New Member working on old boat!!!

[broncotwisterjim]

Hello,

I just joined up and am hoping you guys can give me some much needed advice. I've read many posts here and see there is a wealth of knowledge! I have a jon boat that my grandfather bought new at Sears in 1973! When I was a kid, we used it on some larger lakes with an outboard, but for the past 15 years or so, it's been on our pond here at the farm and I use it with just a paddle.

I've decided I want to use it again on some larger water and inshore for reds, flounder & trout at the coast. I was too young to remember what type/size outboard we had before, so my first question is what horsepower you guys would go with and for weight and any other good reasons, 2 or 4 stroke.

The second question is related to replacing the transom board. I have read info here about this job and that was very helpful. There is a 1/4 circle shaped brace riveted through the floor and then attached to the bottom center of the transom board. To get the new board in, it looks like I would need to remove this and then put it back in. Is this the best way and are stainless screws & nuts with silicone okay to go back with? I have no leaks and don't want to cause any. There is an aluminum cap over the transom board that is welded on each rear corner, so to go in from the top, I would need to take that out and have rewelded.

Here are the specs on the boat:

1973 Sears Jon Model # 61816
Serial # APBP1235M73J
15hp max
505lb max wt of persons
705 max wt of persons, motor & gear

Thanks in advance for any help!

 

[DaveInGA]

Answers in red in the quote below.

Hello,
Hello, welcome to the forum.

I was too young to remember what type/size outboard we had before, so my first question is what horsepower you guys would go with and for weight and any other good reasons, 2 or 4 stroke.
Based on the specifications you listed below, the maximum horsepower you could use is a 15 horsepower motor. If you have a trailer and don't have to carry the motor or take it off the boat, it won't matter if it's a two or four cycle. Two cycles are lighter, but are noisy and you have to mix the oil with the fuel. Four cycles are heavier, but they are also quieter, get better gas mileage and you don't have to mix the fuel. If money is a consideration, an older two stroke can be found cheaper than a newer four stroke.

The second question is related to replacing the transom board. I have read info here about this job and that was very helpful. There is a 1/4 circle shaped brace riveted through the floor and then attached to the bottom center of the transom board. To get the new board in, it looks like I would need to remove this and then put it back in.
If you remove the hardware holding the support to the old transom board, you may be able to get the old transom out and the new transom in without removing the brace. This is the approach I would take. It would be helpful to see a picture.

Is this the best way and are stainless screws & nuts with silicone okay to go back with?
If you don't have to remove it from the boat, I wouldn't. I would recommend re-riveting with sold rivets if possible or closed end rivets if not. But it would be better not to remove it from the bottom of the boat if possible.


I have no leaks and don't want to cause any. There is an aluminum cap over the transom board that is welded on each rear corner, so to go in from the top, I would need to take that out and have rewelded.
If you are going to have to have the cap re-welded, you could remove the center brace, then have it welded back into place. I suggest you post pictures so it can be determined if you really need to remove it or just remove the bolts holding it to the transom.

Here are the specs on the boat:

1973 Sears Jon Model # 61816
Serial # APBP1235M73J
15hp maxThis is your maximum horsepower rating. Only an experienced boater should exceed this and I would not. It is based on the size of your boat, it's strength and the strength of the transom.
505lb max wt of persons
705 max wt of persons, motor & gear

Thanks in advance for any help!

Hope this helps.

 

[broncotwisterjim]

Thanks for the reply, Dave! I attached a few pics of the transom area, before & after removing the old board. There were 2 pcs of 3/4 plywood. One extended down to attach to the bracket and the other was shorter and just covered the top half. there is only a 3/4" space behind the bracket.

I have read some places that people had a board on the outside of the aluminum transom also. Is this something I should add? This boa only had the wood on the inside.

On motors, I was only considering a 9.9 or 15 and thinking I might should go with a 2 stroke to keep weight down. Not sure the 9.9 is enough. Opinions?

Thanks again!

Jim

 

[Vermonster]

Hi Jim,
Any chance you can post a picture of the back and sides of the transom caps? In order to get a nice fitting transom in there you're going to want to remove them, and seeing all sides of them will let us know what you have to work with.

