15-20hp outboards

[bonz_d]

I have a 14' glass tri-hull with a 56" beam, unsure on weight or caps as the tag is missing. Simular to the old Tuffy and Lunds

Looking for a proper sized outboard for it. I have a 1969 9.5hp Johnson but I believe it will be under powered for this boat. What I've been looking at are mid 70s 15hp OMC and Mercs, mid 60s, early 70s 18-20hp or 25hp. Though I think a 25hp will be over kill.

Confused on which will have the best power to weight ratio and whether I should be looking more OMC or MERC. Though I've been reading here and have noticed that the Mercs of that era are prone to driveshaft and ignition problems. Reliability and maintenance are important as I would like to be able to service this myself.

The 9.5 I have is a nice running motor but then I've sense read a thread here that they are really nothing more than a hopped up 7.5hp. So far I'm leaning towards a 18-20hp OMC.

Opinions please!
Kevin

 

[tashasdaddy]

Re: 15-20hp outboards

that may be to small. formula for hp can be found here.
http://forums.iboats.com/showthread.php?t=191283

 

[bonz_d]

Re: 15-20hp outboards

Thanks,
Went to the link, read it, remeasured the boat @ 13.5 x 50" at transom. Then calculated it to 20hp by their formula. Guess I wasn't far off by my guess and experience. Just off by the actual measurement.

Now it looks like 15 to 20hp works. Is there a site that I can find the actual weight of different makes and models. Are the 18 Evinrude and 20 Johnson basically the same engine? Any idea how much of a performance drop there would be if I dropped down to a 15hp?

Thanks again.

 

[tashasdaddy]

Re: 15-20hp outboards

18 & 20 are basically the same, a 15 in good shape, compression wise, may be stronged than a 18 or 20 with less compression. i think with a trihull, i would look at a 25, as the tri hull glass boat is going to be harder to plane.

 

[tmcalavy]

Re: 15-20hp outboards

If it were mine, I'd shoot for a late 50's to late 60's OMC...18 to 33hp. 18 may be too small, but a 25, 33 or even 35 hp would do the job nicely especially if you carry any gear and buddies.

 

[bonz_d]

Re: 15-20hp outboards

Here's a pic. , I think you will see it's not as big as you think.

Thanks

 

[jbjennings]

Re: 15-20hp outboards

Looks like a 25 would be about right to me if the transom is perfect. How is the transom, but the way? If it's rotten a 20 or 25 will gradually rip it apart.
Nice looking rig. A 35 would be awesome but I don't think the transom will hold up to it as the corners look kind of weak--I'm no expert on fiberglass, though.
JBJ

 

[bonz_d]

Re: 15-20hp outboards

Transom is solid but not very beefy. No way I'd put more than a 25hp on it. Even that I think would be a bit much or the upper limit. It's only 50" wide at the transom and 56" midship.

Another view. Overall the hull is in good shape. Deck needs to be replaced and the boxes on the sides should be opened to check foam as the glass has cracked and delaminated in spots. Initial investment, $100.00 with trailer.

 

[jbjennings]

Re: 15-20hp outboards

Nobody knows better than the person actually looking at it what it can handle. I think a 25 would be ideal for it but like you, an 18 would probably be all the stress it can take. I despise fiberglass work but that will be a neat rig when you get done with it. Oh how glad I am that it's you replacing that deck and not me!!!!
I kind of like that nice clean (flat) floor. I've never seen but maybe one or two boats like that, so of course, my advice is pretty worthless. I wonder if you can beef up those transom corners while you're glassing the rest of the stuff?

Edit: I reread your first post and I think you're right on everthing you were thinking. Go with the OMC, 15 or 18hp. (I'm very biased but I like mercs too and just ran my favorite today--a '72 9.8hp) I wish I knew how much it weighed. Your 9.5 will be underpowered just like you thought. It will load it up and decrease the rpm's which would probably wear out your motor faster. It might not even plane it. I wonder if you could talk a friend into letting you test out their 15 or 18 and see if it would plane it and if so, how easily?
Enjoyed the pics,
JBJ

 

[bonz_d]

Re: 15-20hp outboards

One of the reasons I bought it was because of the open floor. The wood decking under the glass is only 25" wide x 3/8" ply and does not cover the whole deck. If you look at the aft area where I already started to cut out you should be able to judge the width of the plywood.

This boat is a Hy-Ryder, was manf. here in Tomahawk Wisconsin and was built in 1979. Don't know the model name. Company went bust a couple years later.

Agreed this should work very well for the types of lakes we fish here in S. Wisconsin. But what's really great is the wife loves to fish also!

