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Johnson 25 HP tiller conversion questions

Mike from Atlanta

Regular Contributor
I recently bought a 1977 Johnson 25 hp outboard (model 25E77S) that is set up for remote throttle/shift/steering control and electric start. I actually responded to the seller's ad for a different motor (1973 Johnson 9.5 hp) but couldn't pass up a great deal on the 25 hp. I bought both outboards for $150 apiece. I've already finished getting the 9.5 up and running. Seems like a good little motor and it didn't appear to have many original hours on it. My question is...what to do with the 25 HP?


My situation:


I bought my first boat a little over a year ago (1987 Monarch 1448 aluminum flat bottom jon boat rated for 25 HP). Around the same time I bought a 1973 Johnson 20 HP rope start tiller in pretty bad shape (broken/repaired skeg, rattle can paint job, compression 99/102). With the help of this forum and contributors like Timguy, Joereeves, valvebounce fdrgator and others I gave it a major overhaul over the course of about 3 months and it has run well for me since then. Pushes my boat around 21 mph with 2 guys and fishing gear.


The 1977 25 HP:

I originally bought this outboard thinking I would rob the electric start components off of it and use them on the 20 HP, or take the tiller handle off of my 20 HP and use it on the 25HP. It was only after I got home and started doing research that I found out they went from the 22 cubic inch to 33 cubic inch in 1977 so the parts wouldn't be interchangeable. I started assessing the 25HP and realized it is in fairly good condition and probably a better motor to keep than my current 20 HP. Compression is 122/120. Turned over freely with great spark. No signs of water intrusion in the gear box when I drained the oil, no major cosmetic damage. It was a bit hard to start, but ran, idled, shifted and pumped water well without even cleaning the carb. I monitored the engine temp with an infrared gun and it ran around 145-150F. I'm sure that with a carb rebuild, new impeller and general maintenance this outboard would serve me well for many years, plus give me a bit of extra power and electric start. The only issue is that it didn't come with a throttle/shift control box, steering mechanism or any of the cables for them. It does have the wiring for remote key start with choke and the battery cables.

I don't want to set my boat up with a steering wheel/console because I'm already limited for space with 2 guys fishing onboard. So I'm trying to figure out the best plan to make use of this outboard. Apologies for the long-winded post but here goes with the questions...


Option 1- find a donor tiller handle motor to convert mine to tiller


-Does anyone know what is the range of model years the 1977 Johnson 25HP is compatible with? Is it the same model year range with the Evinrudes? Does it matter if the donor motor is electric start vs rope start? I'd love to find a tiller handle donor motor and convert the one I have. I attempted to figure it out myself but comparing part numbers was a bit mind boggling. I would think that I could use the steering bracket/handle off of any of the 20/25/30/35 motors.

 
Option 2- find a used throttle control box and make a custom tiller handle for steering

-I met a guy at my local lake who had done this in order to use a remote control motor as a tiller. He fabricated a tiller handle out of some steel tubing and a bit of angle steel that bolted up to the U shaped handle on the front of the motor. He mounted the key start and throttle control box next to the driver's seat position for throttle control . He shifted gears manually using the lever on the side of the motor, steered with his homemade tiller. He did a fairly good job with the fabrication/ installation and it didn't look terrible. Maybe in the future I could add stick steering which wouldn't take up so much space (don't' want to spend the money for that right now).


My question is which control box should I buy if I go for this option? I looked at used control boxes on Ebay and tried researching it a bit, but couldn't figure out which boxes would/wouldn't work? What would be the most cost effective way to do this?


Option 3- sell the Johnson 25 HP and try to find a tiller handle, electric start 25 hp


-I bought this outboard because I knew that even if it didn't work out for me, I could resell it for more than the $150 I paid for it. If it turns out that it can't be converted to tiller steering without major expense/headache, I'll just sell it and try to find a good deal on a tiller handle 25 HP with electric start.

 
Does anyone have any thoughts on what I should do with this outboard? Or any better ideas that I haven't thought of?
 
Fdrgator and Boobie- Is there a particular reason why you think I should just sell it? Is the 1977 motor less desirable than other older Johnson motors? Is there something else I should be looking for instead?
 
Mike, my response was based on what you said yourself. Comparing parts becomes mind boggleing. As it is, you have a remote motor that you can sell to help pay for a tiller motor. But if you buy another motor for parts, you will wind up with what you want.....AND a pile of parts from a scavenged motor, which you bought and probably will never use. Why put yourself through all the work and expense?
 
Racerone- it does not have the correct steering bracket for the tiller handle. I realize that to convert to tiller steering would require that bracket and quite a few other parts to be changed. I thought the best way to do that would be to find a tiller steer parts motor that is compatible, but I'm not sure what model year/hp range is compatible. Based on looking over the parts diagram for various years and how's I think it's 1977 to 1982 20hp to 35hp, but I'm not sure about that.

