stuck lower unit -- 1989 8hp johnson

[mgilbert]

I removed the two upward facing bolts and most of the downward facing bolt (that bolt turns but does not back out) ... it seems like the lower unit is stuck. The manual does not list any disconnection of the shift linkage ... the manual does say to shift FWD ... but the reason that I am removing the lower unit is because the motor will not shift FWD. Thanks in advance. -Mike

 

[Chinewalker]

Re: stuck lower unit -- 1989 8hp johnson

Hi Mike,
The shift rod is a slide fit - nothing to undo. It is just those three bolts holding the unit on, so if it is not coming off, then...
A) the forward bolt that is just spinning is stripped, but corroded enough to not let loose its grip on the gear housing... Might have to cut the head off the bolt to allow it to pull through.
B) or the driveshaft is stuck in the powerhead (not uncommon on these little twins). Would need to pull the driveshaft out of the gearfoot (pulling the waterpump pin past the housing) and then pull the driveshaft out of the powerhead - hoping it didn't ruin the driveshaft splines.

 

[Vic.S]

Re: stuck lower unit -- 1989 8hp johnson

So long as you have removed the front bolt far enough for the threaded part to have come free that should not be a problem. (I'd guess from what you say it is not this bolt that is causing the problem)

I have no idea why they say engage fwd gear. Personally not bothered. The shift rod on these turns, unlike most which push and pull, and it should just pull out of the mechanism at the top.

Probably your drive shaft is stuck in the crankshaft. More force I think is the only solution but there is nothing holding it at the bottom and eventually it will pull from the gearcase but the water pump impeller key will damage the water pump housing or at least the cup.

If yours is a long shaft model take the extension off with the gearcase (undo the two upward facing bolts in the side of it) then remove it after cleaning the driveshaft. (reason being that until cleaned the driveshaft will not slide through the bush in the extension)

 

[mgilbert]

Re: stuck lower unit -- 1989 8hp johnson

Thanks for the advice ... here is some feedback ... I was able to separate the lower unit about another 1-inch ... it looks like the drive shaft is the part that is stuck. Unfortunately my use of a 2x6 with a 5lb single-jack caused a small crack in the ledge where I rested the end of the 2x6. My next plan is to build a wooden clamp that fits tightly to the outer countour of the lower unit ... to provide a more solid platform to pound against. I may just end up re-powering the boat since both motors are fairly old Johnson 2-strokes (1979 175 HP and a 1989 8 HP). -Mike

 

[Vic.S]

Re: stuck lower unit -- 1989 8hp johnson

I am surprised you have not managed to pull the drive shaft out of the gearcase at the expense of the waterpump! It is only the impeller key that is holding it in. There is no circlip on the bottom and it is not pinned to the pinion gear.

I pulled mine through the pump once although it did have a non OEM impeller fitted that had a plastic key. The key was destroyed but the pump was not badly damaged luckily.

 

[mgilbert]

Re: stuck lower unit -- 1989 8hp johnson

The lower unit finally came off with the help of a car-jack and a 5lb single jack, applying force against a wooden clamp around the lower unit. Now that the lower unit is removed, turning the shift-rod does appear to work properly in all settings ... FWD-NEUTRAL-REVERSE. The problem of not shifting into FWD must be somewhere in linkage to the shift handle. I plan to go ahead and service the water pump and maybe even try and remove the prop. Thanks again for the advice and support. -Mike

 

[Vic.S]

Re: stuck lower unit -- 1989 8hp johnson

Not a lot up at the top. You'll have to remove the powerhead to get at it. Removal of the LU was not wasted effort, you would have had to remove it anyway.

Unbolt the powerhead and rock it backwards and forward so break the joint (It won't rock from side to side)

Just two bevel gears, one on the shift lever shaft and one that the shift rod fits into.
View attachment 42080

(Sorry cut off the cover when I copied the diagram)

While you have the powerhead off inspect/replace the grommet at the top of the watertube (a bit of a recurring headache on slightly older models. '89 might be different though)

 

[mgilbert]

Re: stuck lower unit -- 1989 8hp johnson

I got the power head off without any problem.

Now I am replacing the water pump and noticed that the drive-shaft has a hex-nut stuck on it just below where the impeller should sit. I am guessing that this hex-nut is the inside of the old impeller and got pushed down the drive shaft when I used the car-jack to get the lower unit loose.

Can anyone confirm that metal inside the impeller looks like a hex-nut? If that is the case, then I'll probably try cutting it off the drive-shaft.

I am still not 100% sure I fixed anything to do with the shifting problem ... both ends seem ok ... and I doubt that I want to dig further into the gear-case.

Thanks
-Mike