90 HP Merc 4-stroke driveshaft replacement

[Georooney]

I pulled the lower gear housing to rebuild the water pump, and got a nasty surprise. There was a bronze bushing stuck on the driveshaft, about halfway up. It doesn't appear in my drawings for the motor, so suspect it may be something that's used only with long leg motors? (Not sure I've got the terminology right, bu hope you know what I mean.)

After applying lots of penetrating oil and a bit of heat, I was able to tap the bushing down off the shoulder on the shaft and remove it. The face on the shaft is scored, so I suspect I'm looking at a new driveshaft? Also, the bushing is toast so will need a new bushing too.

What about the lower housing? (Not the gear housing; the housing below the powerhead.) The bushing has been spinning in the housing, so most likely damage there too. Is there a way to repair it? Or am I looking at a new housing?

Whatever else, I'm sure it's going to be lots of money. BOAT......Bring On Another Thousand!! :facepalm:

I'd appreciate hearing from those that have had similar problems, or just advice in general.


Thanks in advance,

​Geo

 

[Georooney]

PS: what happens if I choose to put it back together without the bushing? Will it fly apart on me? It's been running that way now for I don't know how long now, with no ill effects.

 

[Georooney]

Any opinions, comments or advice? :sleeping:

 

[Georooney]

Okay, here's my latest plan. (Why does it feel like I'm talking to myself?

) Clean up the bearing surface on the driveshaft, replace the bushing, and put her back together.

Sound like a plan? What could go wrong? Well, the shaft may be too small after removing the scoring. If so,I will have an undersized bushing machined. (I can do a lot of machining for the $600 price of a new driveshaft.)

It may not be like new, but it will be new enough for me.

 

[roscoe]

Well, 31 people have read the thread, and had no advice for you.
That is a bit discouraging, but unless a Merc tech has read it, likely no one knows or has any input for you.

Most people have not worked on a newer larger 4 stroke. I know I haven't.

What year and model number is your motor?

 

[Georooney]

Hi Roscoe,

Thanks for the words of consolation.

Motor is a 2002 90 HP Mercury 4-stroke outboard, serial OT446238.

No reply from the local Mercury dealer, but I have a line on a retired shipwright and a boat builder, both local and with machine shop facilities. I'm hoping one of them will be able to machine the shaft and make a new bushing. But first I need to remove the cowl from the gear housing, and inspect it to see if it's damaged by the bushing turning in it.

I've been away, but hope to get at it this week.

 

[Georooney]

Update: I got the plastic cowl off the drive housing, and managed to get the bushing retainer (a rubber sleeve) out. Next, I'll clean up the inside of the drive housing and get ready to drive the new bushing in when it arrives (ordered it yesterday).

My neighbour, the shipwright, will help me polish up the drive shaft surface where it was scored. Once that's done, i'll rebuild the water pump (the project that started this whole gong show) and put everything back together, fire her up and see if it runs.

I'm feeling relieved that a job I first thought was going to cost over $1,000 will only be the price of the bushing; under $100. Nice when you can do the work yourself, with a little help from your friends.