1985 115 HP Mariner Project

[WinnipegBoatMan]

Hi All! Heres the scoop! I just stumbled upon a wonderful little project, a 1985 "tower of power" inline 6 115hp Mariner (s/n A728341), with T&T, oil injection unit, and full controls!
The story goes just like every other oil injection motor.. it failed! It failed and completely trashed 2 of the cylinders, i believe it was cyl. 3 & 6
I just got the motor this week, and today finally mounted it to a stand, and ready for a teardown to see the actual damage to the powerhead.
My question to everybody is... will it be worth my time to teardown and machine the powerhead block, and add new pistions/rings bearings? or part out the S.O.B and try to add some $$ to my pocket?

 

[OldMercsRule]

Re: 1985 115 HP Mariner Project

Hi All! Heres the scoop! I just stumbled upon a wonderful little project, a 1985 "tower of power" inline 6 115hp Mariner (s/n A728341), with T&T, oil injection unit, and full controls!
The story goes just like every other oil injection motor.. it failed! It failed and completely trashed 2 of the cylinders, i believe it was cyl. 3 & 6
I just got the motor this week, and today finally mounted it to a stand, and ready for a teardown to see the actual damage to the powerhead.
My question to everybody is... will it be worth my time to teardown and machine the powerhead block, and add new pistions/rings bearings? or part out the S.O.B and try to add some $$ to my pocket?

Either way: win win.

Sounds like you got it real cheap.

I don't personally rebuild as a general rule, as very nice runners with even cornpression are plentiful and very cheap in the Seattle/Portland Metro areas.

So it depends on how easy it is to pick up running towers in yer area, which will also dictate prices you will get fer the used parts from this one.

Good luck, JR

 

[Faztbullet]

Re: 1985 115 HP Mariner Project

I love the oil injection failure posts!!! Most likely you have a trigger failing and caused this as oil failure cannot take out just 2 cylinders on 6 cylinder model, even more unlikely is cylinders on are different carbs. Throw the aut-blend unit away and rebuild it(engine) it will last you several,several years if done correctly.

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

Thanks for the input!! I'm going to start this week on the teardown and get a better picture on this monkey.. lol

 

[Chris1956]

Re: 1985 115 HP Mariner Project

Overheat and/or detonation will take out cylinder 3 followed by cylinder 1, on those inline sixes. Rebuild will cost on the order of $350 if you do the work yourself. Don't forget to rebuild waterpump and fuelpump, clean all carbs, and perform link and synch, before running the motor.

 

[arsenalpsu]

Re: 1985 115 HP Mariner Project

I'm in the process of rebuiling my 1984 115hp right now. I bought 6 new pistons b/c my year the piston rings were undersided and prone to falling out causing the ring to rotate and break off. On 2 of my pistons the top ring was gone. I think it was aided by a previous owner over heating it as well. I got my pistons at a good price from Wayne (clamscasino) and a few other parts. Total cost was about 450 so for me is was worth it for me. Send me a PM if you want his contact number. He has also helped me with any questions as he does this for a living. He'll also do a block swap if you'd rather have him send you a rebuilt block for yours. Either way good luck, it's been a learning experience for me but not out of reach if you have mechanical sense.

Jon

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

You guys are great! Thanks for the input!! I'm getting my OEM manuals on friday to start the teardown! Cant wait to see the damage.. lol, i'll post some pics as soon as I can!

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

Well, I finally got a nice break in the weather and got the 115 on a stand for the tear down.

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

At this point the electrical is all off, and ready to split the power head from the mid section

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

The powerhead is finally off!! No problem at all gettin it to split off the mid section!
As I began to get the exhaust cover and baffle off, I got a look at the cylinders, and pistons. Its not what I had thaught at all! the #4 pistion is trashed. Its very badly scored. the rest of the cylinders didn't have "noticeable" scoreing from the exhaust ports. But that might all change once the crank, and pistions come out

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

The only thing left to do, is split the block and yank the crank.

