1974 170 rebuild

[Corynelsonflkeys]

Hey guys! I got my first 170 a little over a month ago, I traded a '62 13' Whaler I had been ripping around on for the past year. I put the whaler through hell taking it offshore down here in the keys all winter so it was in need of some fixing so the trade was to my benefit in my opinion but the 170 needs PLENTY of work as well. It came with a 1997 150 Evinrude with a completely fried harness from the regulator shorting out and a deck that had "just been redone and only needs paint." I picked the boat up at night and tried to look it over as much as possible without the mosquitoes of Big Pine carrying me away. I woke up early the next morning before work and realized the deck was done terribly and used honeycomb laid on top of the original deck with plenty of dry spots in the glass that were not dense with resin I was mildly defeated but have wanted to lay a new deck for the learning experience for quite some time. A month later I ordered a used harness and reg off ebay, chipped off the burnt plastics, put some seafoam in the heads, changed the plugs and it started right up first crank.  didn't think i'd actually get it to run. It's been raining here all month but I was getting antsy being cooped up so I took her down to the ramp for a little sea trial before I start the deck. Rick told me the 150 would be too much and sure enough, it was! I had absolutely nothing in the boat so it was as light as could be, blowing 25 and scary as hell up in the "tower". I did a few laps around the island with plans on having to swim back but luckily everything went great besides getting pelted with rain. So now time to start the deck plan and tinker with the engine.

I'm still unsure about the 150. Do i sell it and find a 115 or just keep it until it dies and then invest in a newer 4stroke. ...An answer i will have when i can afford a new engine.
The tower is getting turned into a lobster spot in the bay because it's down right frightening to drive from in any waves or chop. 

Now for my question to the wise..

How much structural support does the cap provide? I don't want the casting deck nor do I want the sides that come down to the deck. I like seeing bare hull and was thinking about just adding supports to support the cap down to the deck similar to typical commercial boats or most of the 220'

[mshugg]

Congratulations.  The 170 is a fun and capable boat.  I had a 1985 as my first “offshore” boat.  I fished her hard and she took everything.  It’s perfect for the keys.

Sell the 150 and get the lightest 90-116 outboard that you can find on her.  The 150 is too much weight for the boat, and she doesn’t need that much power.  Honestly, you could get away with a 70.

As for removing the liner, it is a lot of work.  I did it on my 200 CCP, and it payed off weigh extra space.  The liner does add structure, so you will need to add some support for the hull sides and cap.  Here’s what I did:



You won’t need to use as many stiffeners as I did, maybe three each side. If you’re happy with a workboat finish, you can save yourself some fairing on the hull sides.  Only you can decide if it’s worth it.

[RickK]

When I bought my 170 it had a old merc straight 6 and the decals said 150. That thing would fly - when you stepped out from behind the windshield at WOT you got an instant facelift.     After some research (during the infancy of the internet) I found that the serial # off the engine proved it wasn't a 150, so who knows what the PO had done to it. She was fast though. This was before personal GPS existed also.
So now you know what a boat with too much engine (and weight) is like - something to pass on to the next person that asks.  If you can find an old Merc tower of power 115, that is the style engine the boat was designed for - the mounting brackets were thinner and the engines were light.

Cutting the liner out is very simple with a jig saw with Sterling blades. If you're going to leave the cap, as Mshugg said, you'll need to support it somehow. There are plenty of examples in the forums of this - I would think the Flatback forum would be the best place to look because they didn't have liners.  You might also look in the "Other Classic Rebuilds" forum and look at what the Proline guys have done.

[boatnamesue]

I'm still unsure about the 150. Do i sell it and find a 115 or just keep it until it dies and then invest in a newer 4stroke...The tower is getting turned into a lobster spot in the bay because it's down right frightening to drive from in any waves or chop. 

