backassward gearcases

[Detroit Whitey]

Ok i have heard tihs going around for a while has anybody took a stock gear case put it in reverse and used a left handed prop and if so are what the failure issues?

[Mark Poole]

Failure issues..... answer... 100%

The forward gear and pinion are a matched set. That is why when you buy one it comes as both. Next time you have a gearcase apart look at the forward gear bearings and support compared to the rear. Although all three gears spin together the reverse is not designed to be high speed load bearing.

[Tomtall]

Also - Most reverse gears do not have a thrust bearing designed to take the constant thrust of power, If you look at a counter rotation gearfoot the rear gear has a bearing designed to take the constant thrust.

[Ron Hill]

I hear the tail cone, tail stock, like to back out while running in reverse.......BUt, in Canada in the 8 HP Bathtub class they were all running left hand wheels. I thought I heard they ruled this out...but because of expense, not failure rates...

As I recall, I asked Fred Hauenstein, when he worked a Mercury Racing and he said..........not quoting, but he said....probably NOT a good idea!

[Bill Gohr]

We saw alot of these at OMC that came off twin rigs that had the wrong props on them, it really has nothing to do with gears and lash, but the loading of the gears and the prop shaft. On a RH the prop shaft is locked to the fwd gear by the Clutch dog, and spins with it, if you go "bassackwards" as you say, the propshaft is now spinning opposite the forward gear and the LH prop is forcing the shaft into the fwd gear and in a very short time the propshaft will eat itself into and through the forward gear, not much left of them at that point. makes junk fast.

[Powerabout]

Not to mention the rev gear bearing that is not really designed for much load and then blowing the bearing carrier out of the gearbox on overrun due to the gear load...

LH powerhead is the answer

[Popa Sam]

Just curious..How is the left powerhead the solution if you have a right gearcase?

[Bill Gohr]

Just curious..How is the left powerhead the solution if you have a right gearcase?


But these are spiral gears designed to push apart under load so if you spun them the other way they would pull together and self destruct even quicker, as far as the reverse bearing goes, yes that is true but the propshaft eating the forward gear happens much qucker.

[mercguy]

But these are spiral gears designed to push apart under load so if you spun them the other way they would pull together and self destruct even quicker, as far as the reverse bearing goes, yes that is true but the propshaft eating the forward gear happens much qucker.


I completely agree! Seen it happen twice before. One Yamaha customer accidently (parts dept fault) bought a left hand prop and decided instead of ruining his weekend of boating, put the motor in reverse to try......lasted about 5mins............

[Powerabout]

I guess i'm thinking Mercs with straight cut gears
OMC did make CCW V6 and V8's though with the appropriate parts to retain forward in the front of the gear case.

[Bill Gohr]

Yes we did make Counter V6's and 8's, that ran backwards in 85-87' however it was impractical, the linkage was hokey to run the timing backwards.

[Fast Fred]

worked on one of them a$$backward runnin motors once, i was like WTF?!, but got some help, got it fixed and rigged, good stuff hear.:cool: