Motor weight

[wisconsinjimmy]

Hello,
I purchased a pontoon with 20' tubes and 30" diameter, the deck is 14' x 8' the total weight now with the 25 Merc is 1200# but I really want to get a new four stroke about 40 hp and I am sort of leaning towards a Yamaha jet for river fishing. What determines the hp of the motor I can put on this and I do not ski or water sport. I am mainly concerned with fighting the current. I enclosed a picture of the transom which is adjustable with a lever. If I calculated it right the log is 98 cuft with a weight of 6106#
Thanks.

 

[wisconsinjimmy]

Let me rephrase this, how much of a motor can I put on this pontoon, my cross C-channel bars are steel and the transom mount is currently bolted to the last two cross members with 3" x 1/8" thick angle. This transom is adjustable with a large lever on the starboard side so I can lift the motor. Most pontoons I see have what looks like a angled down chute larger at the rear then the front.

 

[ahicks]

The 40 4 strokes are a good 50 lbs heavier than a 2 stroke. A lot of that is that they come with power trim, but in any case, you are smart to be concerned about your motor mount. If it were in really good shape and I had the need, I might try it myself, but I'm really shy about suggesting it's fine for others.

That said, I saw an older 100hp Johnson mounted on one of these mounts earlier this summer, and it seemed to be doing OK. Of course it may be on the bottom of the lake today because I just saw it the one time!

 

[wisconsinjimmy]

With the 25HP I am not to worried but this thing hangs quite away's to the rear and only uses 3/8 bolts and there are quite a few pivot points. May be I should get new angle and go one more stringer (?) to give me 3 and weld up a solid transom to keep the motor closer to the boat and far enough away for the power tilt. I have done some searching and will go propeller driven and 40 HP which should be good enough.

 

[ahicks]

You don't see them often, but if you aren't in too big a hurry, you may be able to find a permanent mount type non adjustable transom for sale. Something like that shouldn't be hard to rig, and there would be little concern over a 40-50hp 4 stroke hanging on it. Your 30" tubes would handle the weight fine.

I put a 50 hp Honda on a 16' toon this summer, and it handled it fine (though I'll admit I was concerned going into it!). Granted, this toon was fairly stripped down with just a console and plastic lawn furniture on it, and used only on a couple hundred acre (small) lake. Made for a pretty nice install for the owner, as his biggest priorities were that it would start when he wanted it to, and it would idle for hours without issue. He loves it!