Counter Rotating Gearcase Lower Unit on a 140 Crossflow Rare / Useful?

[iloveketchup]

through trial and error, and a lot of going in circles in reverse providing quite a lot of entertainment for passer by's i've determined the gearcase on my apparently 1978 140 crossflow is counter rotating. Meaning if i put a common Right hand prop, if i try to shift into forward, it goes reverse.

This is a problem as although i can just kinda use the controls as is, with a 13x19 right hand prop, the motor will only get up to about 3800 RPM as the actual stroke in the control arm doesn't go as far in "normal" reverse (forward in this setup). Essentially if i were to gun it in reverse the boat could potentially go faster than a normal setup as "normal" forward has more travel.

The solution is to get a 13x19 left hand prop for this gearcase however they are expensive as i've only found them to fit in stainless for around 250 - 300 with hub kits.

I confirmed a few years through shop.evinrude.com (parts catalogs) OMC/Johnson/Evinrude did make a reverse gearcase.

Question:

What was the reasoning for making the counter rotating gearcase? Are they at all rare or more valuable than the standard?

 

[wilde1j]

Re: Counter Rotating Gearcase Lower Unit on a 140 Crossflow Rare / Useful?

Not worth more and not that rare. You apparently changed LU's at some recent point in time. Are you sure you got one from the same model year. Some motors have shift mechanisms which will result in reverse operation with a standard gearcase, if the external gearshift stuff isn't changed also.

 

[jbjennings]

Re: Counter Rotating Gearcase Lower Unit on a 140 Crossflow Rare / Useful?

through trial and error, and a lot of going in circles in reverse providing quite a lot of entertainment for passer by's i've determined the gearcase on my apparently 1978 140 crossflow is counter rotating. Meaning if i put a common Right hand prop, if i try to shift into forward, it goes reverse.

This is a problem as although i can just kinda use the controls as is, with a 13x19 right hand prop, the motor will only get up to about 3800 RPM as the actual stroke in the control arm doesn't go as far in "normal" reverse (forward in this setup). Essentially if i were to gun it in reverse the boat could potentially go faster than a normal setup as "normal" forward has more travel.

The solution is to get a 13x19 left hand prop for this gearcase however they are expensive as i've only found them to fit in stainless for around 250 - 300 with hub kits.

I confirmed a few years through shop.evinrude.com (parts catalogs) OMC/Johnson/Evinrude did make a reverse gearcase.

Question:

What was the reasoning for making the counter rotating gearcase? Are they at all rare or more valuable than the standard?

The only thing I can think of for the counter-rotating gearcase is for use in twin motor setups on offshore boats. The counter-rotation of each motor cancels each other out and makes for a smooth steering setup with not as much steering torque. I think...........

 

[emdsapmgr]

Re: Counter Rotating Gearcase Lower Unit on a 140 Crossflow Rare / Useful?

Your 78 uses the more common gearcase shift linkage found on most later crossflows. The 1977 and older crossflows use the old style belcrank shift mechanism. I believe all the mechanical shift (1973 thru 1977) cases that use that belcrank system function backward. If your gearcase was from an older model, you would have some shift rod matchup problems, however-so that is unlikely. LIkely it is just a counter-rotating case.

 

[wilde1j]

Re: Counter Rotating Gearcase Lower Unit on a 140 Crossflow Rare / Useful?

You're quite right, and zero torque. Very common on all twin engine boats, like mine.

The OP never explained how he got the CR motor or gearcase.