As for adding another piece of wood on the outside, adding one wouldn't hurt because it will give something for the motor to "bite" into rather than your aluminum hull. You wouldn't need another 3/4" piece however and it wouldn't need to be the entire width of the stern either - just enough for the clamping on the motor. 1/2 inch ply would be fine, but if you only want to buy 1 sheet of 3/4" use what you have and save cash. I would bolt it through the entire transom with stainless steel hardware sealed with 3M 5200. As for plywood, exterior grade is fine - look for Auroco at Lowes. As for treating it after it's cut, there are 2 options that are recommended:

1. Coat it with epoxy (water) and paint (UV) it (will last a lifetime).
2. Coat it with 3+ coats of spar urethane (will last a long time).

As for your motor... I would look for a 2 stroke 15HP.

 

[DaveInGA]

Jim,

Vermonster is giving excellent advice and I can only second all of what he has said.

 

[broncotwisterjim]

Thanks guys, for all the info so far! Dave, I agree on Vermonster's info. I looked at the refurb he did on his boat and it's pretty awesome! Thanks, Vermonster! As requested, here are a few more pics of the transom area. Hope this shows what you need to see. I'm 45, but I'm really excited about breathing life back into this old boat. I can remember being on it with my dad & grandpa when I was about 10! My dad & grandpa even took it to Canada for 2 weeks when I was in middle school. I'm still mad today that they didn't let me go!

I have found what I believe to be a good deal on an immaculate 1990 Evinrude 9.9 2 stroke here in my area. A local mechanic told me the only difference in the Evinrude 9.9 & 15 is carb and that the 9.9 can be adjusted to run like a 15????? I don't know, but it's the best motor I've found so far. Think it's enough?

I've got the boat in the shop now, trying to smooth out some dents and dings, ready to fix transom and prep to paint. Thanks for all your help guys!

Jim

 

[Vermonster]

Yep those transom caps definitely look welded! That's beyond my scope entirely as I just don't have the tools to deal with it.

I'm thinking that somebody on here would be able to point you in the right direction. A masonry wheel on a grinder might cut through the weld (I think I read that maybe from a BigWave post earlier), but hold off until somebody can confirm how to pull those off. It would be best if you can salvage and re-use them so the cleanest way to remove them would be best!

As for the motor I've read that the carb is the only difference between a 9.9 and a 15. I think some guys on here have actually swapped it out and left the 9.9 cowl on for those 10HP max lakes too! :twisted:

You can likely get by with just the 9.9 for now and test it out. As long as you aren't in rough seas I think the 9.9 would be fine.

 

[broncotwisterjim]

Thanks for the info. Yep, they are welded on the corners and the aluminum skin of the transom wraps over the top of the transom board, so it would have to be bent up and then put back, hopefully without messing that up. I really had no idea that replacing this board would be so involved. Hoping for more good info, like you provided.

This 9.9 is so pristine and hard to find, I think I'm going to give it a try. If things get too rough, I don't figure I'll want to be out there in that little flat bottom anyway!

In the one pic from the rear, you can see that the top rail on the port side has an area that is bent downward, from about midship forward a few feet. I am trying to straighten that. Did you have to do anything like that on yours? Any tips on straightening?

Thanks again!

 

[Vermonster]

I wouldn't bother straightening it out. You might do more damage and weaken the hull more by trying to fix it. It's just character in an old boat

 

[broncotwisterjim]

Thanks Vermonster! Anyone else that could help me with this transom replacement, I'd sure appreciate it. Main question is should I remove the brace that has 4 rivets through the floor OR remove the welded corner caps and bend center part to get new board in that way. As shown in the pics, the corner caps are welded in three places. Any help appreciated! I have it in my shop here at home and ready to get on with the work!

Jim

 

[MaineFisherman]

I can't speak to the transom replacement, but I can say that 9.9hp is plenty for your boat. I have a 12' sears semi v, and a 7.5hp motor, and it's fine. And I'm running in a tidal river and John's Bay on the coast of Maine. I think you'll love that 9.9!

