Bent upper shift shaft - easy fix? 1999 40 HP EO

[rstier]

Hi,
My older 1986 35 Merc finally died (splines on crankshaft to driveshaft connection worn) and I'm in the market for a replacement. I found a 1999 Merc 40 EO on Craigslist and went to check it out. Compression was good, it started and idled fine. The lower unit and oil looked good, overall it appeared to be in great shape. Unfortunately, it wouldn't go into reverse. I could see the upper shift shaft was bent at the coupler, where it connects to the lower shift shaft. Due to the bend, it was preventing the shift shaft rod from moving down into the lower. At that point, I decided to pass. Can someone tell me if this is a difficult fix? Does the power head need to be removed or can you replace the upper shift shaft without removing the power head? It looks like you'd have to remove at least 1 carb.
Thanks in advance!
Ron
PS...I attached a pic of the shaft I am referring to with an arrow where the bend is.

 

[Scott Danforth]

buy a new gasket, pull power head, pull shaft, put in vise, smack with hammer until straight, reinstall

I bent the upper shift shaft on a 9.8 by just pulling the power head because it was stuck in the bottom of the power head when I lifted up and over. 300 series stainless is soft/gummy/stuff

 

[rstier]

No Title

Thanks Scott. I just checked the parts diagram for this particular motor again and noticed there is a pin and cotter pin holding the upper shift shaft in place. I attached an updated diagram to show what I meant. Could that pin just be pulled off and the shaft would drop out the bottom if the lower housing was removed? I just wanted to confirm that the power head did indeed need to be pulled for this particular year/model. Pulling the power head on this one seems like it would be a big pain in the butt due to the weight of the motor. On a 9.8, not so much.
Thanks!

 

[thomas15]

I just replaced the upper shift shaft and the horizontal shift shaft on my 2005 50 HP ELPTO 2 cycle. The diagram you show is exactly like mine.

When I tried to uncouple the upper shift shaft from the lower to remove the lower unit to replace the water pump, I managed to break both of those shift shafts. So I ordered the parts and plotted the fix. To get at where the pin and cotter pin are I didn't have to remove the power head but I did have to remove all 3 carbs. That gave me room to wiggle the shaft in and pin and place the cotter pin on the pin but it took quite a bit of time to tease everything in. I don't think it could be done with the lower unit still attached, there would be no way to feed it up to the power head. So I guess it's either the carbs and lower unit or the powerhead. Since I needed the lower unit off that was how I decided to proceed. A lot of work just to replace the impeller. Obviously I had to get new carb gaskets also.

The PO I believe cross-threaded the adjuster nut that I needed to remove to separate the upper and lower vertical shift shafts. Somehow the threads were damaged. When I compared the new shaft to the old the old was about a half inch too short. I tried everything to get them to separate, soaking in penetrating oil, PB Blaster and heat. Finally it snapped and the adjuster nut I believe went into low earth orbit and hasn't been seen since. Obviously the adjuster nut took some of the shift shaft with it.

 

[rstier]

Thanks for the extra info! That doesn't sound like a fun project, I hope all worked out well. So it sounds like it can be done without pulling the power head.

I just replaced the upper shift shaft and the horizontal shift shaft on my 2005 50 HP ELPTO 2 cycle. The diagram you show is exactly like mine.

When I tried to uncouple the upper shift shaft from the lower to remove the lower unit to replace the water pump, I managed to break both of those shift shafts. So I ordered the parts and plotted the fix. To get at where the pin and cotter pin are I didn't have to remove the power head but I did have to remove all 3 carbs. That gave me room to wiggle the shaft in and pin and place the cotter pin on the pin but it took quite a bit of time to tease everything in. I don't think it could be done with the lower unit still attached, there would be no way to feed it up to the power head. So I guess it's either the carbs and lower unit or the powerhead. Since I needed the lower unit off that was how I decided to proceed. A lot of work just to replace the impeller. Obviously I had to get new carb gaskets also.

The PO I believe cross-threaded the adjuster nut that I needed to remove to separate the upper and lower vertical shift shafts. Somehow the threads were damaged. When I compared the new shaft to the old the old was about a half inch too short. I tried everything to get them to separate, soaking in penetrating oil, PB Blaster and heat. Finally it snapped and the adjuster nut I believe went into low earth orbit and hasn't been seen since. Obviously the adjuster nut took some of the shift shaft with it.

 

[thomas15]

Yes it's all back together and I had it out on the water yesterday. Ran well. One good thing about the experience is that I know a few things now that I didn't know before I started this project. Slowly the mysteries of this motor are becoming understandable.

Before I started this I was told by several who work on these motors that taking the powerhead is the way to go and the factory service manual tells you exactly how to do it. But again since I already had the lower unit off I went the route I spoke of. I don't know how much the powerhead weighs but the manual suggests using a lifting eye and hoist.

Hopefully yours will go well and your back on the water soon.