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

Alright! Got the front of the block off, and WOO WEE! looks like some good and bad news!
First off the crank looks like its in good condition. I'll get some pics up after I pulled the crank and pistions out

 

[rodbolt]

Re: 1985 115 HP Mariner Project

I hate you fresh water boat guys .
in my area that simply wont come apart.
pay caerful attention to the exhaust diverter sometimes overheat cracks them and then bad things happen.

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

After I yanked the crank, I got the whole story of what happend to this poor TOWER OF POWER! Cyl #4 failed, and cyl#2 had a busted lower ring. Cyl#4 looke horrible! all 3 rings were stuck, and metal built up all around the piston. The top of the dome was worn down pretty bad. The cyl#2 was not too bad, but not perfect. The top of the dome too was worn, but not metal build up on the rings and piston. But it did have the borken ring. All in all, its time to get the block measured up to see if it can be saved, or if i need a new block??

 

[arsenalpsu]

Re: 1985 115 HP Mariner Project

Feel in each cylinder with your hand, if you can't feel any of the marks with your finger nail you'll just need to hone her. If you can feel any you'll need to bore and get some oversized pistons. If you can't feel any marks I wouldn't worry about them 100% round, remember what you're doing here - not building a racing boat, just want to get her going again.

 

[WinnipegBoatMan]

Re: 1985 115 HP Mariner Project

I managed to get the block to an outboard machine shop here, just outside of the city. Its pretty hard to find a machine shop that will bore these inline 6 blocks. But! I found a place that would, and the good news is that Cyl#4 is the only cylinder that needs to be bored over by .015.. Yippy! The over 5 cyl will get a good hone job..
The good news doesn't end there! The machine shop can also get me a deal on 2 new piston kits(cyl#2 had pretty bad detonation damage as well), they are going to steam clean the block, polish all the block mateing surfaces, check the straight edges, and get me a powerhead gasket kit, all for only a few hundred $$ not bad eh?
I'll post some pics after I get the block back

 

[arsenalpsu]

Re: 1985 115 HP Mariner Project

Does that few hundred include the pistons? You might want to consider getting all new pistons, as i stated before the ring pins are prone to pushing into the pistons on these old low domes-they might look ok now but in a year or two who knows. Plus the 2 ring semi-keystone are superior to the 3 ring system, some shops I know will only rebuild using the 2ring system. Once that ring ping pushes in or out your ring can now rotate and will eventually break. Just some food for thought. BTW boring that piston is the only thing you couldn't do in a shed, when you say a few hundred, is that 200 or 450? If it includes all the parts and pistons it's not a bad deal, if it's another few hundred for the parts I would have rather done it myself.

 

[daveswaves]

Re: 1985 115 HP Mariner Project

I managed to get the block to an outboard machine shop here, just outside of the city. Its pretty hard to find a machine shop that will bore these inline 6 blocks. But! I found a place that would, and the good news is that Cyl#4 is the only cylinder that needs to be bored over by .015.. Yippy! The over 5 cyl will get a good hone job..
The good news doesn't end there! The machine shop can also get me a deal on 2 new piston kits(cyl#2 had pretty bad detonation damage as well), they are going to steam clean the block, polish all the block mateing surfaces, check the straight edges, and get me a powerhead gasket kit, all for only a few hundred $$ not bad eh?
I'll post some pics after I get the block back

If they are Wiseco pistons make sure the machine shop gives you an extra .001 on the cyl that the wiseco is going in. If they are original merc pistons or Persan pistons bore to spec.

 

[mke039]

Re: 1985 115 HP Mariner Project

Thanks for the awesome thread! I am going through the same thing, rebuilding a used engine. Your pictures and explainations are very helpful. I am looking forward to how you get your new pistons/rings back in the block!

 

[szealuss]

Re: 1985 115 HP Mariner Project

Good thread, Keep posting on progress. I got a '67 110 SS merc from my Dad in Virginia thats has only seen freshwater, I brought it down to central Florida east coast where i mostly run saltwater. This thing looks and runs great, putting it on my ski boat but has no t/t. could use advise on that, but another thread. Point is I would mix fuel from here on out. Have a '85 150 on my offshore and had to go through it and not so easy as freshwater motors. This '67 looks like new cuz it never ran salt water through it. Shame im gonna get her feet wet.