The dry weight specs I found on the internet for a 1997 Evinrude 150 is 375lbs, though I'm not quoting this spec weight directly from a '97
Evinrude-published service manual, therefore I'm not 100% this weight is accurate.  However, if indeed your engine's dry weight is 375lbs or weighs in this general vicinity, then its dry weight is exactly the same of a Yamaha 115hp of the same year....and this weight I'm 100% sure of.

I mention the above because if your '97 150 does weigh the same as a Yamaha 115 then the engines "weight" was not the cause of the scary ride you experienced.  I know this from experience because I have a '98 Yamaha 115hp on my '76 170, and at WOT there isn't anything of the boats performance that would cause me concern for my safety...and I'm a safe boater.  Now I would never knock a guy like Rick, he whom has forgotten more AS details than I'll ever know.  I do agree with Rick that hanging a 150 on an AS 170 is too much motor.  BUT, I believe the aforementioned statement is a generalization...it's not fitting to all 170's and certainly not fitting to every operator of a 170 with a 150hp hung on the transom....meaning the hp of a 150 hung on a AS 170 would be too much power for the average boater.

In the case of your hull, the 150hp, and with that half tower...I'm guessing just by the construction of the tower and the poor condition of the interior hull that the previous owner did not consider or even care what effect the tower would have on the hull's COG....and no doubt with the tower's location being so far forward the original COG has moved forward, which would completely throw off how the hull normally performs while underway in heavy or calm seas.  Also and aside from the forward location, the base of the tower is way too high, at least from the pics it looks higher than the gunnels.   This excessive height alone would throw of the COG.   I have plans to install a half tower in my 170, but at a base height of 13"-15"....the base of your tower looks to be 2.5'-3'!!  Then add in the towers location being too far forward is a double whammy.  Geez, I bet it was scary.  Assuming the motor dry weight is 375lbs, if the Evinrude weighed 100lbs more like current F150's then the tower being so far forward would make sense....in order to compensate for the added 100lbs aft.

So what I advise doing before you even consider ridding of the 150hp because you believe it to be too much power....you stated you plan on ridding of the tower, so I'm assuming this means you'll be installing a typical center console.  If so and after installing this console, rig the console with the evinrude controls and take her for a run in CALM conditions.  I'm reckoning you'll have an entirely different experience, a more comfortable one because you would have restored the hull's natural COG by removing the tower. 

Other than having to replace general maintenance engine parts (gaskets, water pump, fuel pump, etc), another thing to consider is that if you've found your engine to be in good shape, then think of the engine as a gem.  2 strokes in good shape, well maintained, and reliable, are very hard to come by these days.  People tell me all the time I should rid of my '98 2 stroke for a newer 4 stroke.  My response is always the same..."Why?  It's very reliable both starting and performance, it's got more low end than a 4 stroke, it's easier to mechanically troubleshoot than a 4 stroke, and most importantly I can perform all maintenance and repairs myself without the need of a computer program."  Just something to think about if you find that your engine is in good shape, just needed some TLC.

[knightfishin]

Congrats on the 170, I've owned mine now 20 years best boat I've ever owned I have a 1986 rebuilt Johnson 70 on the back of mine and it flies it will due 30 knots easy with a 17 pitch prop with 3 adults I'm really happy with it.  The 70s also great on fuel easy on the wallet, the Yamaha 90 is also a great option its actually lighter than the Johnson 70, good luck with whatever you do have fun.       

[matt1978E37]

Looking like some one is gonna get itchy.  Hey i drive down to Stock Island every 2 weeks for work.   I will be heading back there soon.  If you want to get together and talk 17's let me know.  Im redoing the floor at my house up in Pompano Beach

matty 

[RickK]

Looks like you have a good start Matt - have you started a rebuild thread of your own?

[matt1978E37]

not really.  not enough expendable time. 

[Corynelsonflkeys]

Well haven't had much time lately but i've got a little progress done over the passed couple months. We have a baby on the way and just moved into a new house so it's been tough to get time but this is what i've got done so far.

