Switching from a RH to a LH prop

xsnoboard · Aug 15, 2011

I have a Volvo Penta AQ125B with a Volvo penta 270. I believe there is a RH prop on there right now which is shot. My boat came with a brand new LH prop. I was wondering if I could use the LH prop without changing the gearing.(use reverse to go forward etc...) If not, how hard is it to change the gearing and what does it entail.

Thanks!

Texasmark · Aug 15, 2011

Re: Switching from a RH to a LH prop

Check the dimenisons...dia/pitch to answer your question. The only reason for LH was for dual installations where you could balance out the prop torque.

Only problem may be some balance problems that will surface with the prop torque in the opposite direction, like the boat may want to list to the Port (left) side. If so, shifting weight around the boat could offset it.

Also, the trim tab may need to be put to the same degree of offset, but to the opposite side. Propeller torque in now coming in the opposite direction which could cause the steering to become an issue.

My 2c,

Mark

am_dew · Aug 15, 2011

Re: Switching from a RH to a LH prop

In addition to what Mark said, you can easily change the rotation on a 270 drive. Here are the instructions for doing so:

http://www.panix.com/~am_dew/270_change_rotation.jpg

Texasmark · Aug 15, 2011

Re: Switching from a RH to a LH prop

am_dew said:
In addition to what Mark said, you can easily change the rotation on a 270 drive. Here are the instructions for doing so:

http://www.panix.com/~am_dew/270_change_rotation.jpg

Very tactful sir. Yes I did forget that on LH and RH installations, the prop shafts are turning in opposite directions so to make this work one has to do that.

My compliments,

Mark

xsnoboard · Aug 16, 2011

Re: Switching from a RH to a LH prop

So Basically I just need to change the shift rod from position A to position B and I'm all set.

Thanks

am_dew · Aug 16, 2011

Re: Switching from a RH to a LH prop

xsnoboard said:
So Basically I just need to change the shift rod from position A to position B and I'm all set.

Thanks

Yep, that's it. I'd also replace the cotter pins used to hold the shift rod. As Mark said, you may find that your boat will list to one side after you do this...that happened on my boat and adjusting the trim tab did not help, so I switched it back after buying a different prop.

xsnoboard · Aug 18, 2011

Re: Switching from a RH to a LH prop

Just to verify.... Should I ignore this part? Or should I be doing something with the shift control? I moved over the shift rod as it said.

NOTE: The rotation must not be altered by inverting
the control levers.
For both a left-hand and right-hand threaded propeller,
the control cable has a ?push? motion for engaging the
forward gear. Check and adjust the shift control according
to Part VII, points 8?14.

wellcraft19 · Aug 18, 2011

Re: Switching from a RH to a LH prop

No, by moving the "linkage" at the outdrive, you are NOT ignoring this.
It essentially only tells you that you MUST push the control lever FORWARD when you want to move forward.

Safety aspect since, if you did not move you linkage at the outdrive, you could just continue driving "forward" by moving the "control lever" towards the stern. If you at the same time happen to lose you your balance, you and other boaters might be in a very dicey situation with an accelerating vessel, possibly with a driver that is now overboard.

am_dew · Aug 18, 2011

Re: Switching from a RH to a LH prop

EDIT: I agree with what Wellcraft19 said.

SparkieBoat · Aug 18, 2011

Re: Switching from a RH to a LH prop

I guess I/O outdrives are different than outboard motors. with an outboard motor a LH foot is different because of the constant forward thrust. I found this out the hard way, I was taking a OMC outboard CR gear case apart and could not get the bearing carrier out, I torched, beat, banged, bent/broke 2 pullers, then I grabbed the prop shaft and it just pulled right out, shaft, carrier and forward gear all in one piece. so I guess on an I/O this is not the same.

xsnoboard · Aug 18, 2011

Re: Switching from a RH to a LH prop

Well this was a waste of time for me anyways. The new prop that came with the boat is a 15 Diameter and 19 Pitch and it hits the exhaust outlet. The prop on the boat is a 14 diameter 19 pitch... The 15 seems alot bigger than 1 inch... It just BARELY doesnt fit.

I wonder If I can go with a 14.5.

Anyone know what would be best? I would like something good for towing skiers/wakeboarders...

SparkieBoat · Aug 18, 2011

Re: Switching from a RH to a LH prop

need to know what your WOT speed and RPMs are..and what is the recommended RPM range for your motor???

am_dew · Aug 18, 2011

Re: Switching from a RH to a LH prop

SparkieBoat said:
need to know what your WOT speed and RPMs are..and what is the recommended RPM range for your motor???

I'll help out with the last part of Sparkie's question. According to the V/P manual for the AQ125B:

Max RPM: 5100
Max Cruising RPM: 300-500 below the above max (or 4600-4800 RPM)

xsnoboard · Aug 19, 2011

Re: Switching from a RH to a LH prop

Well when I use iboats.com to select a prop for my outdrive it shows a 15 diameter 19 pitch. I am pretty sure I have it on the correct way but it hits the exhaust. Seems like its only 1/8 of an inch too big

am_dew · Aug 19, 2011

Re: Switching from a RH to a LH prop

xsnoboard said:
Well when I use iboats.com to select a prop for my outdrive it shows a 15 diameter 19 pitch. I am pretty sure I have it on the correct way but it hits the exhaust. Seems like its only 1/8 of an inch too big

As long as the prop hub is mated with the prop shaft splines, there really is no other way it can go. Well, you can put it on the shaft upside down but that would not cause it to not clear. If it's an 1/8 too large, I don't see that you have any choice but to find a smaller prop. As for the pitch, without knowing what the WOT RPMs of your boat are with a known pitch prop, it's not possible to say for sure if a 19 pitch prop is best or not. What kind of boat, length, and approx. weight?

xsnoboard · Aug 19, 2011

Re: Switching from a RH to a LH prop

Actually if I put it on backwards it clears.

I have a 1985 Sunbird 17ft and I think the boat weights 1600

am_dew · Aug 19, 2011

Re: Switching from a RH to a LH prop

Do you have any idea what WOT RPMs the boat went with the old 19 pitch prop?

My boat is about the same size as yours but with a 4 cyl AQ130C and a 19 pitch is perfect for cruising but my hole shot is not that great. If I were to pull skiers or tubers, I would switch to my 17 pitch and keep an eye on my RPMs to be sure I did not go over the max for my engine.

SparkieBoat · Aug 19, 2011

Re: Switching from a RH to a LH prop

a set of trim tabs can really help pulling skiers, or just if you want faster hole shots and lower planing speeds. without changing to a lower pitch prop.

5t1cky · Aug 27, 2011

Re: Switching from a RH to a LH prop

Would this also be the same on a 280 drive?

wellcraft19 · Aug 28, 2011

Re: Switching from a RH to a LH prop

@5t1cky:
If you are asking about "modifying" the out-drive to support a propeller with different rotation; Yes

Switching from a RH to a LH prop

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