Basic Merc tower project questions

I currently have a 2004 Weeres Sportsman 200 20’ pontoon with a 40hp Mercury on it, and I grew up with an invader fiberglass boat and 1986 Mercury 90hp motor. (See profile pic)


I miss the sound and smell, and raw feeling of power. Armed with some general engine and electronics knowledge and a lifetime of boating, I aim to rebuild a 90-115 tower of power (ideally as close to an 86 as possible) and eventually pair it with a Hydrostream.

in the meantime once I source a tower motor, I plan on putting it on my pontoon for testing and fun.

Here are some preliminary questions I have before I kick off a search for the right motor:

1) do I need controls with motor, or is it likely my controls will work with an old tower? I’d assume maybe some adaptors, brackets or slight mods.

2) do I need the original power trim with the project motor? Or can I reuse/separate my current system that works with my 2004 40hp? I know this is a dumb question, but I’m swallowing my pride.

3) other than cylinder compression, are there any essential red flags that are specific to this era of towers? On the flip side, which parts are common and easily replaceable?

4) are their any other issues I need to consider about connecting this project motor to my pontoon? The label says it can handle up to a 115, so I assume I don’t need to modify the pontoon transom for weight/power reasons.

I appreciate your guys time. I scanned through this forum, for quick guides on this sort of topic and didn't find any. If you know of any links or stickies or anything, PLEASE, let me know, I hate to ask you guys to reinvent the wheel for me.


This is a long time coming, and if you’re willing to help with a little back and forth in the beginning here, I can source a motor and start the first part of the fun. I have some pics of things, and I will be at my cabin every weekend in order to take more, or gather specs/diagrams info about pontoon config as needed.


I look forward to the project, and to letting my 9 and 12yo sons hear and feel the old Mercury tower of power once again.

Jim

Welcome to the site. The old inline 6 can be a great motor or a pain in the a**. I think most parts can be sourced but many have been discontinued. If you are mechanical i have a couple 115s that need fixed I will sell real cheap. Good luck with your project.

Rock

Could not post pics in pm so here they are. Didn't say they were pretty but I would guess there are enough useable parts to build one and have some spares. No clue on the years.

Rock

Looks like 79 in back and 82 in front. Could be some mismatched coverings