How do you shift a mercruiser lower unit (not attached) into forward?

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Somehow, I believe, my lower unit shifted into neutral and I'm having trouble bolting it on. Get the splines lined up, slide it in just enough so I could almost start screwing on the nuts, and it will push in no further. No obstructions noted.
Or, is there another possible cause as to why it won't just slide on and in? Best advice I got so far was that it sounds like the lower unit is in neutral. Prop spins forward, but not reverse.


Any way/ techinque to shift the detached lower unit into forward without dropping the foot?
1985 Mercruiser 3.0 L, 130 hp.

thanks for any suggestions
 

z1nonlyone

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Re: How do you shift a mercruiser lower unit (not attached) into forward?

Make damn sure the shift fork is lining up in the slot!!! you can shift the outdrive by turning the shift shaft by hand while turning the prop. The tab on the shift fork needs to fit in the groove of the shifting mechanism,,,,,VERY IMPORTANT!
 

dollarten

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Re: How do you shift a mercruiser lower unit (not attached) into forward?

Another way to keep it in forward is to pull up on the prop while you are putting the drive unit back on . Sounds awkward at first but this will keep tension on the shifter clutch so it will stay in forward have a helper . Then while have tension on the prop shaft you can pull up a little more in order to line the splines up when the drive shaft meets the engine i
 

stonyloam

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Re: How do you shift a mercruiser lower unit (not attached) into forward?

To shift the lower into forward, turn the lower shift shaft (short splined shaft) all the way clockwise, turn the prop counterclockwise till it locks, then use a bungee on the prop to hold it in place. The intermediate shift shaft slides onto the lower ss and should be pointed straight ahead to match the bottom of the upper ss (control handle WOT forward). If you need to turn the driveshaft in the lower to slip into the upper turn CCW only.

"Prop spins forward (clockwise), but not reverse (counterclockwise)" as it should when you are in forward.
 

stonyloam

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Re: How do you shift a mercruiser lower unit (not attached) into forward?

Somehow, I believe, my lower unit shifted into neutral.....

Am a little confused here. By lower unit do you mean the entire outdrive or just the lower half of the outdrive. Usually the gearcase (lower half of outdrive) is referred to as the lower unit.
 
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Re: How do you shift a mercruiser lower unit (not attached) into forward?

I mean the entire outdrive. My mistake.
 
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Re: How do you shift a mercruiser lower unit (not attached) into forward?

I'll have to drop the foot of the outdrive to get at the shift shaft, right?
I have the entire outdrive intact right now; I haven't dropped the lower unit .
I'm no expert with merc outdrives, but is there a method to shift into forward with the entire outdrive intact?
 

stonyloam

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Re: How do you shift a mercruiser lower unit (not attached) into forward?

I'll have to drop the foot of the outdrive to get at the shift shaft, right?
I have the entire outdrive intact right now; I haven't dropped the lower unit .
I'm no expert with merc outdrives, but is there a method to shift into forward with the entire outdrive intact?

You do not. Just locate the intermediate shift shaft sticking up out of the driveshaft housing on the outdrive and turn it all the way clockwise. Turn the prop counterclockwise till it locks, and bungee it in place. You are now in forward. The top of the intermediate ss should be pointed straight ahead, as is the bottom of the upper ss in the bell housing. The i ss slides into the u ss when you put the outdrive on. Make sure the control handle is WOT forward. Here is an illustration of the parts: http://www.mercruiserparts.com/Show...0065.png&inbr=2203&bnbr=60&bdesc=BELL+HOUSING #21 upper ss, #22 intermediate ss.
 

kckranz

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I realize this is an old thread but provides context to my question, so I don't want to start a new thread. I followed the instructions above to re-attach my lower unit MC-1 (GM 165) and can get it attached and bolted together but the problem I have is that the throttle / shifter in the cab doesn't "agree" with the prop in forward gear. Once everything is together (my throttle in FWD), I pull back towards neutral and it gets really hard to rotate (like it is about to grind or break something). Something isn't right. The one thing I notice on my second and subsequent attempts to connect the lower to upper is that the shift shaft splined "receiver" - the metal pipe that sticks down to mate with the shift shaft allows for rotation and some push up and down prior to mating. I feel like this needs to be set specifically to receive the spline shaft in order to sync with onboard controls. Any thoughts on this? Prior to disassembly, the shifter worked fine. PS - separated upper from lower to replace impeller.
 

Bt Doctur

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Remove the drive and split the unit.
place lower unit in some type of stand and turn the splined shaft fully clockwise while turning the prop CCW untill locked. This is Fwd
Lower the upper unit making sure the upper shaft locates on the splined shaft in a straight line, this is Fwd.
Install nuts and fill with oil
 

kckranz

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I figured out the missing piece of information (from my perspective). The brass "tube" that hangs DOWN from the upper unit and mates with the spline shaft is the intermediate shaft and has a KEY (or tab) at the TOP. You can visually inspect it's position above the lower unit to upper unit bolt that is closest to the transom. Once the prop is locked and HELD, spline is rotated CW and control is WOT forward gear, as you raise the lower unit into the upper you need to confirm BOTH the prop shaft splines line up AND the intermediate shaft tab / key faces the transom as it mates with the splined shaft. Looking up from the ground, you will see that tab / key enter the linkage above it the same way a flathead screwdriver lines up with a slotted screw.

My internal control lever now functions correctly.
 

GA_Boater

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I realize this is an old thread but provides context to my question, so I don't want to start a new thread. I followed the instructions above to re-attach my lower unit MC-1 (GM 165) and can get it attached and bolted together but the problem I have is that the throttle / shifter in the cab doesn't "agree" with the prop in forward gear. Once everything is together (my throttle in FWD), I pull back towards neutral and it gets really hard to rotate (like it is about to grind or break something). Something isn't right. The one thing I notice on my second and subsequent attempts to connect the lower to upper is that the shift shaft splined "receiver" - the metal pipe that sticks down to mate with the shift shaft allows for rotation and some push up and down prior to mating. I feel like this needs to be set specifically to receive the spline shaft in order to sync with onboard controls. Any thoughts on this? Prior to disassembly, the shifter worked fine. PS - separated upper from lower to replace impeller.

Yes, start a new thread. It's how we do it here and What the Help Tip on top of the page says.

Closed.
 
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