# 20HP vs 25 HP Four Stroke



## BLKLAB (Aug 13, 2012)

Does the additional 5 HP offset the weight difference?


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## Johny25 (Aug 14, 2012)

Well what brand 4 stroke motor are we talking about? And usually the difference between a 20 and 25 is about 500 RPM on the top end. Holeshot usually doesn't change much but top end you will get a few more mph. Typically the 20 and 25 have the same block just different carb, intake or exhaust tubes. But with all the computer crap nowadays it could be just a computer chip lol


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## BLKLAB (Aug 14, 2012)

Well let's say a Mercury for example. They offer a 20 HP and a 25 HP. The 20 is a 2 cylinder vs the 3 cylinder 25. The 20 is 5250-6250 RPM and the 25 is 5000-6000 RPM. They have the same fuel induction and ignition systems. The 20 HP has a carb, the 25 HP is EFI. The 20 HP weighs in at 115 lbs. The 25 is at 157 lbs. So back to my original question, Is 5 extra HP worth the additional 42 lbs? Or would the 42lb weight savings make up for less power?


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## Johny25 (Aug 14, 2012)

Are you going to be taking the motor on and off a lot? And what kind of boat are you putting this on? 

If you have a light tin that is 14' or less the 20hp would probably be a better option as long as your not looking for lots of speed because the 25hp has a better gearcase for speed at 1.92:1 compared to the 2.15:1 of the 20. Also the 25hp LIGHTEST model is 157lbs so if you are wanting electric start, long shaft, power trim and tilt then you are going to be closer to 200lbs is my guess. 

If you have a 16' or bigger, you are not going to be taking it on and off, and you want top speed I would go with the 30hp instead of the 25. You would gain 10hp for 57 extra pounds versus 5hp for 42 extra pounds.

All this depends on what boat you have, how you use it and what you want to get out of it.


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## Ictalurus (Aug 14, 2012)

Johny25 said:


> Typically the 20 and 25 have the same block just different carb, intake or exhaust tubes. But with all the computer crap nowadays it could be just a computer chip lol



I've seen the new split in blocks among the four strokes between the 20 & 25. I think the 20 yammi checks in around 120 lbs and the 125 at 170 or so lbs. The 15 and 20 seem to now be the same platform. I would think you'd see some difference in performance even w/ the added weight, but I'm no engine guy and would recommend following j25's advice.


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## Ictalurus (Aug 14, 2012)

BLKLAB said:


> So back to my original question, Is 5 extra HP worth the additional 42 lbs? Or would the 42lb weight savings make up for less power?



I would say yes, but as johnny mentioned it would depend on boat. You get a few people in the boat and I'd bet you see less performance drop off w/ the higher HP. If you fish by yourself most of the time the 20 HP would probably move you right along.


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## lovedr79 (Aug 15, 2012)

25. its fuel injected. Nough said


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## sixgun86 (Aug 15, 2012)

lovedr79 said:


> 25. its fuel injected. Nough said




x2. 

Also need to consider the additional displacement = more torque. If the 20 is a 2cyl and the 25 is a 3cyl I'd say it easily makes up for the difference allowing you to go with a higher pitch prop. If your boat is a feather light though all that torque will go unneeded and weight could become more of a factor.


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## HBT Chris (Aug 15, 2012)

I don't know much about either of these engines, but I will say that going from a carb to fuel injection will spoil you. It's great to have a motor that just starts 8)


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## Ictalurus (Aug 15, 2012)

HBT Chris said:


> but I will say that going from a carb to fuel injection will spoil you.



Until the point it needs maintenance. I'm definitely not a motor guy, but I've rebuilt a carb before, not sure where to start on FI.


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## basstender10.6 (Aug 16, 2012)

Nowadays many companies put the same block in the 15hp and 20hp motors and different one in the 25hp and 30hp motors. So, essentially if you buy the 20, you are just buying a supped up 15, but if you buy the 25hp you are buying a de- tuned 30....


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## turbotodd (Aug 17, 2012)

EFI is awesome.

Carbs aren't bad either.

With either one, let the fuel get old and it WILL have problems. EFI is under a lot more pressure and will usually run on old fuel. For a while. Until the injectors become plugged.

I know nothing of any outboards other than the Yamaha's. The F15 and F20 are the same exact outboard. Carb is different. And so is the price. 

The F250, however, is way different. Bigger engine, bigger carb, bigger leg, etc. I've run a 1548 War Eagle with both an F20 and a F25. The difference is huge. The F20 was slow to plane and ran 19-20 mph. Bare boat with just me in it. The F25 jumped right up, ran smoother at top speed and maxed out at 28 mph. It would run 26 with 2 people and a big ol dumb black lab. The F25 is around 170 lbs. Heavy it is. It needs power tilt and it can be had for a little extra cash. The F20 is light (around 125 lbs, IIRC) and easy to tilt. Just not nearly as powerful as the F25 is.

SO in the case of Yamaha's small motors, I would definitely say the 5 HP difference certainly is worth the extra weight. The new F25's have tilt assist which is nice once you get used to it. You can tilt it with one finger. I've run some F40 tillers with tilt assist and it's pretty cool. Almost better than power tilt; IMO, but power tilt is usesless to me without trim.


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