Repowering with 110HP

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Don & Robbin
deckhand
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Posts: 24
Joined: Tue Jul 01, 2014 4:53 pm

Repowering with 110HP

Post by Don & Robbin »

We are repowering and replacing the transmissions. We have an '04 with 75 HP and 2:1 trans. I think I have found all of the previous posts but it's a big project and I don't want to miss anything. Any info is greatly appreciated.

If you replaced the trans, what was the ratio and which prop? 17 x 17 seems to be the preferred size.

Did you reduce the port pitch by 1/2" to compensate for the reversing gear?

What was the length of the wiring harnesses to the flybridge and to the motors? I'm replacing the control panels with 4 B20's and rebuilding both helm stations.

Did you remove the doors and frames to the cabins? Any issues getting the motors through the opening?

Thanks,
Don Sayre
Ripple
pdq039@gmail.com
makala
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Joined: Tue Jan 17, 2017 11:18 am

Re: Repowering with 110HP

Post by makala »

See here from a post on this site from "Catrina"- Some pictures that might help showing an installation..


https://tinyurl.com/y8ne8zdr
Don & Robbin
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Re: Repowering with 110HP

Post by Don & Robbin »

The photos are a great help.
Thanks
Cat Daddy
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Joined: Tue Sep 03, 2013 10:26 pm
Location: MV34 #32

Re: Repowering with 110HP

Post by Cat Daddy »

Sorry I am a little late to the party. I did this a year ago with mechanical 110's. Can't help with the harness length, I reused the originals.
My research found all MV34's regardless of horsepower used the same transmission and same ratio. The 3200 rpm engine requires a bigger " bite" so I used a 17x19 based on two other boats with 110's. The prop shop recommended 17x18 and I will repitch when I get a chance, I'm about 150 rpms low.
I went through the deck for access. Gregg Burdick told me the added expense of a gantry system would probably be as costly as the fiberglass work and there is a good chance of damage to inside furniture and woodwork. My deck repair was about 4k. Also i didn't have to disassemble new engines.
For the lower helm remodel I overlayed with 3/16" lexan and vinyl wrapped that with a carbon fiber print. Really happy with it.

Good luck,
Rafe
Rafe Williams
"Cat Daddy"
MV34 #32
Cat Daddy
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Joined: Tue Sep 03, 2013 10:26 pm
Location: MV34 #32

Re: Repowering with 110HP

Post by Cat Daddy »

PXL_20211202_152236640.jpg
Rafe Williams
"Cat Daddy"
MV34 #32
duetto
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Re: Repowering with 110HP

Post by duetto »

nice job rafe!
john & diane cummings
duetto mv34 #23
Don & Robbin
deckhand
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Posts: 24
Joined: Tue Jul 01, 2014 4:53 pm

Re: Repowering with 110HP

Post by Don & Robbin »

Rafe,
I'm leaning towards cutting the deck for the same reasons you mentioned. Replacing the harnesses will probably be the biggest headache. Your helm looks great. I'm using cherry for the inside helm, teak on the flybridge, replacing all of the switches, and upgrading the electronics.
Thanks for the info.
Don Sayre
Ripple #39
Don & Robbin
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Joined: Tue Jul 01, 2014 4:53 pm

Re: Repowering with 110HP

Post by Don & Robbin »

The new motors are installed so we have 2 - 75's for sale if anyone is in need. The motors run perfectly. We also have 2 sets of 4 blade props.
Don & Robbin
pdq039@gmail.com
Attachments
Yanmars 2.jpg
Yanmars 1.jpg
Don & Robbin
deckhand
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Posts: 24
Joined: Tue Jul 01, 2014 4:53 pm

Re: Repowering with 110HP

Post by Don & Robbin »

In hindsight, cutting the decks was the best alternative. The deck opening was very useful for passing tools and parts. The transmissions were easily removed and installed with a rope. It also provided great light and ventilation. A water dam was installed around the opening. The lids from the packing crates (wrapped in heavy plastic ) made good covers. A few pavers on top prevented them from blowing away.

I used a multi-tool and jig saw to cut the decks at a 30 deg bevel. The jig saw blades were made for carbon fiber and cut the decks like butter. Reinstalling the cutouts was another decision, leave it to professionals, or do it myself. Other owners paid in the $4K range. I got a quote for $6K, so I'm doing it myself for around $500. The photos show the corner supports to accurately level the panels. I used structural polyester putty to fill the saw kerf. Underneath, I installed 2 layers of 1708 biaxial cloth/mat, 6" then 8", with 4 layers at the corners. I will do the decks in the fall to avoid dripping sweat in the gelcoat. I plan to dish out the deck joint and fill with several layers of cloth tape. Prior to reinstalling the cutouts, I took one to Fiberglass Coatings in St Petersburg. They custom matched the gelcoat color. The finished product will probably not match the pros, but $5500 in the bank will ease the pain.
Attachments
deck reinstalled.pdf
(644.57 KiB) Downloaded 134 times
deck leveler from top.pdf
(644.73 KiB) Downloaded 123 times
deck leveler from bottom.pdf
(644.73 KiB) Downloaded 115 times
deck cutout with water dam.pdf
(613.24 KiB) Downloaded 130 times
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