Is 3hp going to be enough?

[cmuman]

1) I have a 15'6" 1976 saf t mate tri hull with a 70hp evinrude on it. I wanted to get a kicker motor to have for trolling/emergencies. I obtained a 1964 Johnson 9.5. It's too wide. There is another local guy that has a 3hp Johnson that I've been looking at. Is that motor going to be enough for my boat? How fast should this motor get the boat going in case I need it for a back up situation?

2) The model number on the side is
j3retb
I used to be able to find a link on here to decode it, but my wife cleaned the computer history, and it wiped out my link. now I cant find it. Anyone know a good place to decode this?

 

[cmuman]

Re: Is 3hp going to be enough?

I found the engine decoding link. If I do this right, I think it is a 3hp Johnson rope start built in 1993.

 

[jameskb2]

Re: Is 3hp going to be enough?

Depends on conditions. I have the same engine, 1962 version, mounted on a 12' aluminum shallow V hull. It will push us around the lake no problem, (my wife and I) even on a mildly windy day with some light chop.

However, the wind does play with it.

I got a call at 11:00 PM one night, from a friend of mine that needed a tow. I said sure, where are you? He said....on the lake. He owns an 11 passenger Viking "party barge" and it was maxed with beer drinking people.

Dead battery.

So, I reluctantly went out there. It was a flat calm, not a breath of wind. Tried to jump it with a jump pack I brought, no dice.

So, what to do? Tow it.... We hooked to the bow ring, I pulled the cord and fired it up. That little 3 horse towed the boat of 11, plus my wife and I in the 12' pram, all the way to the dock. It worked hard, but it did it. I think if there had been a wind though, it might not have.

That's all I can say. It will certainly work, but in a storm? High wind? Can't say.

What you could do is ask the seller if you could test it on your boat. See how it runs, and how it works for what you want. There won't be any water speed records set, I can tell you that!

 

[tashasdaddy]

Re: Is 3hp going to be enough?

you would do better with a bow mount trolling motor. i have a 3 hp also. it will move you, be extremely noisy, and struggle, as it would not be propped correctly, a cross wind will play havoc.

 

[jay_merrill]

Re: Is 3hp going to be enough?

It will most likely push your boat about 4 mph in a no wind to light headwind situation. Any wave action will tend to slow it down from there.

As I have mentioned in a couple of other threads, I had sort of a strange setup that involved a pair of Johnson 6hp motors on a 15 foot fiberglass tri-hull. Both motors would push the boat at about 8 - 9 mph and one would push it at about 5+ mph. I have one of those motors on my current tri-hull, which is 17.5 feet long and, according to my GPS, it will push the boat at about 4.75 mph in a calm situation.

I recently tried a Johnson 4hp that on my current boat but ended up going back to the 6hp. My choice had to do with two things - shaft length and boat speed, The 4hp shaft length is barely long enough to get the cavitation plate level with the bottom of the boat, even though it is a v-hull and the motor is mounted well off to the side, and it just doesn't push the boat very well. A less important factor is that the 6hp has FNR and the 4hp is "pull and go" (no gears).

If you can fit a 6hp beside your main engine, and can find one for a good price, I think you will like the setup. If not, I would go for either an older OMC 4hp or a 5hp, with the 5hp being the preferred motor. I really like those motors because they mate a detuned 6hp powerhead with the midsection and LU from the 4hp. They are small. light and powerfull for their size.

 

[tashasdaddy]

Re: Is 3hp going to be enough?

can you use an auxillary mount? it doesn't have to mount directly next to the main motor.

 

[cmuman]

Re: Is 3hp going to be enough?

I could put a mount on the transom. The only problem I run into is that the mount woudl block one of my hooks on the back of the boat if I want to pull a skier or a tube. I usually run my boat on a 200 to 300 acre lake that is rather protected, so I think the 3hp will be alright. I might just have to pick it up and have both in the arsenal.

 

[jay_merrill]

Re: Is 3hp going to be enough?

If you are in a relatively small and protected lake, I woud agree that the 3hp is fine. In this case, really all you need is something to get you to the dock and even if you are on the opposite shore, it won't take long. Just be aware of the shaft length issue and be sure that the LU is submerged enough to insure adequate water flow to the impeller. The good news is that, just by sitting at the stern in a 15 foot boat, your body weight will probably be enough to make the boat "squat" enough to get the kicker deeper into the water.

 

[samo_ott]

Re: Is 3hp going to be enough?

The downside, as stated, in my opinion would be no FNR. You cant idle it, it's pull and go. But the lake sounds small so it should work fine. Heck you could paddle home!

 

[cmuman]

Re: Is 3hp going to be enough?

Why couldn't I idle it? It does have forward and neutral.

Luckily my transon tapers to a little less that 15 inches high where I mount the kicker. The short shaft fits perfect. The cavitation plate sits right below the bottom of the boat.

 

[davemaxi1970]

Re: Is 3hp going to be enough?

I have a 4hp 1981 Johnson that we have had since new, never let me down and has pulled my boat (15ft and very heavy) several times when the big motor has given up for a distance of 4 miles in 4ft swell. That 3hp wont get you home in a hurry but it will get you there. Dave

 

[cmuman]

Re: Is 3hp going to be enough?

Just as long as I don't have to row for 4 miles I don't care what speed I'm going.

 

[cmuman]

Re: Is 3hp going to be enough?

Is a three horspower twin a dumbed down 4 or 5 horse or a stretched 1 or 2 horse?

 

[cmuman]

Re: Is 3hp going to be enough?

I got the motor and it is just spotless. This thing runs like its brand new. It is way lighter than my 9.5 evinrude. I think its going to work just fine. I'm hoping to try it out this weekend.