Forward Gear and Prop Shaft

[cjs1984]

Hi, I have a 1988 Force 125 outboard and I have a question... The forward gear on the prop shaft wobbles about 1/16 the mechanic at boat shop recommends buying a new lower unit and swapping prop shaft/gears. I have no problem with that but my question is, what if I just have him install the old prop shaft/forward gear with the wobbling and just use the boat 'til it goes out... Is there any dangers involved besides just being stuck on the water and replacing the lower unit then? Any insight greatly appreciated. Thank You!
No I hear you and am not looking to pass liability upon another person.. The jift of the story is last year clutch dog went out they wanted alot of money just to replace it so I did it myself, it worked for a day but when I took it home to flush engine I heard a rattle so I took it apart again and when I put it back together it bent the shift shaft, I decided to let a professional do it and with everything replaced/labor it was 400$ and after he had parts and took entire unit apart showed me that since the forward gear was wobbling (not in and out or forward to back altogether) if you pushed top forward bottom wobbled backward etc.. He said due to that, that is what made my old clutch dog go bad and I should replace it, he said he had a used lower unit and yes shim it correctly but double the cost it was in first place. And with my luck if I spend 800 bucks on lower unit who's to say the top end of motor wont go bad, I haven't used the boat that much seems every time I take it out something else is wrong with it, that's why I just want to beat it up til it needs replaced or beat it up til it blows up and move on.

 

[Frank Acampora]

I'm not sure I understand correctly so I will describe two scenarios. However, I do question what complaint you had to require dis-assembly of the lower unit.

The forward drive gear is carried on a tapered roller bearing. Although it should have a bushing to ride on the prop shaft, it is not necessary although it will rattle a bit in neutral and reverse. In forward, the prop shaft thrusts against the gear hub and all forward thrust is delivered through the bearing to the gear case casting

HOWEVER. The bushing is a standard bronze bushing which can be purchased at any bearing supply store. It is a PIA to replace because you must completely dis-assemble the lower unit to remove the forward gear and press in a new bushing.

Now, the reverse gear is carried in a needle bearing and there is a gap between the gear hub and the prop shaft. This will wobbly on the shaft when removed from the gear case. This is normal.

As I explained in the previous reply, it is not really a good idea to swap gears and shafts into another case unless you have the shims and tools to set gear backlash.

NOW, if the forward gear and bearing is moving in the casting itself, then yes, it is time to get a good used lower unit. If it does fail, it will be catastrophic. You very likely will lock up the lower unit and you might just possibly lose the prop shaft, gears, and prop. Better not to get stuck on the water unless you are within paddling distance of the ramp.

 

[alldodge]

Hi, I have a 1988 Force 125 outboard and I have a question... The forward gear on the prop shaft wobbles about 1/16 the mechanic at boat shop recommends buying a new lower unit and swapping prop shaft/gears. I have no problem with that but my question is, what if I just have him install the old prop shaft/forward gear with the wobbling and just use the boat 'til it goes out... Is there any dangers involved besides just being stuck on the water and replacing the lower unit then? Any insight greatly appreciated. Thank You!

:welcome: to iboats

I think this is a Vegas question and rolling the dice. You can run your current drive until the lower unit seizes up. If nothing else is broke when it sizes, your good. Get towed in and then replace the lower unit. IMO I don't see things coming unglued and the engine coming apart, but we are rolling the dice and I don't gamble with these issues. The last thing I want to do is explain why someone got hurt because I didn't think nothing dangerous would happen.

 

[cjs1984]

No I hear you and am not looking to pass liability upon another person.. The jift of the story is last year clutch dog went out they wanted alot of money just to replace it so I did it myself, it worked for a day but when I took it home to flush engine I heard a rattle so I took it apart again and when I put it back together it bent the shift shaft, I decided to let a professional do it and with everything replaced/labor it was 400$ and after he had parts and took entire unit apart showed me that since the forward gear was wobbling (not in and out or forward to back altogether) if you pushed top forward bottom wobbled backward etc.. He said due to that, that is what made my old clutch dog go bad and I should replace it, he said he had a used lower unit and yes shim it correctly but double the cost it was in first place. And with my luck if I spend 800 bucks on lower unit who's to say the top end of motor wont go bad, I haven't used the boat that much seems every time I take it out something else is wrong with it, that's why I just want to beat it up til it needs replaced or beat it up til it blows up and move on. And I don't mean explode on the water, lol.

 

[jerryjerry05]

Get another lower.
They're out there.
No fuss No muss!