'72 45HP Chrysler - no forward gear!

[kauboy]

I took my dad's boat out to the lake today.
This is the same boat that I tried an impeller change on about two weeks ago.
We get out on the water, set it in neutral, and fire it up.
I get just off the trailer, and I kick it into reverse.
It backs up beautifully.
I move the throttle up through neutral and into forward....
and go nowhere.
I realize I don't have a forward gear.
My buddy and I could easily tell when the reverse gear would engage, but when we tried forward, we got nothing.
It would just rev the engine, and we'd stay put. I assume this was just neutral.
We tried many times.

I have two potential possibilities for why this is happening, but wanted some more knowledgeable opinions.
They both have to do with that impeller change.

Firstly, to drop the lower unit, we had to disengage the shift linkage.
Not knowing for sure where that was, we took off the four bolts at the cav plate and dropped it a little ways.
Inside, I could see a coupling with two nuts, one long, and one short.
I tried fenagling them to no avail. I set them back to where they were when we started, and we pushed it all back in.
Later we discovered that the disconnect was up higher in the housing.
After checking the impeller, we reconnected the linkage, and set the nuts back to their original positions... we think. We all agreed they looked right.
Could we have these two locations set off just a bit, and that keep forward gear from engaging?

OR...

After disconnecting the linkage and dropping the lower unit, we were holding the unit and checking the water pump.
My buddy, after being asked not to, pulled up on the driveshaft.
It moved...
I looked at him and said "Dude, put that right back. If you messed up my gears, I'm not gonna be very happy."
I had already told him not to pull on it.
He set it back as gently as he could, and it we checked to see if turning it clockwise would turn the prop. It did, and we went on with the assumption that it was okay.
(I didn't think to check to see if the prop spun in reverse, or forward. My mistake)

This seems to be the more likely cause of the loss of forward.
What do you guys think?
Could it be something I haven't even considered?

How hard is it to disassemble the LU and reset the gears?
Special tools?
Pay a mechanic?

Thanks guys!

 

[Frank Acampora]

Re: '72 45HP Chrysler - no forward gear!

The drive shaft is splined to the drive pinion and the only thing that holds it into the gearcase is the drive pin on the water pump impeller. You can pull it all the way out and slide it back and no harm will be done. If you did not push it in far enough, One: you would not be able to bolt on the lower unit, and two: neither gear would engage. (actually, both gears are always engaged and turning while the engine is running. A special dog clutch slides to mate with the correct gear you choose.

Since forward gear is downward movement on the gear linkage, it is more likely that you adjusted the linkage too short. That would cause no engagement in forward position, and you may get a rattle in neutral. Reverse will engage quickly and positively.

A little movement goes a long way: Remember, there is only about 1/4 inch travel each direction. So, try to adjust the coupler a half turn at a time in the lengthening direction until you ger positive engagement of both gears in the driveway. (engine does not need to be running)

 

[kauboy]

Re: '72 45HP Chrysler - no forward gear!

Thanks for the response Frank!
That will be much easier to correct, and I get to keep a friend, haha.

When I test this, what am I looking for to know it's working, assuming I don't need to run the engine?
Will I hear it engage?
Or do I need to set it, and then turn the flywheel?
Probably better to do the second, even if the first works.

I'll be ecstatic if it's just the linkage!!!
Too bad I didn't know this while on the lake, could have had it fixed in 15 min and been back on the water.
Oh well.

Thanks again!

 

[Frank Acampora]

Re: '72 45HP Chrysler - no forward gear!

You don't need to run the engine.Make the change of adjustment, put the engine in gear, and turn the prop. It will lock-up if it is correct. Be certain that neutral is really neutral and there is no clicking. Reverse usually does not get as much power applied, so you can bias it a little toward forward to ensure positive lock-up. But, don't go too far this will put excess pressure on the brass saddle inside the lower unit and prematurely wear it.

The prop has about 30 degrees free play. IF it drags a lot while you turn the prop through this 30 degrees while in gear, then you are too far biased. There should ne none to very light drag for this 30 degree free play. As I said before, a little adjustment goes a long way. Do 1/2 turn at a time until it positively locks in gear.

 

[kauboy]

Re: '72 45HP Chrysler - no forward gear!

Thanks a ton Frank!!!

I made the adjustment today and tested before reading your latest response.
Did this by setting it in gear, and turning the flywheel.
Before adjusting, turning the fly while in reverse caused counter-clockwise prop turn.
In neutral, no prop turn.
No turn in forward either.

Started making minor adjustments.
Had to make about 5 full turns before getting proper forward gear engagement.
Retested all gears again, and all produced correct prop spin, or lack of.

Tomorrow I'll do the prop turn, and feel for any drag.