true the l.u. will need to come off anyway because the impeller will need to be replaced. Any additional history?

[ed. flurry of responses -- try the flywheel again as R. suggests, and post what you find.]

 

[Keyboardman]

I have the same engine and found the original factory service manual for it at DIYrepairmanuals online. Only paid $35 for it. and is definatley worth it.

 

[flyingscott]

It's not jumping to conclusions when you eliminate a potential source of the problem. I had an 85 70 hp this summer that somebody locked up they swore the power head was seized up. I bought it for a song the flywheel wouldn't budge an inch. Pulled the lower unit off and the motor started right up bearings were rusted tight in the lower. So in 1/2 an hr I found out I had a much bigger problem than the power head. Your lower unit on that motor is by far the most valuable part also the most expensive to fix. A lot of parts for those are NLA

 

[Chrisravosa36]

I can shift the motor in, and out of gear, forward, rev and neutral work. I believe he said it was humidity in the basement that got it. I did purchase the factory manual for that hp, and that year so that's all set. Il try taking the lower unit off tomm. I tried doing it today, but 2 of the bolts wouldn't budge, squirted some wd40 and let it sit overnight.. And no the flywheel wont move at all. What should I try first? Diesel? Mystrey Oil? Overall cosetically the lower unit seems alright, I drained the oil, found out there was some water in it (4oz), but luckily he kept it in a heat basement. I look into the spark pluh holes, they were pretty darn black, all over the piston from the carbon.

MANUAL: 1974 Johnson 50 HP Service Repair Shop Manual FACTORY Outboard OEM


*UPDATE, talked to the previous owner, they said it wasn't stored properly, sat outside, covered for 2 years. they tried magic mystery oil, with no luck.

 

[oldboat1]

Sounds encouraging re. the l.u. -- gear oil in it, and shifting. Believe the hydro-mechanical shift rod is opposite of regular mech lower units (down to shift into forward gear with your unit), when you inspect the l.u. and test it.

Think it's probably the powerhead. I've had success using ATF on a couple -- condition doesn't sound good, but no evidence so far of damage from overheating or similar (room for optimism). I'll go out on a limb and say it would be useful to fill the l.u. with ATF too while working on the powerhead. I think the oil pump would benefit.

[ed. check the manual for recommended l.u. oil for operation -- might be type C, but poss. reg hypoid. Not sure offhand.]

 

[Chrisravosa36]

I'll go out on a limb and say it would be useful to fill the l.u. with ATF too while working on the powerhead. I think the oil pump would benefit.

I dont think it could be overheating at all. It the powerhead on the outside is very clean, no black or brown areas. The lower unit seems to be fine, it will shift into forward and reverse, I can spin the prop about 1/2 way until it stops (normal) and neutral works fine. Dont get the manual till monday, but I will deff take a look at the lower unit when I get home today, Im hoping the impeller is still decent, because that would ensure it was just a hummitity issue.

 

[oldboat1]

Thanks. Would like to see what you find as you go. Good luck with it.

 

[racerone]

Type C oil is required for electric shift.---------This 1974 unit is NOT electric shift , so HY-VIS or similar oil is used.

 

[metriccrescentwrench]

.....Your lower unit on that motor is by far the most valuable part also the most expensive to fix. A lot of parts for those are NLA

I tend to agree. Those hydraulically assisted lower units were only made for a few years and from what I've seen are hard to find. If indeed there's a serious problem with the gearcase and you can't find a replacement it might be time to consider parting out the engine (for only having $50 into it you'll come out in good shape if that's the way you go).

 

[oldboat1]

have run the hydro-mech and a couple of electrics, but been years ago. Thinking failure of the pump (or at least partial failure) still allows the Powershift II to operate -- still a mechanical shift. But maybe not. I think clean oil might have been particularly important, but don't recall any issues with the one I had. Don't remember what I actually ran in it.

I think Premium Blend now substitutes for Hi-Vis -- don't know the viscosity. Think it's a blend for lower cold viscosity -- higher than the type C for the electrics, but probably a little lighter than the 80-90w normally used.

 

[Chrisravosa36]

no luck with the lower unit. Got all thee nuts and bolts off, just wouldn't budge, I opened up where the drive shaft would be, took some pics. I disconnected the shift and all the bolts.any tips?

 

[oldboat1]

couple of bolts underneath the a.v. plate, maybe under the trim tab?

 

[Chrisravosa36]

Got them all, even under the anode...wont even budge a little side to side. Might try to tip over the motor, and spray some PB or wd40 into the shaft connector to the head, see if that will work.

 

[oldboat1]

Might do some searches here on "stuck driveshafts" or "stuck lower unit", something similar. Just a general point -- keep a block of wood underneath in case it drops. The can be a little like a flywheel suddenly deciding to come loose after a bunch of prodding.