V4 foot or V6 foot on a 140

[mhg]

I have a 1989 140 looper with a 20" v4 foot
I have picked up a 1986 140 looper with the 20" v6 foot
The power head has a spun bearing with the v6 foot
Does it make sense to change to the larger foot and swing the larger prop
I currently will have to go up to at least a 21" pitch at this time due to some
upgrades I have done, and I got a 14 X 21 SS prop in the deal
I would tear it down and replace the seals and impeller at a minimum before
changing out
So what do the experts think about doing this
I will either sell the v4 or the v6 foot as is depending on which way I end up going
Thanks Mike

 

[ezeke]

Re: V4 foot or V6 foot on a 140

The big difference is the gear ratio; you will have to reduce the pitch of your propellers to run with the V6 drive (if it really is a V6 drive).

 

[mhg]

Re: V4 foot or V6 foot on a 140

So the next ? is what would it need to be a V6 drive
It has the large dia. case with 15 spline drive and enough clearance for a 15" dia. prop
check the ratio by turning the drive shaft and counting the turns
drive shaft 30 turns and the prop shaft 14 turns
Approx. 2.15 to 1 if I did it correctly
Not certian if I have it in forward or reverse if it would make a diff.
Changing the prop is not a concern as I need to do that any way
After changing the carbs and jets I can now turn my 19 pitch blade at 6700 rpms
Must go up any way
Any one else with an opinion
I just want to get an idea as to whether this swap would be worth the extra work
Mike

 

[Dhadley]

Re: V4 foot or V6 foot on a 140

The V4s did not come with a true V6 unit. Some V4s had a V6 style (size) case but used a lower gear ratio than the typical V4 rather than a higher ratio like a true V6 case. You'll need a larger diameter prop with the 15 splines as you noticed.

Also just make sure the tach is set on position 6.

 

[kenmyfam]

Re: V4 foot or V6 foot on a 140

I have the 13 spline on my 1985 Looper. Changed from the original one.

 

[ezeke]

Re: V4 foot or V6 foot on a 140

The propeller gear ratio of the small 13 spline gearcase is 13:26

The propeller gear ratio of the large V4 looper 15 spline gearcase is 12:27

The propeller gear ratio of the large V6 looper 15 spline gearcase is 14:26

The gear ratio of the small unit is 2.00
The gear ratio of the large V4 unit is 2.25.
You need to raise the pitch on the large drive prop approximately 12% to equal the speed (and thrust) with the small drive.

 

[mhg]

Re: V4 foot or V6 foot on a 140

So I have a large V4 foot that has the 2.25 gear ratio
I actually think this is better for me as I will have a lower gear ratio
this should allow me to spin up quicker with the larger prop for better planing
I think?
Now for the question of is going to the larger, stonger, heavier foot a good idea
As for the cost I will only incur out of pocket for seals and new pump and
a couple hours of my labor
Thanks for all the info. It has been a big help
Mike

 

[mhg]

Re: V4 foot or V6 foot on a 140

So I have a large V4 foot that has the 2.25 gear ratio
I actually think this is better for me as I will have a lower gear ratio
this should allow me to spin up quicker with the larger prop for better planing
I think?
Now for the question of is going to the larger, stonger, heavier foot a good idea
As for the cost I will only incur out of pocket for seals and new pump and
a couple hours of my labor
Thanks for all the info. It has been a big help
Mike

Any other thoughts on doing this swap based on just the merits of the larger and stronger foot and larger diameter prop
Thanks Mike

 

[kenmyfam]

Re: V4 foot or V6 foot on a 140

Should not be an issue, just prop it accordingly.