Also not sure how to determine which control box would be compatible.
 
Fdrgator- That sounds entirely reasonable and thanks for the advice. I think the only reason I'm even thinking about converting this motor to meet my needs is that it's tough to find one in this condition, for such a good price in my area. I may end up selling it, but I'd like to put at least some effort into researching other options.

One reason I'm considering the homemade tiller handle is that it wouldn't require me to find a parts motor or store all the extra parts. It also would require me to permanently alter the motor so that it could be used as intended down the road. I'd just need to get a control box and cables. I'm just having difficulty figuring out what kind of control box I'd need. One lever or two? Original Johnson/Evinrude from eBay or could I use one of the newer universal ones?
 
Also, I think that I can sell it more easily and for a much higher price if it comes with a throttle control box and cables. It may be worth it for me to spend a bit more up front in order to sell it for more.
 
A lot of this depends on your budget.------Your ambition.--------Availability of used / parts motors in your area.-----Supply and demand.-------Time frame that you want to get this project done in.------If you want it done in a week , you might have to spend more money !!
 
A number of remote controls will physically work, though may not be "correct". Most differences are related to the switches and wiring cables. With that in mind, the simplest ones would be the good old standby twin lever Johnson Shipmaster or Evinrude Simplex control (same). NO wiring or switches at all in those.
 
Racerone- I like tinkering, so I don't mind putting some work into this project. And parts motors do pop up on Craigslist and Facebook Marketplace pretty regularly. Im always scanning for a good deal on something. I just need to know what model years and horsepower s would have the right parts. And I don't need to be in a rush with this motor. My 20hp pushes the boat just fine and now I have the 9.5 for limited horsepower lakes. I currently own 3 Johnson outboards that are older than I am (I'm a 1979 model year).

Fdrgator- thank you sir. Simple is exactly what I'm looking for. I'll start keeping my eye out for a good deal on a Johnson Shipmaster or Evinrude Simplex.
 
Just for fun you can give Tim's Outboard in Hackensack MN a call. They would likely have what you need for the conversion. Just call 218 682 2331, Mike or Dan. I might have everything here at my shop too, but I would not likely know for sure until most of the snow melts and I can get back to look in my semi trailer.
 
Timguy- I'll definitely call Tim's Outboard. When I was working on my 20hp last year I ordered a bunch of parts from them on your recommendation. And then again when my original hood flew off on the highway. Everything I got from them was in good shape and reasonably priced. I'll see if they have what I need to convert my remote steer to a tiller, and if not maybe they'll have a control box I can use asking with a homemade tiller handle.
 
If you go that route, they may have the front shift adapter too which is really handy. With my feelings on the 33 cu in, that is a sweet motor with great compression. This group of motors make up a large portion of our Ontario camps transportation. Everything is tiller because we need to lock stuff up off season. Running the older motors discourages thief's activities because it's not worth their effort to haul them out by snowmobile some 30 miles. You would be surprised how much theft, break-ins, and vandalism takes place back in the "bush". Got to be humble, however, 'cause the next time I show up, my camp might be a pile of ashes. Really try to keep stuff around that isn't worth stealing.
 
Timguy- my feeling about outdoor equipment in general is that I don't want to own anything that's going to break my heart to lose it. I was at Bass Pro Shop the other day and took a stroll part the new Mercury outboards. Sweet machines indeed, but a 25hp would be worth more than my boat, trailer, outboard and the truck I pull it with put together.

I've been up to your neck of the woods and it's beautiful. 6 years ago a friend and I rode motorcycles from Atlanta up through Minnesota, up to Sioux Lookout and past that to Ear Falls. Beautiful, wild country up there.

I'll call Tim's tomorrow.
 
We camped in tents at a moose camp on a tiny lake outside of Ear Falls the last night before we headed back south. It was 15 degrees Fahrenheit and sleeting in mid September. When we left Atlanta 7 days earlier it was 92 degrees.
 
Right, you guys are so correct. Mosquitoes, Black Flies, can eat you alive too. A little battle every now and then with nature is not all bad. That 33 cu in. Can keep you a step ahead with those flying beasts. When you come around the corner, watch for the eagles and white pelicans. They are giant up here. A few miles an hour can get you up closer sometimes. The avatar was taken on Clay L. Wabigoon River, part of our portaging to camp Big Canon. This photo along the Wabigoon near Segise Lake about 2 miles from the portage. White pelicans and Seagulls.IMG_20190830_183156311_compress13.jpg
 
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Timguy- I just got off the phone with Dan at Tim's Outboard. He's got all the parts I need to convert my motor to tiller steer for $75! Plus he spent a few minutes on the phone talking me through the swap process and making sure I had all the necessary parts to do the swap. Better and cheaper than any of the options I was thinking of. Thanks again for sending to Tim's!
 
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