Reliability of 1998 25hp EH

[rp3703]

I picked up a 25HP that looks to have overheated badly. From my calculations, it would cost around $1600 to get it running again. I've noticed that there don't seem to be too many of these motors on the used market but there seems to be quite a lot of ruined power heads. Are these just bad motors? I can't find any reviews on it.

 

[racerone]

Folks today do not maintain / operate motors like in the past.----Perhaps scared of the $100/ hr stealership service department.---They do not install new impellers every 5 years or so.-----Do not run with the correct propeller.-----Run with wrong oil / wrong ratio etc.-----There is nothing wrong with the design of the motors.

 

[rp3703]

Lack of maintenance can apply to any outboard model but I still see plenty of older Johnson’s on the market. I found 1 used 25hp late 90’s Mercury and lots of power heads with scored cylinders.

 

[Scott Danforth]

a well maintained motor is reliable as he#

a neglected motor run hard and put away wet (without any of the maintenance racer mentions) will die.

most motors dont die, they are murdered from lack of preventative maintenance

 

[racerone]

People invent new ways to damage motors every day !!-----Found impellers on 2 motors this past year.----Worst I have seen for a while.-----A 1998 Johnson and a 1988 model 60 HP Johnson.-----Both had impellers that had been run dry.-----The 98 model was a complete mystery and I can only surmise that the ---REAL ESTATE AGENT ----Demonstrated / started the motor dry multiple times for prospective buyers of a summer place.------

 

[rp3703]

Maybe this is a better question. If I were to spend the $1700 or so to install a new power head, new water pump and replace the various other melted or broken electrical parts, what else should I be looking out for on a motor that has suffered light scoring in both cylinders and given the melted plastic parts throughout, has been through a pretty extreme overheating event?

 

[racerone]

I guess it depends on your location.----Lots of good used motors available for less coins.

 

[Scott Danforth]

for 1700 I would find a better maintained motor to start with.

 

[racerone]

3703----Your location ?

 

[rp3703]

I live in Nashville TN. Deals on outboards are not too common around here lately and I'm NOT looking for something so old that they don't sell parts for it anymore. I already had to scavenge to find parts for the 83 mariner 25 to get it running again. I picked up a 96 Johnson 25 that I had to rebuild the lower unit on but at least you could still get OEM parts for that one. All of these motors reside at our lake house in Ontario Canada and I was kind looking for a third motor as a back up in case one of the other two decides to crap out on us one year. I picked up this Mercury as a winter/spring project but if the motor's not worth the cost that would be required to get it running again, then I'll just part it out and wait for the next deal to come along.

 

[racerone]

Roughly where is your lake house in Ontario ?----Parts for many newer motors is becoming an issue today.

 

[rp3703]

It's north of Toronto by three hours, on the French River. We have a couple of V-hulls we flip over when we're not there. Of coarse we didn't get to come up this year. MOD EDIT

 

[rp3703]

So upon further inspection, it looks like the previous owner ran this motor with a disintegrated impeller. This caused a catastrophic overheating that must have caused the pistons to expand to the point where they scored the cylinders. Almost anything made of plastic or rubber connected to this motor is melted.
I have found a used powerhead for $760 on Ebay that still measures 125 in both cylinders.

90885A88 Complete Powerhead for Mercury Mariner OUTBOARD 20 25 HP 2 Cylinder for sale online | eBay

Find many great new & used options and get the best deals for 90885A88 Complete Powerhead for Mercury Mariner OUTBOARD 20 25 HP 2 Cylinder at the best online prices at eBay! Free shipping for many products!

www.ebay.com

That, a new water pump and a few other new parts and this motor should be good as new for around $1200 total including the initial $100 I bought the motor for. To me this seems like a pretty good deal on a later model electric start motor. What do you guys think?

 

[The Force power]

So upon further inspection, it looks like the previous owner ran this motor with a disintegrated impeller. This caused a catastrophic overheating that must have caused the pistons to expand to the point where they scored the cylinders. Almost anything made of plastic or rubber connected to this motor is melted.
I have found a used powerhead for $760 on Ebay that still measures 125 in both cylinders.

90885A88 Complete Powerhead for Mercury Mariner OUTBOARD 20 25 HP 2 Cylinder for sale online | eBay

Find many great new & used options and get the best deals for 90885A88 Complete Powerhead for Mercury Mariner OUTBOARD 20 25 HP 2 Cylinder at the best online prices at eBay! Free shipping for many products!

www.ebay.com

That, a new water pump and a few other new parts and this motor should be good as new for around $1200 total including the initial $100 I bought the motor for. To me this seems like a pretty good deal on a later model electric start motor. What do you guys think?

