Classic AquaSport

Aquasport Model Rebuilds, Mods, Updates and Refreshes => Generic Aquasport Rebuilding Topics => Topic started by: kraw2 on February 11, 2012, 03:35:05 PM

Title: Horse Power options for a 1976 170
Post by: kraw2 on February 11, 2012, 03:35:05 PM
Hello,

The 170 that I am restoring came with a 1980 Evinrude 70 hp. What can I expect out of this engine when running?

What HP is recommended? What is a good all around HP to get if I don't like the Evinrude 70..?

The boat is out for paint now and I will post a lot of pictures of the progress. The hull is going to be Fighting Lady Yellow b/c the painter has some left from another job.
Title: Re: Horse Power options for a 1976 170
Post by: Blue Agave on February 11, 2012, 04:18:48 PM
What is the max HP rating for a 1976 170?  Does it still have the factory plate that states max capicity and HP?  I go with a 90hp or 115hp.  I'm not familiar with the 170, but the others should chime in.
Title: Re: Horse Power options for a 1976 170
Post by: Capt. Bob on February 11, 2012, 04:32:38 PM
130 hp
Title: Re: Horse Power options for a 1976 170
Post by: illman on February 12, 2012, 11:11:31 PM
nothing less than a 90
Title: Re: Horse Power options for a 1976 170
Post by: gran398 on February 12, 2012, 11:42:45 PM
Had a friend in the 80's who ran one with a new (then)  90hp 3 cyl. Yamaha.... 42 mph WOT, all you need.
Title: Re: Horse Power options for a 1976 170
Post by: akbridge on February 13, 2012, 08:52:07 AM
I have a 90 evinrude on mine.  I am very pleased with performance.  I have it propped a little slow right now with a great hole shot.  But I can swap my three blade 17" prop and hit 39-40.  A new old stock yamaha would be great.  My dad has an etec 90 on his whaler.  It runs great.  I have been reading a lot on Tohatsu.  They are supposed to be tanks!  They use the same technology injection as a OptiMax.  Either way a 90 should be all you need on these boats.
Title: Re: Horse Power options for a 1976 170
Post by: akbridge on February 13, 2012, 09:01:38 AM
I just reread your post.  If your 70 is propped right you should see decent performance with it.  Those engines are known to run for ever.  Power will be marginal for pulling a skier or tuber if over propped.  It is a lighter engine, a bonus on these boats.  Run it and see how it performs.  If it doesn't do what you want someone will always buy an engine in that size and power range.
Title: Re: Horse Power options for a 1976 170
Post by: gran398 on February 13, 2012, 11:27:33 AM
Quote from: "akbridge"
I just reread your post.  If your 70 is propped right you should see decent performance with it.  Those engines are known to run for ever.  Power will be marginal for pulling a skier or tuber if over propped.  It is a lighter engine, a bonus on these boats.  Run it and see how it performs.  If it doesn't do what you want someone will always buy an engine in that size and power range.


I agree with AK. Those 3 cylinder OMC's are good running engines...same engine Yamaha duplicated with their 90. I'd run it first and see how she does.
Title: Re: Horse Power options for a 1976 170
Post by: flounderpounder225 on February 13, 2012, 12:22:42 PM
Here is a brand new 4 stroke Yami.. sounds like a pretty good deal.  And it's right over in Milton...
http://pensacola.craigslist.org/boa/2832788637.html (http://pensacola.craigslist.org/boa/2832788637.html)
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on February 13, 2012, 08:59:14 PM
I have a 76 170. The max hp is 115. I'm running a 115 yams two stroke.
Title: Re: Horse Power options for a 1976 170
Post by: Capt. Bob on February 14, 2012, 09:19:56 AM
Quote from: "Fletch170"
I have a 76 170. The max hp is 115.

Veeery interesting. :scratch:

Here's specs on a 75.
http://www.classicaquasport.com/gallery ... 552/page/1 (http://www.classicaquasport.com/gallery/showphoto.php/photo/2717/sort/1/cat/552/page/1)

Specs on a 80.
http://www.classicaquasport.com/gallery ... photo/2845 (http://www.classicaquasport.com/gallery/showphoto.php/photo/2845)

Specs on an 84.
http://www.classicaquasport.com/gallery ... 573/page/1 (http://www.classicaquasport.com/gallery/showphoto.php/photo/2855/sort/1/cat/573/page/1)

And the only new boat I ever owned.
http://www.classicaquasport.com/gallery ... /574/page/ (http://www.classicaquasport.com/gallery/showphoto.php/photo/2859/sort/1/size/medium/cat/574/page/)

No, that's not me in the photo but I do have a hat like that. :mrgreen:
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on February 14, 2012, 11:05:36 AM
HAHAHA Bob, I'd say, those are some hotpants!!!!!

Maybe it is 130? I could have sworn it was 115. Regardless, anything over 115 is just ridiculous. Slap a 130 2 stroke on there and the only thing that would be in the water would be the prop....sometimes.

