Fletch's 1976 170 Rebuild

[c master]

Fletch - this is completely my opinion, and as you know, "everybody has one".   I defer to Gran, SeaBob, Circle Hooked, Fission, etc:  Please correct anything I've said here...I'm not a mechanic...and you guys are all far more knowledgeable than I.

Anyway:
 
My 170 is powered by an 88 horsepower, 1996 Johnson SPL 2-stroke.  I'm happy with it, but it's just a simple motor...not even Variable Ratio Oiling - I have to mix.   I believe in '96 it was rated at the prop.  Today, most HP ratings are at the powerhead, meaning that with a "60" you don't have 60 at the prop.   But even if our motors were rated in the same way, I'd have 32% more HP.  In this case, the actual difference is probably north of 36%.   I don't think 60 is enough.

Having said all that, if I were repowering my own boat, I'd still go UP in horsepower (from my 88 to maybe 115).  That would put me close to DOUBLE a 60 hp.  It's not that I'm a speed junky...Texas bays have this weird wavelength to the chop, so it's often uncomfortable for a 17-foot boat to go 40 mph anyway.  In my case the extra power is more about lower-end control, staying on plane with 3 fat guys aboard, popping up out of shallow water, pushing into the occasional headwind or chop, pulling the occasional tube rider, burning less $4.00 gas, etc.

Bottom line:  If money's tight, why not find a lightly used, young 2-stroke...with more horses.  I could see that 60 on a 17' aluminum boat but the 170 will be a better boat with 90+.

Also, I question the seller's stated engine weight.  I think it's closer to 250 without controls.  Maybe a little more.

[RickK]

Fletch - this is completely my opinion, and as you know, "everybody has one".   I defer to Gran, SeaBob, Circle Hooked, Fission, etc:  Please correct anything I've said here...I'm not a mechanic...and you guys are all far more knowledgeable than I.

Anyway:
 
My 170 is powered by an 88 horsepower, 1996 Johnson SPL 2-stroke.  I'm happy with it, but it's just a simple motor...not even Variable Ratio Oiling - I have to mix.   I believe in '96 it was rated at the prop.  Today, most HP ratings are at the powerhead, meaning that with a "60" you don't have 60 at the prop.   But even if our motors were rated in the same way, I'd have 32% more HP.  In this case, the actual difference is probably north of 36%.   I don't think 60 is enough.

I could be wrong but I think you have this backwards - old engines were rated at the head and new ones are rated at the prop.  
But I agree and think that 60 is not enough also.

[Fletch170]

Along time ago, I was told by an OEM Yamaha dealer that the HP on 2 strokes was measured at the prop, and Fourstrokes were measured at the crank. I was told that on an outboard you lose about 15% through the drive....I dunno.

I really like the idea of a 4 stroke for obvious reasons, but I just dont think I can afford one in my price range. However, I like the HP to weight ratio of the two strokes. Even a new-er 2 stroke 90-115 is going to run 4-5 grand. Agian, if anyone knows a motor for sale, please let me know. I just bought a house and I am paying for my wedding "we" are paying for our wedding.....cough cough. Needless to say, my Fiance is thrilled I bought an old boat. HELP!!!!!

[gran398]

Fletch,

An old strong 115 Yamaha V-4 two stroke would be a ball o' fire on you're ride. You should be able to pick up a good 'un for $1800 or less.

Don't be in a hurry. Still a buyer's market in this economy. Think broke.

Best to you and your new bride...and hang right here

[Fletch170]

Thanks Gran!

Any decent places to look for used motors besides FleaBay? My local Craigslist usually turns up 1982 Chrysler motors with a huge piece of tri-hull crap attached to it.

