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2011 BF90D RH rotation vs. LH rotation?

A

Alan Hicks

Advanced Contributor
Guys, I bought a "fixer upper" engine that required the lower unit be gone through. I installed all new seals, prop shaft needle bearings and the upper drive shaft bearing. Point being, I pretty much had this lower completely disassembled.

Everything back together, I test fire it and all is good - except it's going to require a LH prop. The prop shaft is turning the opposite direction than what I expected.

The question is, for you pro's out there, is there something I could have installed incorrectly that's now haunting me with reverse rotation, or did I manage to buy a LH engine/lower unit?

Bonus question- what exactly, is the difference between a RH lower unit and a LH on this motor? Is this one of those lowers where the forward and reverse gears are swapped and the clutch dog flipped? If so, then what? Where is the difference in the shift mechanism that reverses the direction of the shift (LH vs. RH)?

Thanks for any help or direction. It would be much appreciated. -Al
 
This issue is making me crazy, so I've been pondering on it a bit and I think I may have found the source of my headache - a screw up on my part during reassembly. See if this makes any sense-

https://www.boats.net/catalog/honda/outboard/90hp/bf90a6-lrta-2006/water-pump-vertical-shaft

https://www.boats.net/catalog/honda/outboard/90hp/bf90a6-lrta-2006/propeller-shaft-propeller

In the first drawing, reference part #10, and in particular, the offset of the pin on the bottom of it. That pin fits in a groove on the "shift slider" shown as part #4 in the second diagram (grove shown directly above the "4").

Now, I'm pretty sure that the prop direction can be reversed if that "shift shaft" (#10 in the first drawing) were lifted up and turned 180 degrees so that bottom pin is moved to the OPPOSITE side of the shift slider (as compared to it's current position).

Thoughts?

Normally I would just go ahead and make the change to try it for myself, but this motor has been sold, and it's new owner is a couple hundred miles from here, so messing with it on my own isn't possible. Not a serious repair if my thought is correct. With some direction, he's capable of taking care of this himself I believe.
 
Well, I don't know myself but this isn't the first time this "issue" has been discussed on this forum.

Check out this "blast from the past":

http://www.marineengine.com/boat-forum/showthread.php?386743-rotation-change

Read hondadude's comments in particular.

It sure makes it sound, at least to me that the pin (or cam) at the bottom of of the lower shift shaft can be poitioned on the wrong side of the slider and cause the transmission to rotate in the wrong direction just as you say.

Good luck.
 
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