I've taken a lot of weight out of my boat, and with the 115, I've been told she might crack 50....which is nuts in a little 17.
Title: Re: Horse Power options for a 1976 170
Post by: Capt. Bob on February 15, 2012, 08:57:23 AM
My 86 came with a 70 hp 3 cyl. from Bob Hewes. I traded for an 85 model yr. 115 Johnson so I don't know how well the 70 would push it. Still, those 170s are light and I'd bet it would sip gas. Got to admit though, the 115 was fast but a 90 would make it just about right, IMHO.

Fast is fun but fuel costs aren't. :(

Good luck.
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on February 15, 2012, 12:35:41 PM
I'm thinking of running nitrous.

BTW, anyone know what would be a good prop for the 17, running a 115 Two Stroke?

-Fletch
Title: Re: Horse Power options for a 1976 170
Post by: kraw2 on February 17, 2012, 05:48:45 PM
I'm going to stay with the 70 Evinrude for now. The motor has been completely gone thru and painted with Evinrudes new blue flake color. The gas prices are going to be crazy this summer.

My Ocean Master center console holds 320 gallons and I get non ethanol fuel at the marine. It could get up to $6.00 or more a gallon. The refineries charge $1.00 more for NOT adding ethanol.

Thanks for the replies..!!
Title: Re: Horse Power options for a 1976 170
Post by: akbridge on February 17, 2012, 06:27:17 PM
Quote from: "Fletch170"
I'm thinking of running nitrous.

BTW, anyone know what would be a good prop for the 17, running a 115 Two Stroke?

-Fletch
A 17 inch pitch three blade should do well. Are you going to run a backplate or use it for skiing?   If so you might drop down an inch and go to a four blade.  I think merc props fit that engine.  That opens your possibilities up.  Merc props are some of the best.
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on February 17, 2012, 08:45:57 PM
The only thing I'll be pulling behind the boat is a minnow bucket.
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on March 28, 2012, 02:37:51 PM
Since I'm not doing any skiing with this boat, is a 21" pitch,  13 3/4 " prop going to work? I want to get the most out of my top end. Will this bog the motor?

BTW, I have a 97 115 Yamaha 2 Stroke.
Title: Re: Horse Power options for a 1976 170
Post by: akbridge on March 28, 2012, 07:03:32 PM
Thats too big for your engine.  Your hole shot will be slow.  And your top will be poor with you engine always lugging.   I run a 14 inch pitch and have a mean hole shot and mild topend.   A higher pitch does not mean more speed.
Title: Re: Horse Power options for a 1976 170
Post by: kraw2 on March 29, 2012, 11:21:45 AM
I changed my mind again....

After going thru amd repainting the Evinrude 70 hp. my friend wanted it really bad for his work barge.

He was in a bind and needed it right away to keep working.

Because of his lack of patients (sp) with working on outboards he traded me (2) 5Ohp, (2) 90hp, and a 115hp. All the motors are 1990's and above with the 115 being a 1995. The 115 has 150 psi all around. I will sell the others for parts if they are not worth the time to get right.
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on March 31, 2012, 02:32:00 PM
How about a 17 pitch, 13.2 diameter prop? Yamaha shows that the recommended prop is 17 pitch and 13 diameter....but I can't find a 13 inch diameter prop?
Title: Re: Horse Power options for a 1976 170
Post by: akbridge on March 31, 2012, 06:26:43 PM
That prop will be fine.  The pitch is more important than diameter.   A smaller diameter will allow a quicker rev up and can help with hole shot.  The pitch determines the boat speed relative to engine speed.  I like this website: http://www.rbbi.com/folders/prop/propcalc.htm (http://www.rbbi.com/folders/prop/propcalc.htm) most gear cases use 2.0:1 ratio, figure a max speed of 40 mph, 10% slip and engine speed of 5250 rpm.
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on March 31, 2012, 09:20:06 PM
I really thought I would get 45 mph out of her. Oh well, I guess I will be better off having an all around good prop.
Title: Re: Horse Power options for a 1976 170
Post by: jsakat1 on April 01, 2012, 12:02:17 PM
I have a 130 on my 87 170, and the fastest I gotten is 46. I think the mounting on the motor has contributed to such a slow performance. But I redid the floor and transom, with no wood and I think it will be faster. The day that I put a 4-stroke. I was looking at a 115 yamaha, but weight wise is a lot. The 90 4-stroke looks like a better fit.
Title: Re: Horse Power options for a 1976 170
Post by: Fletch170 on April 01, 2012, 08:58:55 PM
I knew I wouldn't be building a speed machine, but I think the 115 yams 2 stroke is the perfect power for this boat.
Title: Re: Horse Power options for a 1976 170
Post by: Capt Matt on April 01, 2012, 09:09:49 PM
4 strokes are for barges and the retired lol
Capt matt
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