alpha drive wont go in reverse

[MattM]

Got the Z21 home from arizona. Took it out, works great, nice handling boat.

But, the alpha drive won't go into reverse abut 2/3 of the time. When I move the shifter I here a light grinding kinda sound. Is this a cable adjustment. How do I fix it?

Also the boat is missing the gas cap. It's a pretty big cap, bigger on the Zs than I've seen anywhere else. Anybody know where to get one?

thanks, Matt

[MOP]

I would start by checking the drive cable if it is Ok then go by the directions in the Merc Manual.

[Donzigo]

The gas cap and cap recepticle were made by Perko in Miami. They have long ago discontinued that design. But, I lost one years ago myself and a call to Perko did the trick. They said that although it would take a while, they would make one for me and they did exactly that. Nice folks down there.
You might also check some of the surplus places like The Marine Connection, Ft. Pierce, Florida. They have 2 giant warehouses full of stuff. 727-465-6560. FYI - They aren't the cheapest guys in town; but, then again, you're looking for something special and hard to find, right?

[pmreed]

Check your ignition cut-out switch. If it's not functioning, you can grind your poor old dogs. Purpose of the switch is to momentarily unload the drive gear so it can mate up with the driven gear. The other problem with this switch is for it to stay engaged too long and the engine dies. Just as you're trying to dock too. Yes, it's happened to me. Sounds like yours isn't working at all. Check the adjustment or replace if broken.

Phil

[Rootsy]

ahhh the grinding of the dog clutches... yes as MOP alluded to the cable from the drive to the interrupter can and will stretch over a period of time. i have also seen the control to interrupter cable stretch though less common... Which will throw the whole thing out of whack and you'll grind the dog clutches and not go in gear or kill the motor or worse of all not be able to get it OUT of gear (kinda hairy around docks). The mercruiser service manual #6 has a complete procedure for adjustment of the shifting system. If you cannot get the adjustment correct with the procedure the next step is to replace the cable from the shift interrupter assy to the sterndrive. which is a rather UNFUN job in some cases...

In principle the shift interrupter works on a principle of tension. you shift and the tension in the cable from drive to interrupter causes the cam to overshoot and trip the interrupter switch momentarily killing ignition because you cannot get the clutch to disengage when it is loaded in gear... also you cannot get it to go into gear with the motor running (kinda like shifting a manual trans from a dead stop without a clutch). In the alpha all of the gears are spinning when the motor is running.. the dog clutch is affixed via a cross pin to the propshaft.. when it engages the gear the propshaft then spins. if the cable throw is adjusted either side of neutral any appreciable amount then you won't force the dog clutch in far enough in one direction or another and it'll grind and not engage...

If for some reason you have a bind in your shifting system within the bellhousing or drive you will encounter problems also...

i could attempt to put the procedure into words as best as my memory serves me but it'd be a LOT easier to just get a service manual so you have it in front of you.. right from the mercruiser mouth... it;s a 2 or 3 page procedure... with some diagrams... besides i think everyone who owns a boat should have the proper service manuals if you plan to do ANY work yourself...

lastly... the worst thing to possibly do to the dog clutches is to ease them into gear or grind them in... you want a swift firm "CLUNK" into gear... both forward and reverse... if you grind them in your just take the edge off of the dog clutch teeth and the gear dog teeth...

JR - man of SS shifting issues...