Bought my first boat to cut, gut and rebuild from bow to stern, including engine. Killed my back and suffered the wrath of the fiberglass demons

[Scott Danforth]

Grew up with Mercs. Some older johnnyrudes, some Atwaters, Mac's, Hiawathas.

The Mercs always had more power for a given rating.. rating was at 3/4 throttle and above that was "reserve". At least that was the story I got at the time

Dad had a buddy (Merc and Tecumseh contact) do some work on the 50hp 4-cylinder on the old dunphy. After that the boat went from 34mph to about 38mph. I was 5 or 6 at the time, however I remember the smile on dads face. No tach, however it screamed magical music at WOT

 

[tpenfield]

I'm a Mercury guy . . . but it is all about the condition of the engine. Not sure how you could test it. Maybe a compression test if power can be hooked up to it.

It depends on your budget and how much you are willing to put into it after the fact. In about 1979 (ish), Mercury went from carbon steel drive shafts to stainless steel, which brought them on-par with Evinrude & Johnson for salt water use. You are fresh water so no worries.

For a visual inspection, I'd take a good look at the lower unit to see if it has corrosion. I tend to view every motor over 20 years old as a project.

If you had $2K+ to spend on a motor, you'd might be up a few notches on the scale of project vs. usable.

 

[stresspoint]

i too have had merks including a 90 4stroke which IMO was one of the best merks i have ever had only because it was a Yamaha power head.

the motor i had years back was similar to the one you posted a pic of 65 hp i think , engine block is still up the shed ,as in pic, ,ended up stripping it for parts as it had no PTT so it was not suitable for my application , only reason i kept the long block is because it was had a full rebuild , not sure what other bits are up the shed for that motor ..

the 85 hp Johnno in the pic is a monster of a motor for a 85 , i recon it got rated lower that the actual output , some say the early motors were rated at th motor rather than the prop as the are now , not sure how much truth there is in that , but i have had 140s that don't make the power that 85 has.

 

[todhunter]

Is there any recommendations on a good foam? Is there a good pourable closed cell foam that would work well?

I used 2 lb density pourable foam from US Composites. I bought all my glass, resin, gelcoat, filler, and foam from them. If you can have it shipped freight (to a place with a loading dock), you can save some cash.

 

[Lou C]

I also used the 2 part foam on mine don’t remember the brand because it was so long ago. When you pour it the temps have to be at least about 70 degrees and you must do it in such a way that the excess can escape or it will pop the deck you just installed right off. I poured mine before installing the deck & let it cure. Then cut it even with the top of the stringers before laying down the deck. What I learned was that it added a lot of stiffness to the structure.

 

[TripleJGraffis]

I'm a Mercury guy . . . but it is all about the condition of the engine. Not sure how you could test it. Maybe a compression test if power can be hooked up to it.

It depends on your budget and how much you are willing to put into it after the fact. In about 1979 (ish), Mercury went from carbon steel drive shafts to stainless steel, which brought them on-par with Evinrude & Johnson for salt water use. You are fresh water so no worries.

For a visual inspection, I'd take a good look at the lower unit to see if it has corrosion. I tend to view every motor over 20 years old as a project.

If you had $2K+ to spend on a motor, you'd might be up a few notches on the scale of project vs. usable.

The pics above are the only ones I have to go off of currently. He did run a compressing test and said all 4 cylinders were 145. Not sure what that means or if it's a good number. I can scrounge up a couple thousand. I'm not sold on this unit yet.

 

[TripleJGraffis]

I also used the 2 part foam on mine don’t remember the brand because it was so long ago. When you pour it the temps have to be at least about 70 degrees and you must do it in such a way that the excess can escape or it will pop the deck you just installed right off. I poured mine before installing the deck & let it cure. Then cut it even with the top of the stringers before laying down the deck. What I learned was that it added a lot of stiffness to the structure.

That's a good idea! I was planning on installing the deck first and pouring into drilled holes. I like your idea alot more! Less drilling and patching!

 

[kcassells]

That's a good idea! I was planning on installing the deck first and pouring into drilled holes. I like your idea alot more! Less drilling and patching!

If you use that method make sure you epoxy the top to seal the open/cut foam cells to prevent moisture from getting in. Expansion foam is closed cell product.

 

[tpenfield]

Speaking of Plywood . . . About 20 years ago (oh my . . . how time flies) Most boat companies (that use wood) went to a treated plywood to resist rot.

https://inlandplywood.com/products/perma-panels/

In addition to Perma Panel, there is also a similar product called Greenwood XL.

Not sure if you can get any in your area, but worth considering.

 

[Lou C]

A couple of old pix from 2006. Not the greatest job but my first one. The dark framing is Mahogony, which is very rot resistant. I would coat the foam with epoxy if you do it this way. The gas tank mounts were cheap pine that were all rotted and let the gas tank start to move around! That Mahogony was hard to cut but seems as rot resistant as epoxy coated dimensional lumber.
I pull up the cover over the tank every few years to check the wood and fuel lines, it still looks good, 18 years later. So that lasted longer than the factory work!

 

[kcassells]

I just like the direct bonding of the foam to underside of my plywood deck.

 

[racerone]

Pictures in post 231 show a 1976 / 77 motor .----Based on the decals.

 

[TripleJGraffis]

Got back in the saddle today. Got a multi purpose tool recently and used it for the first time...... also was my first time using one so after trial and error and 2 quickly broken blades..... that bad boy really gets a job done! I removed the remaining bow seat bases as well as one of the Steen seat bases. That little tool made real quick work of it! Found more foam in the back. (Sigh). I had planned to put swivel seats back there upon rebuild.... but I guess it'll be more foam and then I think I'll Box it all in and just install a bench along the back of the boat. I do believe I got s little carried away with that tool abs went through the hull. My buddy found what appears to be a 12 inch Crack back there.... but I am wondering if it was really me.... because that would explain all the water logged foam back there. Idk.... doesn't matter.... I'll eventually be taking it off the trailer and patching the hull up anyways... I just add that to the list. Anywho.... I'm beat... gotta work 46 hours this weekend so I'll try to get back at it on Monday. Take care everyone!

 

[stresspoint]

what's happening Op , progress report would be good .

 

[redneck joe]

Yeah don't bait us like that we need updates!!!

 

[stresspoint]

i hope Op has not abandoned the build like others do at this point.

 

[The Force power]

i hope Op has not abandoned the build like others do at this point.

And he certainly does not want to hear; I told you so

 

[ScottinAZ]

geez, guys, its barely been a week since his last post.. some folks have lives outside of boats (poor suckers).

 

[stresspoint]

geez, guys, its barely been a week since his last post.. some folks have lives outside of boats (poor suckers).

calm down we just digging to get the Op back to see what progress he has made .
this bloke aint going to give up that easy , he is in for the long haul is what i can see reading his posts .
poor suckers thats funny.

 

[Lou C]

then there’s us of a certain age who are semi retired who got no excuse!
My projects:
Rebuild spare Cobra trim rams
In fall fix rotted wood in coaming panel & finally install the new control I bought….10 years ago! If I get really ambitious I will also replace the helm steering unit & cable while it’s all apart.

Then there’s Jeep projects the restoration of the old 1998 Grand Cherokee 4.0 liter & freshening up of the 2007 Grand Cherokee with the mighty 5.7 Hemi…

Alt least my complete rebuild & modification of my old 1994 Load Rite roller trailer is done! Now it’s finally the way I wanted it. 6,000 lb axle 225/75-15 tires & 12” surge brakes. Lowered crossmembers to get the boat as low as I could. Long tongue to keep the Jeep tires out of the salt water.