technical guidance on a mid 90s rebuild

[bob johnson]

ok, I have an Evinrude 1997 90 hp Ocean Pro, that i bought last summer with a slight knock.. I ran it and sure enough it does have a knock...it runs great, starts great..BUT has a definate knock... I knew it when i was buying it, but because the guy had taken so many trips with it while it had the knock and it never died, i took a chance..

but in the end I didnt trust it for winter time duck hunting use..so i bought a 1995 115 hp johnson Ocean Runner( almost same exact motor!!)

so I was keeping the 90 hp motor for misc parts, but am now thinking of rebuilding the 90, or at least tearing it down to check whats going on.

I found 1995 115 hp 60 degree block for sale, thats needs a sleeve...it is a bare block..

would it work, AND beworth while to get this block resleeved and bored and honed and sitting right next to my other motor and as i tear down the 90, start to reassemble the 115 with the 90 parts????

they have the same bore and stroke i think...the carbs are what i understand makes the 115 more HP than the 90..

and basically just have a rebuilt 90 hp!!!

I am thinking this way the over all process would be less time and it would be fresh in my memory on reassembling...

I have all but given up hope that the 90 has a simple easy fix KNOCK...

I am sure it will be the rod and crank..mayeb the wrist pin..

any thoughts????

bob

 

[Dhadley]

Re: technical guidance on a mid 90s rebuild

The wiring harness is different on the 95 vs the 97 but that can be overcome. You can use a 115 block and dress it with the 90 parts, no problem. Now, why does the 115 block need to be resleeved?

 

[JB]

Re: technical guidance on a mid 90s rebuild

You are guessing. Bad idea.

Find out what it is. Then decide what to do.

That is, unless you are simply thinking up excuses to do what you wanted to do in the first place.

 

[trendsetter240]

Re: technical guidance on a mid 90s rebuild

ok, I have an Evinrude 1997 90 hp Ocean Pro, that i bought last summer with a slight knock.. I ran it and sure enough it does have a knock...it runs great, starts great..BUT has a definate knock... I knew it when i was buying it, but because the guy had taken so many trips with it while it had the knock and it never died, i took a chance..

but in the end I didnt trust it for winter time duck hunting use..so i bought a 1995 115 hp johnson Ocean Runner( almost same exact motor!!)

so I was keeping the 90 hp motor for misc parts, but am now thinking of rebuilding the 90, or at least tearing it down to check whats going on.

I found 1995 115 hp 60 degree block for sale, thats needs a sleeve...it is a bare block..

would it work, AND beworth while to get this block resleeved and bored and honed and sitting right next to my other motor and as i tear down the 90, start to reassemble the 115 with the 90 parts????

they have the same bore and stroke i think...the carbs are what i understand makes the 115 more HP than the 90..

and basically just have a rebuilt 90 hp!!!

I am thinking this way the over all process would be less time and it would be fresh in my memory on reassembling...

I have all but given up hope that the 90 has a simple easy fix KNOCK...

I am sure it will be the rod and crank..mayeb the wrist pin..

any thoughts????

bob

A knock doesn't mean that the existing 90hp block is unusable.. It doesn't make any sense to me to buy that 115 block before you know what's wrong with the 90.

More than likely the block on the 90 will be workable with a rebore or honing which should be cheaper than buying the 115 block and getting it resleeved.

My advice, tear down the 90 first and see what you are dealing with. If you find a bad crank along with some bad pistons, rods and bearings it might not be worth rebuilding at all. At least then you won't have two blocks sitting on your bench with no internal parts!

 

[bob johnson]

Re: technical guidance on a mid 90s rebuild

I have no preconceived ideas....I knew that somewhere along the line i'd want to figure out what the problem was on the 90hp...

it looks great, but has a good audible knock...

I thought it might be something under the flywheel....but on the boat, under power, it sounds deeper and harder and sounds serious...

the compressions numbers are all good...

since I have a running 115 of the same style , and I like it...

that caught my eye when i saw the bare block for sale...

it is an auction and starts at $49.... so maybe it can be had cheap!

the guy says that the #4 piston ring broke and damaged the cylinder to the point it has to be resleeved.. to be used.

so i am only thinking, that I can get a REBUILD going, and ready so i have the option of using it for the 90 problem( it will probably be a rod-crank-piston issue I guess), which means a pretty in depth rebuild...

or use it for my current motor if i develop an issue with it..( then it is an exact replacement)

the wiring harness that came with my 97 , I am currently using with the 95!!

so I am covered there...I have both harnesses to my post 95 control!!

just brain storming if i will save anything in time and headaches...with a small investment in the bad BARE block

I havent taken the heads off the 90 yet and looked into the bores....

maybe i should do the piston to TDC and check for play...

I just saw the block today and tought id ask

thanks


is it true the blocks are identical????

are the ports in the bore the same???
bob

 

[Dhadley]

Re: technical guidance on a mid 90s rebuild

The blocks are the same as far as you can dress them both with the components you have.

 

[trendsetter240]

Re: technical guidance on a mid 90s rebuild

it is an auction and starts at $49.... so maybe it can be had cheap!

Hey 50 bucks is 50 bucks. You have two motors already that could use that block. Sounds like a reasonable purchase to me. If you don't end up using it, you can always re-sell it.

Cheers