# Mercury 25 hp 2 stroke, reliable?



## Sam K (Apr 24, 2020)

So I’ve owned a few small 4 strokes now but never a 2 stroke, looking to get a Mercury or Yamaha 25 from the early to mid 2000’s for my currently underway home build. As most of you probably know, they don’t go cheap if they’re in good condition. I’ve heard the Yamahas are bulletproof and the mercs are faster but I havnt heard much about the merc reliability. Anyone who’s been running one of these for a while able to attest to their reliability? Also interested in their performance vs a modern 20 hp EFI like the Suzuki. I’m pretty handy so I can probably fix small things and am capable of cleaning carbs etc, but I don’t want to spend a ton of time working on it when I can buy an almost new 20 hp 4 stroke for maybe 400 bucks more. Also pointers on things to look out for when buying a used 2 stroke would be great. Any input welcome, thanks.


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## DuckNut (Apr 3, 2009)

If they sucked, do you think they would have sold millions of them?


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## ZaneD (Feb 28, 2017)

Without question I would go with a new 4 stroke instead of an older 2 stroke. The four strokes just can’t be beat when it comes to reliably, quiet, smooth, easy starting, no nonsense operation. An old two stroke is a tad lighter with a little more hole shot and speed, but to me I’d rather lose a couple MPH than sit at the ramp cranking my 15 year old engine that smokes and sputters.


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## jackson man (Aug 13, 2020)

DuckNut said:


> If they sucked, do you think they would have sold millions of them?


Oh, I don't know! How about the Ford Pinto? 😟


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## Sam K (Apr 24, 2020)

DuckNut said:


> If they sucked, do you think they would have sold millions of them?





ZaneD said:


> Without question I would go with a new 4 stroke instead of an older 2 stroke. The four strokes just can’t be beat when it comes to reliably, quiet, smooth, easy starting, no nonsense operation. An old two stroke is a tad lighter with a little more hole shot and speed, but to me I’d rather lose a couple MPH than sit at the ramp cranking my 15 year old engine that smokes and sputters.


Generally I agree with you. I’ve seen enough people struggling with their old motors at ramps to be wary. Any idea if a new 20 hp compares at all to a 25 2 stroke? The boat it’s going on will be 16’6” by 66 inch beam and about 250 to 300 lbs dry. Standard poling skiff hull shape. The increase in price and weight between 20 and 25 hp 4 stroke is so massive.


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## Sam K (Apr 24, 2020)

Sam K said:


> Generally I agree with you. I’ve seen enough people struggling with their old motors at ramps to be wary. Any idea if a new 20 hp compares at all to a 25 2 stroke? The boat it’s going on will be 16’6” by 66 inch beam and about 250 to 300 lbs dry. Standard poling skiff hull shape. The increase in price and weight between 20 and 25 hp 4 stroke is so massive.


Compares performance wise I mean. I’d like to get about 25 mph with me and a buddy and light gear.


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## DuckNut (Apr 3, 2009)

Sam K said:


> Compares performance wise I mean. I’d like to get about 25 mph with me and a buddy and light gear.


I can't say if you will reach those speeds - but...

I thought the 20 and 25 are basically the same motors and there is no weight difference (4 strokes). The weight different between 4 and 2 strokes is a bunch. The 2 stroke will have low end torque. The 4 will be smoother at high speed.

The reason people struggle with motors is because they have not maintained them not because the older smokers are any less reliable.

I think you just have to make up your mind if you want quiet or loud on the back of your boat and buy the appropriate motor.


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## DuckNut (Apr 3, 2009)

jackson man said:


> Oh, I don't know! How about the Ford Pinto? 😟


There's always one in the crowd! 

However, if you look back that Pinto was a very reliable car. Reliability did not come into play until struck in the rear.


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## bw510 (Sep 1, 2011)

Mines never let me down in 6 years 
The only reason I’d replace it is because I’m half def from how noisy it is


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## coconutgroves (Sep 23, 2013)

Merc 2 stroke 25 hp = 119 lbs
Yamaha 4 stroke 25 hp = 126 lbs pull start, 132 lbs electric and pull. It also has battery free EFI - you don't need a full size battery with cranking amps with the pull start. That saves more weight.

Go with the 4 stroke if you can, more efficient, warranty, and you have peace of mind of having a new engine. Yeah, you can work on those 2 strokes easily, but parts can add up. I put a new power head on my 90 Yammy 2 stroke, then had tilt and trim issues that resulted in pretty much replacing the entire T&T unit due to parts being worn and not being friendly for removal and re-install. Should have just got a new engine in hindsight.


