lower unit removal 1984-? 25 HP Mercury

[outbdnut2]

Help!……I’m working on a 25 Merc for a friend. SN 6459102, which I think is 1984. It has the gearshift integrated into the tiller throttle. It needs a water pump impeller. To get the lower unit to drop, it appears I have to disconnect the shift linkage from the top of the shift rod that runs down to the lower unit. There is a screw (part 37 below) in a plastic bracket that I managed to get out with difficulty (I think someone lost the original screw and forced in something with a slightly different thread).

Do I now separate and remove that two-part black plastic parts (#35 and 36 below) with the pin that goes through the shift rod from the top of the rod to enable the lower unit to be pulled? or does that part stay on the rod and the linkage that locks the tilt function while in reverse get somehow moved out of the way and the black plastic parts on the top of the rod stay on it as it’s pulled through the housing to remove the lower unit? I’m wondering if that pin in parts 35 and 36 with the shift rod in between is a pressed interference fit that should not be disturbed?

or am I missing something here – is there some other procedure for freeing up the shift rod?

I’m talking about removing parts 35 and 36 at the bottom of the diagram below that clamp linkage to the shift rod so I can pull the lower unit. These parts are behind the carb:
Dave

[fisherman6]

Dave, I have an ’86 and it has been a few years ago when I did the water pump. If memory serves, I had to remove the screw #37 and separate #36 from #35. #35 remained in place on the shaft #34. With #36 removed the LU will drop. I remember having a bit of "fun" getting the shift rod routed properly and getting the linkage back together then getting the screw back in when it was time to reassemble it. I had to do it a couple times too. I either didn’t get the water tube in the pump housing right or I didn’t get the shift rod through the proper guide or something. In was VERY happy to have gotten it back together and working when I did. It isn’t the most fun motor I have to work on. It is a screamer though. Someone else may have a better explanation, but I hope this helps.
-Ben

OldJohnnyRude on YouTube

[outbdnut2]

Hey Ben, Thanks for the reply! I looked at it again this morning and was about to post my follow up here below when you posted. Yes – you are remembering it right!

Ok, I got it! – I futzed with it a bit more after finding the exploded view in my original post above and found that parts 35 and 36 pried apart with a screwdriver without much effort once screw 37 was backed almost all the way out and then those parts separated from the shift rod once the pin in part 36 was not in the top of the shift rod anymore, and now the lower unit pulls out. Working in tight quarters , it’s going to be a bit f a challenge to get this back together. I had to pull parts 36 and 37 out with a elongated curved needlenose pliers, while keeping them from dropping down in the housing.

I also learned that this area was redesigned within the next few years to have a clip that pulls off to release the shift rod instead of these parts and the screw. They must have had a lot of complaints about these parts!

I’m going to replace screw 37 with one that is either hex head or allen-head to make it a lot easier to put back together.

Hopefully someone else here can benefit from my experience now.
Dave

[jeff-register]

YEP! Sounds like a Merc!

[dockbuster1]

When you put the lower unit back on make shure the washer is on top of the bumps on the shaft and get it thru the loop of wire that operates the reverse locks other wise the engine will stay locked down in foward

[fisherman6]

Dave, I thought I still had a pretty good recollection of that nightmarish arrangement. A stainless socket head screw to replace the one that’s in there would make it easier. It is very tight in there. I’m sure the clip made.it easier to deal with in later years. I’m glad the impellers on these seem to last quite a while. Replacing it again is not a job I look forward to. I used all sorts of magnets and pliers and whatnot to get that screw back in.
-Ben

OldJohnnyRude on YouTube

[outbdnut2]

quote Callie30R:

When you put the lower unit back on make sure the washer is on top of the bumps on the shaft and get it thru the loop of wire that operates the reverse locks other wise the engine will stay locked down in foward

That washer is missing. Parts 36 and 37 directly ride on top of that reverse lock actuator wire…..but thanks for the reminder that there should be a washer there – I’ll find a suitable stainless one. A previous owner must have lost it. I see Sierra makes that washer.
Dave

[outbdnut2]

quote Fisherman6:

Dave, I thought I still had a pretty good recollection of that nightmarish arrangement. A stainless socket head screw to replace the one that’s in there would make it easier. It is very tight in there. I’m sure the clip made.it easier to deal with in later years. I’m glad the impellers on these seem to last quite a while. Replacing it again is not a job I look forward to. I used all sorts of magnets and pliers and whatnot to get that screw back in.
-Ben

Yes – I’ve already checked and the screw appears to be a 4 mm metric that’s 3/4 inch long – I’m going to get a hex or allen head for it. i don’t know if it’s always been really tight ir if the plastic it threads into shrunk slightly over time tightening it’s grip on the screw.

I pried the plastic parts the screw goes into off the metal shaft they pivot on with the screw backed out almost all the way, but still with the pin through the shift rod – I think I can start the new screw in those parts a couple turns before I put them in the motor and then put together in reverse order of my disassembly so I do’n risk losing the screw. I just have to watch I don’t drop parts 36, 37, and the screw down the housing.

Dave

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