 

[novaman]

It looks like the easier way to get the new boards in would be to grind the 4 rivets on the transom brace in the floor, than to cut all of that weld loose. You'll ruin by far more material cutting those curves on the corner caps , and spend 4x the time on doing it. I'd use an angle grinder with a thin cutoff wheel on the rivets, cutting them off on the top of the transom brace and when it's time to reinstall use 4 SS panhead 1/4" machine screws from the outside coming in. Seal with 3M 4200 or 5200 , under the entire foot of the transom brace, and the same screws thru the transom, with the same sealer, etc. Just my $.02 worth.

 

[broncotwisterjim]

Thanks for the info, you guys! I picked up the 9.9 today. Looks great and now I am in HIGH GEAR to get this transom done, so I can go run the boat with the motor and see how it goes! I stuck a couple boards in tonight just to use to mount the motor real quick and see how it looks. Pics below. The cavitation plate is sitting 2" below the bottom of the boat. I have read some differing opinions about where folks think this should be. Can you guys give me some input on that. Ok, or do I need to modify?

Novaman- I agree on your method being the simplest and that's the way I would go on my own. I just wanted to make sure I'm not going to start a dry boat leaking! I've done that type of deal on fiberglass boats above the waterline, but never on aluminum and definitely not on the underside of the hull!

The motor came with the hose and a metal tank that looks NEW. I can hear a little liquid sloshing around in the can and I know it hasn't been used, but stored inside, for quite awhile. Should I wash it out with something before putting gas in or just dump out the old and go?

Thanks again!

Jim

 

[broncotwisterjim]

Ok, so I replaced my transom board, painted my boat on the outside and had a Rhino liner sprayed on the inside. Looks good and is running out great with the 9.9 Evinrude. Found a deal on a 30lb troller, hoping that will be enough to push her along. I found an old trailer that was in BAD shape and refurbed it in my shop. Turned out good. Now, I want to look at building a front platform for mounting troller, fishfinder & seat. Can you guys give me some advice on how high is ok and do I need to be concerned about the platform being too much weight added to the boat? Any pics of builds would be great! Also want to look at adding a livewell or just aerating a cooler.

Thanks!

A few recent pics without clamp-on seats, outboard & troller:

 

[jasper60103]

That would make grandpa proud.
The boat and trailer look great. Good job! =D>

 

[broncotwisterjim]

Thank you, sir! I hope so. I spent many days fishing with him in it.

 

[broncotwisterjim]

Does anybody have any front deck info you could share or pics would be even better? Just curious how far you can go on a 1436 without being too heavy or having weight/balance/center of gravity issues. I want to put my troller up front, mount a chair and fishfinder. Thanks

 

[Ringo Steele]

Hi Jim,
Nice job on the boat and trailer! I wish my Cox trailer looked that good! It's good to revive a rig with sentimental value, isn't it! My Ouachita and trailer were my uncle's. I got if from my aunt when he passed. It had been sitting upside down in their back yard for close to 20 years. My transom came out in chips and dust! I pulled the transom knee on mine, and used 1/4" SS panhead bolts and nylock nuts. Dry as a bone! Use sealer or nylon washers under the bolt heads, and no worries about leaks.

 

[broncotwisterjim]

Thanks, Ringo! Yeah, I feel very fortunate to have the boat and the memories that go along with it. All the work has been a pleasure. The old Cox was quite a mess when I started! Your transom rebuilt looks top-notch! I used spar urethane and stainless hardware. I too removed my center brace and re-installed it. All seemed to work fine and I have no leaks.

Now moving on to the decking and trying to figure out what's ok and what's not. I have tried to read through older threads here and it looks like most people feel that a 36" wide floor is the breaking point for to deck or not to deck. My main objective is to mount my transom troller, with the head reversed, on the bow, create some hidden storage and have a good spot to sit, run the troller and mount a fishfinder. Hoping to get some pointers and pics of projects completed.

Thanks!

 

[broncotwisterjim]

So, this is my boat that I want to build a front deck in. Can anyone give me some pointers on the best way to construct this?