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## TroutNreds12 (Jan 4, 2016)

Those small 4 strokes are dogs in my opinion.. I had a new 25 Yamaha 4stroke the light one it’s doesn’t even come close to the power of a Merc or Yamaha two stroke.. if you want quite smooth then get a 4 stroke but to me on small boats the old two stokes can’t be beat.. if u find a super clean one there super reliable simple nothing to go wrong computers n all the stuff on these 4 strokes today.. anything 30 and below I personally wouldn’t have a 4 stroke


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## jlindsley (Nov 24, 2015)

I have owned both but with go with a 4 stroke all day.
They are quiet, reliable, help with resale.

Another thing not mentioned above is the fuel economy is much better so your range increases significantly.

bugs are worse though in am when you first stop up a 4 stroke compared to a 2 stroke


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## flyclimber (May 22, 2016)

I get about 27-28 with almost full fuel and two people, 30 by myself with a 25 Merc. Like said above, no issues so far, I do have some quirks with my outboard. (Three pulls to get it to fire and I have to tweak the carb every once in a while, but I also have aftermarket reeds for a bit more pop) It's definitely louder than the 25 hp yamaha, however you can buy 2 mercs and run them for the cost of a new yamaha 4s. My plan was to run this motor till it dies then buy the 4s.


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## flyclimber (May 22, 2016)

jlindsley said:


> I have owned both but with go with a 4 stroke all day.
> They are quiet, reliable, help with resale.
> 
> Another thing not mentioned above is the fuel economy is much better so your range increases significantly.
> ...


Not sure but I know I am almost always wide open with mine. Fuel economy drastically improves with less throttle!


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## TroutNreds12 (Jan 4, 2016)

I also owned a 20 Suzuki 4 stroke. It’s decent if your by yourself super light load but if u have two guys heavier load it does have any low end to get the boat on plane.. if u tested those 20hp which I think are closer to 18hp compared to a 25 Merc or Yama 2 stroke I think u will be disappointed in power speed.. like others have said there quite and reliable but I e never had a prob with any Merc 25s I’ve had


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## TroutNreds12 (Jan 4, 2016)

Doesn’t have low end


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## Vertigo (Jun 3, 2012)

Newer 4-strokes are great until something goes wrong with fuel injectors or the ECU or some other electronic doo-dad that is un-fixable without a factory computer rig. Yes, it can be fixed under warranty, but that doesn't mean there's no hauling the boat to and from a shop and waiting a few weeks (or months) for the repair to be done. Mighty inconvenient when you want to go fishing. The thing about an older 2-stroke is that most things can be fixed by anyone with a little mechanical aptitude, no need to haul to a dealer, maybe you can even fix it yourself. Parts are relatively cheap.


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## coconutgroves (Sep 23, 2013)

@Sam K - your beam is 66", which gives you adequate displacement for a little heavier engine. A 20 hp may be under gunning the boat - 16'6" by 66". The new HB Glades Skiff is 17'8" by 58" and they put 30 hp 4 strokes on it.

You may want to consider the Tohatsu 30hp 4 stroke - 157 pounds for the 15" - gives you more power, although it is a bit more expensive than the Yamaha 25hp 4 stroke. It also has battery-free EFI like the Yammy. But if you want power T&T, that is going to add cost and weight.


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## jlindsley (Nov 24, 2015)

Sam K said:


> I’m pretty handy so I can probably fix small things and am capable of cleaning carbs etc, but I don’t want to spend a ton of time working on it when I can buy an almost new 20 hp 4 stroke for maybe 400 bucks more.


For $400 more you can have a 5-7 year warranty, brand new engine, noticeably better fuel economy
or you can save $400 and get the opposite of the above with a possibility of the engine being toast and needing a rebuild.

Look at it like cars. I love my 68' jeep and can work on it but I also love my "computer" toyota tundra. These new outboards are very reliable and normal maintenance items can still be done by yourself.


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## ek02 (May 8, 2012)

If you find a 2 stroke, check the compression for sure and pull the drain plug on the lower unit to see what the oil looks like and see if there are any big pieces of metal on the plug if it is magnetic. Oil should barely dribble out or not at all if the seals are good. A fresh water only motor would be a good thing too.


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## devrep (Feb 22, 2009)

the merc 25 2 stroke was known in the day to be closer to 30hp. it had no peer.


