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I have an 86 Viper and I was hoping someone would be able to give me some direction for boat setup.

A little background:
Right now the boat has a 115 Merc in-line 6 on it with low water pickup and a 6 inch jack plate. I am running a 12 or 13 inch high five prop with 26 pitch...this is what the previous owner used for years. The old Merc has been giving me problems so I decided to buy a new 115 Merc Pro Xs with a 20" shaft.

Questions:
1. What prop should I be using with the new motor? I called Mercury and they said that a 4 blade 24 pitch prop might work well for good take off and top speed...What do you think?

2. The motor is not on the boat yet so I am still thinking about where to mount it on the jack plate. The old Merc was a 25" shaft and this new motor has a 20" shaft, so the placement is going to change. Where should the new motor be mounted? I have attached a picture of the rear of a viper...where should the fin of the motor be located in comparison to the back of the boat for optimal performance? Should the fin be in line with the pad or the notch above the drain hole? I might be getting a nose cone on this motor in the future so I would like to factor that in as well. Thanks for the help!

Welcome to the forum.

I'm assuming the new xs is a 3 cyl like the regular 115 opti.

I would agree a 4 blade 24 would be a good all around prop.

I guess I would mount the motor down one hole from the top on the jack plate. Then use a water pressure gauge and go up till you loose pressure or start to slip.

It should be a good fun setup with the new 115.

Welcome and I would really like to see more pictures. The colors look great on what I can see.

Also, I would do as chet says. I think he is our resident viper guru. LOL

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Thanks hippie but I'll be the first to admit I'm far from a expert.

Actually I have herd I'm a little on the nutty side a lot today during testing.

Thanks for the welcome and the responses. Yes, the 115 XS is a 3 cylinder. I am still a litle nervouse about going from a 6 to a 3 but the dealer said they make it work with the computer stuff they have done to the new motors. I just hope it has the same kind of power that the 6 had...although I guess 115hp is 115hp.

The picture I posted is not my boat...I just used the picture because you could see the back of the boat clearly. Below are pictures of my boat.





And an action shot

Very nice! I love the blue and silver flake. Then again blue is one of my favorite colors.

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Cool, that's what mine looked like when I started.