1980 Mariner 6ycl 90HP stuck in forward after lower unit R&R

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Removed lower unit for impeller service. Put shifter in Forward first. When checking the shifting after putting lower back on the prop movement is the same no matter where the lever is. Ratchets when spun clockwise and locks up trying to go counterclockwise like it is still in forward. Normal operation is ratcheting in forward or reverse depending on which way you move the prop, and free spin in neutral.

I pulled it off again to try to check the lower unit shifting by itself. No matter what way I turn the shifting rod I get no shifting action. Most of the time the rod can spin freely left and right lock to lock, seem to be about 270 degrees movement. Sometime it won't move after I have moved the prop, then it frees up again when it ratchets. When the prop ratchets the rod moves some when you hold it then kind of snaps back.

First question is how can I make the lower unit shift now to check the mechanism Then if it is really Ok and I am just ignorant of the action, how can I get it lined back up correctly when installing.

The Upper unit shift rod coupler does not move much at all when I watch it while someone moves the lever. Kind hard for me to understand what all is going on with this setup.

Engine model year is 1979 1/2 90hp inline 6 Mariner , s/n 5310218

Thanks!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,035
Turn the shift rod CCW until it stops. The gearbox should be in forward (rachets CW). Now use a small cresent wrench to turn the shift lever a bit more CCW, until it "clicks" into neutral. Set the control to neutral, and reinstall the gearcase. Turn the flywheel to mate the driveshaft to the crankshaft.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Thanks Chris, much appreciated. Not sure what I did to make that shaft move out of range, tried not to move anything. I did turn the driveshaft while maneuvering the pump housing over the impeller.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
The shift shaft rotates a 'cam' with indents in two places to indicate Neutral and Reverse. Inside the prop shaft is a spring that pushes the shift slider into Forward gear if the cam is not in either of the detents holding against the spring. If the shaft had been 'bumped' too hard it moved enough so when you raised the LU the shaft was not indexed correctly. No big deal, it happens a LOT.

Drop the LU again, Index the shaft as Chris described and be done.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Thanks! Helps me to understand what is going on, and how I caused my alignment problem.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Got it done! Thanks Chris and Charlie.

I got the gearcase into neutral per Chris's instructions.
I took all the spark plugs out so I could turn the flywheel easily. I was replacing them anyway as part of this year's maintenance.
I put the lever in neutral.
I inserted the lower unit (I had already changed the oil and installed new impeller, pump housing looked great).
Got the water tube aligned then pushed it up a little further,
On this one you need to push the speedometer pitot feed tube onto the fitting in the front of the housing just before you align the driveshaft and shift rod coupler.
The driveshaft hits just before the shifter coupler, so I turned the motor just enough until the unit moved up just enough to feel the driveshaft start.
Then aligned the shift coupler in the main housing over the shift rod in the lower.
I had the skeg on the ground at this point with some pressure on it by raising the jack.
I went to the lever and moved it slightly into Forward and CLUNK the coupler and shift rod aligned.
I worked the lever and verified at the propshaft that I had Forward, Neutral and Reverse by checking the ratcheting and free-wheeling, all good.
I actually had to let the lower down just a bit at this point to get those first two nuts on at the front.
Buttoned it all up, put the plugs in, hooked up the water and started it up.
The pee-hole water started just a few seconds later, good solid stream. The old impeller was intact but had taken a set and the edges were very glossy and stiff, and the pee-water stream had started to take a while to show up and was not always a solid stream at low rpm's.
It also idled much better with the new plugs.
Can't wait to get it back on the water.

Is iBoats a great community great or what :rockon:
 
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