I've been following the conversation and I don't know what a motor around your area is going for but I sold an Merc. similar age same HP for $1,050.00 CAD( with electric start & Controls) here in the Toronto area.
So....in my situation: I would not pursue

 

[Faztbullet]

Look on FB marketplace...there is a 98 25hp Merc electric for $1200 OBO in Hendersonville.

 

[rp3703]

Thanks, Faztbullet. That would have been a pretty good find for a boat and motor. Unfortunately, when I went to check it out, the motor only had 80 PSI in both cylinders. Oh well, I'm in no hurry. Don't need a running motor until June.

 

[flyingscott]

Rebuild what you have yourself. That is a Mercosil block so it can be bored and the rebuild kits are available for it.

 

[rp3703]

That was my plan at this point. All I need is a decent cylinder half of the block, new pistons and rings. New piston and ring's will run $300 and I can't decide if It's better to buy a used block like this one


https://www.ebay.com/itm/EF6A11618-25-HP-Mercury-6017454-Cylinder-Block-Assembly-PN-8196A3-Fits-1980-1989/113723480670?_trkparms=ispr%3D1&hash=item1a7a729a5e:g:5PEAAOSwvlhbKXpR&amdata=enc%3AAQAFAAACcBaobrjLl8XobRIiIML1V4Imu%252Fn%252BzU5L90Z278x5ickkAgU0umhwUTmgTFbE5cu7zWF1miV%252FqoEbRzFr3FHhZw4dUX3oLEgnFfRCrnxz1SfDSL7zfHsGitVOhsQGhcp2qD9SmlUiF9x7xs6q8gCUEIoAw4m%252BlNfhpkQ07s73ZYocNlSYF19WYuScz827hSy%252F%252B4ZjCGBEq4C1KsoWwi6LRKVleCCawDS0Jy3Wv7RWaMltuU%252FHbZL3YJpycWQ%252F2Dnc3cqqeDIPZdZUQHQhtJmlBy0aOw7PdBQNpiddvGUIUWwu1BPGnhcD5lvgVktbMaKBiY3j8IC9pp8mME4uW%252BfZwfm4hbKqVD0Ndbq0pJtl1jJww5BsH0PKp%252FRwLNONyV0x7waPpEYemC7tLE2d5DojpY6S%252BZdLSxQv6lrkgl2VhLuRtnD7uWhaLjqsUyKZxLniYGcWzmEEqiyT3w5Pw50BnaiMTbpDW3%252B02CV1IwoNzVLVMXT0Hm0SCL4YeBzWVsZQoBH%252FKdpOO5BUIrLtXGMOO1bvweri4%252B8%252FFy29ORzOLZbEH8HJ3ywft4Wb6Va2iN9Vpv%252Bj5pOETQH3wVtrHVevX8oDXqMoWg2paPHdnqKrVAfE3HS62Rn7T0KIRyyQ09ZWPzDJeBGDm8ylvoSfcZUkOqiN7ZMFdn9jBkExpmHUMGBFknbOJtfxqt7Y%252BZHM0ilWgs1x8ITYOz8jxMBqnkuq499gTbuXOSCwIPkMZWNwFZM2KmrWgQ9fvnwbyNM1ks22ohROJ4X8CGSkUpnGQQ0J58CuRxeDCoDV6o%252BgFabKn7FGRa4Jy8PwVi03IlOTiDX2uw%253D%253D%7Ccksum%3A1137234806702c60152cb21440d89079953a91f6adf9%7Campid%3APL_CLK%7Cclp%3A2334524


or get my own block bored. Seems like the cost would be less for the used block but that one on eBay looks suspiciously clean in the cylinders. From all the listings I've seen on eBay, it looks like Mercury has used this same block on every 20-25hp built since the early 80's. The only difference seems to be on the other half where they changed the design slightly to accommodate a larger shifting rod.

 

[Scott Danforth]

I would get your block bored, buy new pistons and rods, new bearings, new reeds, and a new gasket set.

 

[flyingscott]

https://www.ebay.com/itm/WSM-Powerh...p-1994-2006-100-04-13-75mm-SIZE-/202581303798. This may not be the right size but they have more. Find a shop that can do a blind bore Mercosil block and away you go. Should be able to do that yourself for less than a $1000 US. And you will have pretty much a new motor. An older block will fit but stay with the one that has a thermostat. Also the blocks are not the same they are chrome lined blocks up until about 94 then went to Mercosil.