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Discussion in 'RD's Lounge' started by 2FORCEFULL, Oct 14, 2010.
does the "R" on my drive....1.50R,,, stand for righthand??
it has rh prop
1.5 ratio, right hand rotation
Where are you seeing this "R?"
I don't think it would matter to the drive if it was right hand or left hand rotation as you could just run it in reverse? (Switch the cables up at the controls)
Only if you want to blow up your drive. Many bravos have helical (?sp) cut gears and are only designed to run one direction.
Well there ya go.. So I guess it's only XR's you can run both directions?
that was my next question... when i had twins, people would say, swap the props and run them in reverse....
first time I noticed the "R"... it stamped 1.50 R
I know someone who had both drives rebuilt and was told by the builder to break them in running them in reverse (flip flopped) or he wouldn't warranty them.
Awkward to drive but i've never heard this before.
They run either way. I just called to ask my Merc rep if they even sell a reverse rotation Bravo 1 and they do not.
Here's my thought on the foward reverse deal. I noticed on twin motor boats turning in the port side drive is usually the one that fails. That's spinning in the normal rotation, the starboard is spinning in "reverse". The port side drive is using the upper gear, with the cap holding it in for support, the starboard is using the bottom gear with the base of the driveshaft housing supporting it. Maybe it's just coincidence, but they seem stronger using the bottom gear.
You can swap them and wear the other gear in the gear set. I recommend it.
I have heard this from other people as well - Seems like the drive that is turning left is the one to break more often..
Go to MaxMachineWorks in Havasu tomorrow and they will give you all the answers....Plus you could pick up the Bimini top for delivery Vic will be up there in the morning. Call me
2forcefull , pop the upper cap . If you got straight cut gears ,you can change the rotation any time. I have the B1 X diesel drives with straight cut gears , steel reinforcement in the tower with thicker floor for the gear .Changed props rotation at 100 hrs inwards for better handling . Now I have 200 hrs on the pair with no ill effect.One other thing ; the X models have net forged gears ,the Bravo1 doesn't .The steel tower can be installed in the B1 case, but not sure if you can get a tower from Merc.
You guys do understand there are two gears? One on top and one on the bottom. They work both directions straight cut or not. The motor spins the same direction, the input shaft spins the same direction. Both gears always move in the same direction. The clutch either engages the bottom or top gear to change the direction of the upper driveshaft. Mercury does not make a reverse rotation Bravo. You can switch the direction with the shifter.
does the "R" on my drive....1.50R,,, stand for righthand??
Outdrive , my only concern to 2Forcefull's drive was if he had helical gears in his bravo1 drive behind a healthy engine .Helical gears have higher sideways thrust loads (axial loads) and slightly lower efficiency than straight spur gears, hence my suggestion to replace the cap.
The bottom gear is helical also, it still turns the correct way.
Is there more upper failures than bottom gear failures , unless one hits a log or sandbar , of course ? I think Merc reinforced the upper bearing cap for X models because of the side load . Seen unworn upper gears with missing teeth on them .
What Outdrive 1 and RD said, It's Ratio not rotation, there is no such thing as a left hand or right hand bravo, to get opposite rotation you engage the cable the other direction which engages the opposite gear.
TRS, III, IV, V, and VI on the other hand have a left and a right hand version
Why dont you just switch the drives left to right and then switch the cables at the front? Then the drives are still turning the same direction and you dont have to worry about the gears taking on a different pattern. (I'm assuming you want to have the drives spin in the opposite direction they are now) Are they turing out or in?
Mike @ Prime Marine
Mike , 2Forcefull has a single now . His drive may have XR gears already , also seems the gimbal is an HP unit as well ?
Dumb Question, what about single engine Fountains ?
Didn't BK Reggie set up everything lefty ?
Special drives ?
Duuude, re read the thread, it doesn't matter, you just set the cable to push rather than pull for forward to switch rotation. it's basically running it in 'reverse' although it's not really reverse because there is no difference in gear load on a bravo between forward and reverse, it just drives the top gear rather than the bottom.... No such thing as a special drive. :bash:
Now with a TRS or something else with a real transmission, velvet drive for example, running in reverse will kill the tranny, because you are putting all of the load through the actual 'reverse' gears in the trans, and they are not designed to handle that kind of load or power.
Here is a visual display to make it easier to understand
Hmmmm i'm not sure what you mean by this. And i'm not sure if your confused by OD1 said about upper and lower gears, or if you are actually asking a completely separate question.
This is what is meant by Upper and Lower Gear, as you can see they spin opposite directions naturally, by engaging the clutch that locks that gear to the down shaft you control direction of the downshaft, No shifting takes place in the lower unit.
This same theory is how TRS, III, IV, V (i'm not sure about VI) drives reverse rotation, they do it in the lower unit, if the drive is set up with the prop shaft gear IN FRONT of the down shaft it spins one way, if it's set up with the prop shaft gear BEHIND the down shaft gear it spins the other way.... there are only 2 gears in the lower unit, not three, so it looks similar to this (but no clutches and one gear isn't there, depending on which gear isn't there is LH or RH rotation)
So are you still asking about lower unit gears breaking? because that's a completely different issue than shifting and LH vs RH.... :thumbsup
Am I to understand it turns the same way? .....don't confuse facts with internet bench mechanics....
Nicely done Racey. That should clear it up.
I am rebuilding my broken Alpha Drive that died last trip and all that shifting happens in the lower unit. The upper gear-case is clearance set and that's it. 100% opposite of the Bravo Drive. I never knew that until now. :thumbsup
My upper is what broke but I have not a clue how to get the metal particles out of the lower w/o tearing it apart. To do that I need special tools. Is there any way to flush things? The metal shavings are small but I don't want to replace the upper everything and then have debris destroy it later on.
Anyway, great cut a way view.
Now that Racey posted a picture , you'll understand what I meant about top cap loading. With 99% of engines turning clockwise , the green arrow on the bevel gear indicates that the bottom gear is the forward gear [ LH prop rotation] being used 99% of the time for forward movement.Shifting the cables at the helm for right hand prop rotation indicates that the top e gear [yellow arrow] would be the forward gear .If that gear is a helical gear , it would take the sideload ,hence the steel reinforcement of the bearing cap for X drives.
All Bravo drives old and new have only two gears in the bottom ,because of the cone clutch doing the shifting in the upper housing.
I thought everybody knew that ,lol.