Day 1- I ripped the tower and box out. Mainly so i could fit the damn thing under the house.

day 2- Took the floor up and as much of the cement type bonding agent they used to seat the deck to the stringer.

Day 3- Finished chipping away cement. I call it cement because it's pretty much rock solid and hard as a rock.

Day 4- Took a saw to the tops of the stringers and started cutting out foam

Day 5- Spent most of the day pulling out foam and the rotten wood that was glassed to the inside of the stringers. (the bulkhead that runs across had no bottom to it and left the stringer completely exposed to water) and also has a sheet of ply in it  >:|

Day 6- Probably just stared at it for a few hours and wondered if i was in over my head at this point.

Went to see some friends at SeaVee and got all the materials i would need for the deck and transom. Well the bulk of what I needed. Ended up getting a full roll of 1708(150lbs), 5 1/2'' 4x8 sheets of foam, 4x8 sheet of 3/4'' Coosa and a few buckets of poly resin.

Made an order with land and sea, got some formula 27 for fairing, some Petit paint, few rolls of cloth tape, couple resin rollers, all my through hull fittings, gas cap, gas vent, bow and stern chocks, pop up cleats, pie eyes, deck hatches, bilge pumps, rod holders, bait pumps, battery switches, switch panels, and i'm sure a few other things I forgot.

So i've spent most of what i plan on spending or at least the bulk of it. Now it's just hours upon hours of labor. Slow season is about to start here in the keys so I'll have quite a bit of down time before the baby comes hopefully!

Day 7- Took a chainsaw to the transom and removed as much of what was left on the skin with chisels and a hammer in under 4-5 hours total.

Day 8- Made a template and cut the Coosa to fit the transom how i plan to have it.
and now, I'm going to sleep.

Feel free to give me your input and insights on anything and everything! I'm turning 25 tomorrow so I appreciate all the wisdom from you older guys I can get!

[Corynelsonflkeys]

[RickK]

That's a lot of progress!
Tips:
You'll need about 18" exposed from the inside of the transom on the stringers and liner so you can beef up the transom skin, set the core and then glass in the core using 3 layers with 4, 8 and 12" overlaps.

So your boat will drain when you pull the garboard plug after the rebuild:
Here is a link to where I explain the thought of the PVC pipe
http://classicaquasport.com/smf/index.php?topic=13148.msg133124#msg133124

Here is a link to where I show what is actual problem
http://classicaquasport.com/smf/index.php?topic=13148.msg133556#msg133556

Here is a link to Hawgleg's rebuild that shows the PVC pipe installation to keep a drain at the new low point of the boat
http://classicaquasport.com/smf/index.php?topic=13148.msg134262#msg134262

[mshugg]

Looks good.  That new transom notch should help keep water out of the boat.

[Corynelsonflkeys]

Okay so I laid 3 sheets of cloth, staggered at 4, 8, and 12 she’s solid she’s solid as a rock again. Next is to lay in the coosa board. Rick, what would would the best process be to sandwich it to the outer skin be? Mainly what filler should I use? And when mixed I was going to use a trowel to spread to ensure no hollows, yay or nay?

[Marcel4t]

I just did this...check out some of my vids on my build.  I used epoxy with cabasol to make "peanut butter".  If you use a trowel, go in one direction, probably vertically, so air bubbles can escape.  I didnt do that, but someone recommended I do that on my vid. 

[mshugg]

Rick, what would would the best process be to sandwich it to the outer skin be? Mainly what filler should I use? And when mixed I was going to use a trowel to spread to ensure no hollows, yay or nay?
[/quote]

Use epoxy thickened with fumed silica (cabosil) to a mayonnaise consistency. It’s also a good idea to use a knotched trowel to apply the glue.  That way you get consistent thickness and it’s less likely that you’ll have voids.  Some people also put in a layer of CSM and bond in your transom core while still wet.