-Fletch

[MJB1]

Fletch,

I just finished a rebuild on my 1976 170 a couple years ago, you might actually find some pics on a thread or two.  Concerning the deck, I did raise my deck about and inch above original.  I did this after cutting the entire deck out, repairing the stringers which had delaminated and then also re-foamed.  On top of the stringers after regalssing those in following the new foam, I added 3/4 marine plywood which resulted in an increase of about an inch.  THe deck I used 1/2 marine plywood and glassed both sides with heavy mat (forgot the grade) and then glassed the new deck in place.  I saved about an 1 1/2" of the original deck around the outer edge of the deck so I could use that to anchor the new deck.  I re-used the fuel tank coffin and re-glassed that in place.  I was undecided on running a PVC tube or using the original trough which I had saved.  I opted for the original trough, I found a PVC tube was going to have some pretty tight bends which I didn't want.  Plus I was worried about water in the tube/bilge.  I replaced the original fuel tank with one I had manufactured from a place up north (they had done 170 tanks and I think it was one someone here had recommended) which is a 26 gal tank.  As for the transom, well I can't say for sure but I would think that you probably do have some rot in the core just by looking at the pics.  If your planning to do a bunch of work and replace the deck etc you might as well re-do the transom.  I also re-used the transom trough and glassed that into my deck/transom but I did only go with 2 drains vice the 3 it had.  All in all my drain holes are about an 1 1/2 higher than original (I was worried about draining).  With the new transom I did add height to the sides so it is not uniform like original -- I have the notch for the engine, then it steps up about 6" then it ties into the gunwale.  Hard to explain, but if you'd like a pic I can dig one up.

[MJB1]

Fletch,

One other thing, I agree with the others on HP -- I originally was thinking 4 stroke but the weights were a concern because I wanted to keep things light. I opted for a used 2 stroke 90HP Yamaha which I have run the past two years.  I'm not a speed freak but I will say it is a perfect match and it really does sip fuel.  I would not go with less HP than 90 - my opinion.  Now you have to factor in weight difference between a 90/115 2 stroke and a 90/115 4 stroke -- big difference in a small boat like a 170.

Hope this helps.

[Fletch170]

OH DEAR LORD YES, Please send me anything and everything! Do you have a thread with pictures on here? ANY help would be greatly apreciated!!!!!!!!!!

[MJB1]

I think this will get you to the thread, if not try searching under my "other" name which it was originally listed  "MJB" and look for 76' 170 Rebuild.  I hung a bunch of before, during, and after pics in that thread.  For some reason I couldn't reset my original password so instead I just signed up again.

http://www.classicaquasport.com/phpbb3/viewtopic.php?f=2&t=2579&st=0&sk=t&sd=a

[RickK]

I think this will get you to the thread, if not try searching under my "other" name which it was originally listed  "MJB" and look for 76' 170 Rebuild.

I can fix the p/w but not sure if I can merge the 2 accounts.  Should have alerted me to this problem when it happened - I've been the only one running this place for many years. I have CB doing a great job helping now as a Inter Galaxial Super Mod  
Seeing that you only have 5 posts on this acct it won't be a big loss of posts - want me to reset the p/w on the MJB account?  PM me.

[MJB]

Original account is back, thanks.

[Fletch170]

Hey guys, so what I'm reading, it seems like anything structual, 1808 is the way to go?

[slvrlng]

1708 or 1808 45 degree biaxial. Either will work, the 1808 is a little harder to wet out because its thicker. I used one layer of 1708 on the bottom of my coffin cover over the divinycell and now its as strong as a diving board! The divinycell or nidacore is not strong by itself. The combination of bonding between the layers is what gives repairs their strength. That is why on structural stuff I like epoxy because of its superior secondary bonding ability. Most poly repairs only have a physical bond "think sanding scratches". Vinylester is kind of in between the two but it still has a short working time compared to the epoxy. Plus nothing else sticks to old fiberglass like epoxy.

[Fletch170]

Do I want the 1808 or 1708 with mat on the back assuming I'm doing the transom.

I'm assuming the 1808 is a little stronger, but heavier I'm assuming?

[slvrlng]

Here is a link to a thread from classic Mako that should answer most of your questions. Thanks ChuckB for finding it!

http://www.classicmako.com/forum/topic. ... fiberglass