175hp drive shaft splines seem stripped. Crankcase too?

[johnk86]

I have a 1988 175hp Johnson Outboard on my boat. I was fishing a couple of weeks ago and when I was returning, I powered up the throttle and a moment later, something "gave" and the motor raced and I had no power to the prop. I turned off the motor, started it again, but again, not power to the prop when moving between forward and reverse. I did some quick troubleshooting to see if a cable gave way but it hadn't. Being 12 miles from dock, we ended up having to be towed in by the Coast Guard. Not a great day. Anyway, sensing that the problem may be big and considering it is "offseason", I pulled the lower unit off myself, quite an ambitious undertaking for me. Anyway, after removing it, I thought I would find a broken drive shaft. But instead, its in tact but the splines at the top appear, well, kinda stripped. They aren't flat, but not very raised and a neighbor said they looked stripped. They also have some built up dirt in between what is there of the splines that I had to scrape with a knife to get out. Not what I expected from a connection like this. So, does anyone have a gut reaction? I have not checked the crankshaft splines because I'm not ambitious enough to take off the powerhead. Also, I don't have the right tools to disassemble the lower unit and remove the drive shaft. I'm trying to see if, from experience and what I've described, I'm looking at a "big problem" or a "smaller problem". If/when I take it into a repair shop, I would like some idea of what I should expect. Thanks for any help.

 

[Dhadley]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

A couple of things to look at. First, I'm wondering if the hub in the prop hasnt spun. Did you try your spare prop? Second and very important, was the motor still pumping water even though it would not go into gear? <br /><br />If the splines only look "worn" there may be some attention needed in that area. Whatever the driveshaft splines look like most likely the crank splines look similar. <br /><br />Manually shift it now and turn the d/shaft by hand and let us know if it turns the propshaft. What does the l/unit oil look like?<br /><br />Good luck!

 

[Dhadley]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

Oh -- and welcome aboard the board!

 

[R.Johnson]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

Have you hit an obstruction with this engine? Your problem sounds like a sprung exhuast housing. A sprung exhuast housing will stress the upper splines. A sprung gearcase will stress the lower splines where the drive shaft goes into the pinion gear. Unless this engine is run with a surfaceing prop, anything but damage to exhaust housing, or gearcase is unlikely. A fast running boat with a surfaceing prop can leave the water and come down, making the prop hook up with a good deal of force to the crank, and drive shaft.If you hit an upstuction, don't replace the drive shaft, the problem will not go away.

 

[johnk86]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

Thank you so much for the quick replies and suggestions. I don't know if the water pump impeller was spitting water when I lost propeller power. I did go out to the garage and manually shift the lower unit into forward and reverse and was able to turn the drive shaft by hand make the propeller go in both forwards and reverse. Does that narrow it down to the splines on the drive shaft and crank shaft or something else to do with the connection at that point (e.g. they "came apart" for some reason?), or could the gearbox still be a problem even though I can turn it. Thanks for your help. <br /><br />PS: I'm still hesitating packing it up and taking it to the shop because if the powerhead needs to be removed, the splines on both ends need to be reworked, and the lower unit needs to be disassembled, I fear it will be a big enough cost for a repair for that old and engine that it may warrent looking for another used engine. Let me know if you think my thinking is wrong.<br /><br />PPS: I do have a shop manual for it; that's how I discovered that I don't have the right tools to disassemble the lower unit (e.g. propeller wrench, snap-ring puller, etc).

 

[johnk86]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

One more note: I was out in the middle of the Chesapeake Bay and don't remember hitting anything. I got the engine used so it may have incurred some damage before I got it (I got it two years ago) but I've put a number of hours on it since then with, seemingly, no problem of this nature (e.g if it was slipping, I didn't notice it)

 

[Dhadley]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

What about your spare prop? Did it do the same thing?

 

[johnk86]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

Alright, I'm embarassed to admit that I don't have a spare prop. And I don't have a wrench big enough to take off the nut holding on the propeller. If you would please, can you let me know your thinking on how that will make a difference? I just don't understand. If I put another propeller on, turn the drive shaft and it turns, then both turn and what would that tell me? I really appreciate the help, just trying to understand. Thanks!

 

[Dhadley]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

If the hub in the prop was spun -- completely -- you would have no thrust. But the water pump should still be working. IE -- if the water pump was still working then the "disconnect" would be from below the pump out to the prop. <br /><br />The other side of that thought is that if the pump was not working then the "disconnect" would be from the pump up. And the splines would be suspect, as you mentioned.<br /><br />Take a flashlight and look up into the mid section and just see if you can see splines in the bottom of the crank. Much easier at night.<br /><br />Since you can manually shift it and it works, we can most likely reason out something like the shaft sheared below the pump.

 

[G DANE]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

Hi<br />Ruining the splines is quite rare. I'd put my money on your prop. Try to remove the prop and look at the hub from the exhaust side. ( motor side ) You can see a rubber hub between the inner bushing and hub housing. In most cases where a prop is spun, you can see the rubber is damaged, ripped apart. ( however sometimes not ) Take a look and post back. Sometimes the prop will slip, when in water and not dry. Were you able to turn motor by the prop, when in gear ? ( IGNITION OFF )

 

[johnk86]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

Hi, me again. I did not remove the prop but I did move the prop and it moved the drive shaft and vice-versa. I even tried to hold the drive shaft still while I turned the propeller and I couldn't hold it. I know its not a definitive test, I will remove the propeller as soon as I get a big enough socket. In the meantime, a neighbor came and looked at the splines on the top of the driveshaft and, like the two who looked at it before, thought the splines looked "stripped". That is if the splines in the powerhead were in the same condition as these, there would be no real connection. The top of the splines looked abnormally "flattened". Anyway, hypothetically, if the splines are the problem, and the splines in the crankshaft are in similar condition, does that mean the crankshaft itself would have to be removed and reworked, or is there a connecting mechanism between the crankshaft and the driveshaft that would "give" before the crankshaft would be damaged? It would seem to make a big difference in cost of repair. The shop manual is not clear on the the connection except to say "inspect splines" when removing the drive shaft. Any insight you could give would be appreciated. And I'll let you know when I get the prop off. Thanks!

 

[Solittle]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

hokie - Hope that your problem turns out to be something else but if the splines are stripped your homework assignment is:<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=002874 <br /><br />There may be others - check the red search at the top of the page - I put in drive shaft but try others as well.<br /><br />Howard

 

[johnk86]

Re: 175hp drive shaft splines seem stripped. Crankcase too?

Well, I loaded up the lower unit and took it to a local marine repair shop that specializes in Johnson outboards. The lead mechanic that worked on my boat last year (did a tune up, water pump change) looked at the splines and said they were stripped. He said the crankcase side was probably worse. He said "that's bad. one of the worse things that can happen to an engine". He estimated about $3,000 to repair. He said on a 1988 engine it probably wouldn't be worth it. I saw the thread on the forum where someone put a drive shaft in an oven and repaired it. I wouldn't want to do anything non-traditional like that fearing a short term fix instead of a long term fix. Time to start looking for a new engine? Thanks for your help.