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## Viking1 (May 23, 2010)

I have owned a second hand 2001 Merc 25HP 2 stroke for 10 years. It is one of 3 other motors from 6 HP to 250HP. This motor has a cult following for a good reason. My 25 HP Merc has been bullet proof. All I have had to do is change out the water pump every 2 years and the lower unit oil once a year. This year I finally cleaned out the carb and picked up 3 MPH on the top end. This motor is easy to work on, so I have been able to do the work myself. I have the 25 HP Merc on a LT25 and I get about 10 MPG.

As far as the 2 vs. 4 stroke debate I plan to run the 2 stroke Merc for a long time. If I was going to get a new motor I would probably go the 4 stroke route to get better range. Four stroke technology has come a long way and is reliable. As far as hole shot goes 4 stroke performance is good enough for me and has not kept me from getter to where I need to go or out of a place when I need to go home. Bottom line between 2 or 4 stroke I don't think you can make a bad decision.

If you do buy a used 25 2 stroke Merc check engine compression, should be around 125 psi for each cylinder. Check the lower unit fluid, should be clean and not milky looking. Its best if you can take it for a run. Running the motor on the water at speed will tell you more about the motor than just running it on a hose in the driveway. For instance a stalling motor when giving it full throttle will tell you if you have a fuel issue like a clogged carb. Look at the prop and skeg for damage, that will give you an indication of how it was abused or used.


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## Sam K (Apr 24, 2020)

thanks everyone for your input. Leaning towards taking a gamble on a merc 25 because a new or newish 4 stroke over 20 hp is just out of my budget I think. Will bide my time a bit and wait for a nice one


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## Sam K (Apr 24, 2020)

Here’s the beast it’ll go on eventually. Just got her off the mold and ready to do the inside last weekend. Will post a bragging spot post when she’s done for any that are interested.


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## Backcountry 16 (Mar 15, 2016)

Got 2 my favorite motor super light way more torque than a 4 stroke less moving parts


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## Sam K (Apr 24, 2020)

Backcountry 16 said:


> Got 2 my favorite motor super light way more torque than a 4 stroke less moving parts
> View attachment 164343


What boat? Looks like it hauls ass with a 25


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## Backcountry 16 (Mar 15, 2016)

Sam K said:


> What boat? Looks like it hauls ass with a 25


East cape Gladesman yes around 31 or 32 solo.


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## Sam K (Apr 24, 2020)

Backcountry 16 said:


> East cape Gladesman yes around 31 or 32 solo.


Thought so, cool boats. Wish they made them still


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## Backcountry 16 (Mar 15, 2016)

Sam K said:


> Thought so, cool boats. Wish they made them still


He will still make you one if you contact him. I like the build you got going on.


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## Sam K (Apr 24, 2020)

Backcountry 16 said:


> He will still make you one if you contact him. I like the build you got going on.


Thanks. Only 100 hrs of work or so left


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## jlindsley (Nov 24, 2015)

You may have seen this already but below-








25 hp Mercury 2 stroke Tiller with 20” shaft, electric...


As the title states. 2003 Mercury 25 hp two stroke tiller motor with 20” shaft and electric start. This was on my son’s 16’ Smitty and used almost everyday / night When the weather allows. (Must be nice) In the last year the following has been done. Water Pump, Lower resealed. Thermostat...




www.microskiff.com


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## David Porter (Feb 2, 2020)

Sam K said:


> So I’ve owned a few small 4 strokes now but never a 2 stroke, looking to get a Mercury or Yamaha 25 from the early to mid 2000’s for my currently underway home build. As most of you probably know, they don’t go cheap if they’re in good condition. I’ve heard the Yamahas are bulletproof and the mercs are faster but I havnt heard much about the merc reliability. Anyone who’s been running one of these for a while able to attest to their reliability? Also interested in their performance vs a modern 20 hp EFI like the Suzuki. I’m pretty handy so I can probably fix small things and am capable of cleaning carbs etc, but I don’t want to spend a ton of time working on it when I can buy an almost new 20 hp 4 stroke for maybe 400 bucks more. Also pointers on things to look out for when buying a used 2 stroke would be great. Any input welcome, thanks.


I had a late 90’s 2 stroke Merc 25 and went through two power heads before I finally gave up and went to a Yamaha 4 stroke. I love the shifter in the throttle handle but they just have issues with the top end.


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## TGlidden (May 24, 2013)

Both the Yamaha and Mercury 25 2 strokes are great motors. The Yamaha is bomb proof if properly maintained, but a true 25hp. The Merc is much less reliable, but a 30hp. The F25 Yamaha is a solid motor that’s close to the Merc 2 stroke in top end, and powers a 16’ Waterman ( Whip and El Dora) hull well. Pretty similar size to your build.


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