Have I adjusted too much?

[chandlerman]

First, the background. On my 1972 C&C 35, I recently cast off from the dock after dropping friends, coolers, etc. and getting ready to head back out to my mooring. The engine has been running fine all season with no issues.

I put the engine into forward gear and...nothing happened. The prop did not engage. Not sure what to make of it, I pulled it back to neutral, then tried it again. Still nothing. I tried reverse, and it went into reverse, but when I tried forward again, nothing and then when I put it back into reverse, hoping to back myself back to the dock, it would no longer go into reverse, either.

I sailed back to my mooring, then after some browsing here, decided to have a go at adjusting the collar as described in several posts here on the forums.

The first time I tried it, I think I tightened it (turned clockwise) two notches. There was some excitement when I dropped the washer from the set bolt into the oil sump and had to recover it with the ol' magnet-on-a-stick thing, so I may have lost count. Regardless, it didn't fix the problem, though it did seem to catch a little bit if I leaned on the throttle, so I posited that it must need more tightening.

Today, I headed back out to have another go at adjusting it. I tightened it another two clicks, which didn't seem to be enough, so I tightened it another two, put the cover back on and tried the engine again.

Now, while I have a nice firm-but-not-tight detente, watching the prop shaft it looks like it engages before the detente locks and then disengages again by the time it hits the detente.

Have I over-adjusted? Do I just need to back the adjusting gear off a notch or two?

Or are things more severely broken than I realize and it's time to bring in the pro's? In that case, can anyone recommend a good Atomic 4 mechanic who can work on a moored boat Chicago?

Thanks in advance

[SEMIJim]

Hi chandlerman,

Having to adjust a previously-working reversing gear's forcing cone more than one notch, much-less six seems to me unlikely. As Don says in his reversing gear video, regarding that adjustment: A little is a lot.

In his video, Don lists three things that will result in catastrophic failure of the A-4's reversing gear: Brake band adjustment bolt loses its roller.
Brake band pin works its way out
Operating (aka: "forcing") cone bearing "flies apart"(1) and (2) will result in loss of reverse. (These can actually be repaired in-place, btw.) (3) results in loss of forward. Fixing this requires disassembly of the reversing gear, which, given the limited access in most sailboat engine spaces, generally means pulling the engine.

Other than that, I have no insights.

Good luck,
Jim

[jhwelch]

From what you've writting I'd also suspect something wrong with your
shifter cable; perhaps it is slipping against the clamp that holds it.

Disconnect it at the engine end and see if you can "pop" the shift
lever into forwards manually, or lash the shift lever at the engine
end and see if the control in the cockpit slides back and forth.

Good luck!

-jonathan

[chandlerman]

This isn't too encouraging.

I don't have the reversing gear video (yet), but I tested the gear directly with the shifting cable disconnected from the engine and also confirmed that there was no slippage on the cable.

Given the sudden failure, going from working just fine to nothing in a matter of seconds, I've feared that something catastrophic (i.e. would require pulling the engine) must have happened.

Looking at the gear, everything looks OK, but obviously the facts would tend to disagree with my diagnosis. I guess I'll try backing it off some this morning, and then it sounds like time to possibly write my favorite boatyard a large check :( .

Not to mention the fun of sailing up a river which includes two drawbridges to get it there...