I've thought about 25's but not sure if the boat is wide enough to support it well enough w/o drawing to much water.

 

[tashasdaddy]

Re: 15-20hp outboards

the way the tramson is braced (see picture), if the wood is good in the transon, it will handle a 25 with no problems. the difference in weight between the motors we are discussing, is minimal. this is also a perfect candidate for stick steering, and remote control.

 

[pecheux]

Re: 15-20hp outboards

I like the walking area in your boat. I own a 14 footer V hull (245 pounds) and am pushing it with either a 9.9 or a 15 hp (I have both) It will plane when alone in it with the 9.9 and will plane with the 15 hp with two onboard. A 20 hp would be ideal on my boat ... Based on the performance of my boat, 15 could be at the low end on you boat being heavier. Just sharing infos ...

 

[bonz_d]

Re: 15-20hp outboards

Thanks everyone for the input so far. Haven't had an oppertunity to actually try it in the water with my 9.5hp but that may give an indication of how underpowered it would be. May just have to take a test spin before I start the resto.

Though again by what I came up with from the link provided a 18-20hp is max. if used as a tiller steer.

 

[mickjetblue]

Re: 15-20hp outboards

A test run with your 9 is a good idea.
A big factor is going to be the weight of the boat, and that will probably
be more when your resto is completed than what the boat is now.
Your 9 will do the job for fishing, but if you want the max speed, then
20 - 25 would be much better. Wish you the best with it, and like to
know how things go. Neat boat design for fishing.

 

[pecheux]

Re: 15-20hp outboards

Follow up ...

I prefer using my 9.9 for fishing so when I do I make sure most of the weight in front of the boat ... especialy the gas tank ... and I ajust the motor angle adjustement so it is close to the transom so it has a tendency to lift the rear of the boat. Depending on how far your fishing spots are ... lol you may turn out satisfied with the OB you already own

Cheers.

 

[F_R]

Re: 15-20hp outboards

Bonz, in your original post you said the 9.5 is a hopped up 7.5. Horse Hockey. There is no resemblance between the two. Might have the same spark plugs. No, even that is different. Ah, same magneto, that must be it.

 

[bonz_d]

Re: 15-20hp outboards

Read it in this article, under history. But seem to remember hearing the same thing before that.

http://www.sschapterpsa.com/ramblings/Johnson 9.9_15.htm

 

[jay_merrill]

Re: 15-20hp outboards

The motor on the boat in his second photo is most definately a 9.5 hp and, no, these motors were not "hopped up" 7.5 hp motors. In fact, they were completely unique to the rest of the OMC product line. As FR pointed out, about the only similarity to the other OMC motors might have been coils, spark plug wires .... and, perhaps, the fact that they were water cooled, two stroke outboard motors.

I just surfed the net a bit to see what I could find out about these boats. There isn't much out there but the few examples that I did find seem to have motors on them in the 20 hp to 30 hp range.

My best advice to you on this boat is to get someone who knows fiberglass repair to give the boat a "looksee." It might be ok but, for the 100 bucks you have in it, it might be worth re-doing the transom, floor and stringers. By the look of the boat, none of this would be particularly difficult.


PS: Do horses play hockey well? Have they ever won the Stanley Cup?

 

[tmcalavy]

Re: 15-20hp outboards

Depending on how you refit the deck, that rig would be real sweet with an 18 to 22 hp Johnson, long tiller and center seat; or stick steering. The stick and throttle arrangement Tashasdaddy has posted in some of his forum pix is a good example.

 

[bonz_d]

Re: 15-20hp outboards

I just surfed the net a bit to see what I could find out about these boats. There isn't much out there but the few examples that I did find seem to have motors on them in the 20 hp to 30 hp range.

Wow, if you found any you did better than I did. The Shell Lake, Lund and Tuffy from what I've found are all a foot longer and 10" wider than this boat even though they look very simular. Which is why I believe they are getting 25 and 35hp outboards on them. My next door neighbor has a Tuffy with a 25 Johnson on it and it is considerably larger than my boat.

The way this boat is built there are no wood stringers in it. The rises that are on each side of the keel were designed to support the deck. Then there is 1 Stringer down the center of the keel. Which I'm not certain ofwhat it's made from yet but that is not wood either. It's hollow! And yes this is still the original deck in this boat. Again, the wood part of this deck is only 25" wide.

I'll have to start a thread in the Restore Topic and post a bunch of pictures. So keep a watch! Originally I was just going to quickly do the deck, add some seats, mount the 9.5 Johnny on it and go fish. But I'm finding that this little boat is kind of unique so I decided to take the time and do it right.