After replaceing everything , engines,cables,a lower unit, my engines quite often die when shifted into gear. I have adjusted the system as merc. has recomended and rechecked it several times The drives are 1987 alpha ones origional to my '87 Donzi Z29. I realize they will not likely live too long behind the pair of 558 hp blower motors but I am hoping they will last until I find a better replacement that I can afford. Maybe next year. The old engines were around 330 hp running 3 blade 22 chopers I went to 28 pitch bravo with the new engines. Could the major prop increase be part of the problem? The shift Kill micro switches are lingering a bit more than I would like in the kill zone but much less and the drives won't shift. so I increased the spring tension by bushing the posts on the shift plate with some short pieces of fuel line. It helped a bit. Aside from scraping the drives and fitting some new serface drives does anyone have any suggestions?

The shift interrrupt should not be hitting at all when going into gear, they should hit coming out of gear only. That is usually caused by a bad lower shift cable or mis-adjustment. There is a newer style shift bracket that has a plunger switch and a spring loaded thingy that really improves alpha shifting, but the cable still needs to be perfectly free.

Your problem might just be that the engine can't carry the load when you put it in gear. That is pretty common and can be hard to fix without raising the idle too much.

If its not the shift cable or adjustment, what is the timing set at on your motors? More initial timing may clean up the idle and allow to shift into gear without stalling. I don't think it matters all that much because big block blower motors will DESTROY those drives.

Wow Marc,

Such a good response, but gotta love the word "thingy"

558 hp can eat a full coarse bravo meal easily enough, and alpha is basically just a snack......;.. just set the rev limiter for 1500 rpm and have fun.

The amazeing thing is these poor Alpha Ones have lasted 26 ,over 6000 hours and 4 engine swaps of varying horse power levels, drunken abuse by past owners with engines far beyond what Alphas were made for. The past service records show that they were well maintained and that the only repairs were due to hitting rocks. And now a wee 250hp increase, they may well break but at $600 ea. upper or lower unit how many would I have to break before I reach the cost of a pair of drives that would be proper, about 100 or so I would guess.

I had problems with my Alpha's also dying when shifting out of gear. Heck, some died shifting into gear mine were so far out of adjustment. I found it was really a three person job to try setting them. One to hold tension on the prop once in gear, one to move the shifter and me to watch the linkage for when the switch pivoted under load and made contact. doing that we could fine tune them until they just barely engaged the micro switch. Definitely touchy!

I keep thinking about getting rid of mine, but with only 300 HP sbc a side, I really do not compare to what others are running through them.

Good luck.