Mercury 15hp vrs 20hp outboard

I'm in a similar situation in thinking about getting a larger outboard. It seems like these engines are all receiving favorable remarks. Are there any 15-20 hp outboards that people really don't like?
 
We have the Highfield 310 and have been using a Mercury 15hp 2 stroke tiller style the last couple years, lots of power and popped the three of us out on plane right away, I just upgraded it this year and added the steering wheel console and a 20hp Suzuki EFI motor to our 310. While I absolutely love driving the dinghy with throttle and steering wheel, the 20hp is quieter and no smoke but it does take longer to get up on plane.
 
I did end up upgrading to a 15 HP Mercury 4 stroke this year. Its heavier and physically larger than the 15 Evinrude it replaced, but so far is doing nicely. Performance is about the same as the Evinrude, with the benefit of being MUCH more quite and using less fuel. The kids can really sneak up on us now. I would likely benefit from some smart tabs due to the heavier transom weight.

I did consider buying the 20 HP engine because as folks have noticed the 15 is the same as the 20, but detuned. Anyone considering uprating the engine should know that the manual states if you replace certain parts to convert to a 20 HP, the ECU will detect it and shut down.
 
How are people dealing with the outboards when not in use? Is everyone keeping the motor on the dink and on davits?
 
To close this out for now :)… I have been going back and forth and wasting my summer away so I decided not to try and put a big dinghy on this boat with manual davits. I will wait until I have a hydraulic swim platform.

So I bought a small Zodiac Aero 270 ...I have had good luck with them, 5 year warranty and cheap enough. Its the right size to pull up on the swim platform without davits and tie down with little effort.

View attachment 85904

I have always had a Tohatsu 4hp....that I converted to a 6hp. Its been sitting for a couple years so changed the oil, new fuel filter, fuel pump, spark plug, new coil and took the carb apart and cleaned it..... runs like new now

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Then I bought a bad ass prop for it....1" in diameter bigger and 1" more of pitch... I am leaving the 4hp sticker on it so its a true sleeper :)

View attachment 85905

Should be good to go now to putt around the marina... and win some races :)
I’m in the market for the same highfield with a 15 or 20horse. I’m told they’re all on backorder right now.
 
I’m in the market for the same highfield with a 15 or 20horse. I’m told they’re all on backorder right now.
The zodiac I wanted was back ordered until October ..... they sold me a bigger last year model for same price
 
How are people dealing with the outboards when not in use? Is everyone keeping the motor on the dink and on davits?

Currently I keep it on the dink and tied to the dock. Previously I kept it on a St Croix motor mount attached to the swim platform. The dink used to be on tip up Weaver davits.
 
Save yourself heartache and money and go with the most hp you can. You will end up in the end with that engine anyway. I have been through several and I now currently run a yamaha 25hp on a AB 9VL. Its rated at 15hp but is best with the 25hp. Place I bought it said no way they would do that for me. I did it myself. Lol liability reasons. Later after I did it they told me a lot if their customers do the same thing. It is the most fun dinghy I have ever been in. Runs 33mph with just me and i can run mid 20s with 4 adults easily. And before anyone says I'm crazy the 9vl and 10vl AB has the same transom design. I looked at both very carefully and compared the two. Only difference is one foot of length. 9 is rated at 15 and the 10 is rated at 25. I run the boat like crazy and it will not break it. Trust me. :D
 
Save yourself heartache and money and go with the most hp you can. You will end up in the end with that engine anyway. I have been through several and I now currently run a yamaha 25hp on a AB 9VL. Its rated at 15hp but is best with the 25hp. Place I bought it said no way they would do that for me. I did it myself. Lol liability reasons. Later after I did it they told me a lot if their customers do the same thing. It is the most fun dinghy I have ever been in. Runs 33mph with just me and i can run mid 20s with 4 adults easily. And before anyone says I'm crazy the 9vl and 10vl AB has the same transom design. I looked at both very carefully and compared the two. Only difference is one foot of length. 9 is rated at 15 and the 10 is rated at 25. I run the boat like crazy and it will not break it. Trust me. :D

Holy moly. I have a 9VL and the 15 HP does pretty well. I've gotten to 25 MPH easily and it feels like a rocket. I can't imaging getting that dinghy to 33 mph.
 
I moved to a 15hp from my 6. With the 6 I was able to simply lift it off the transom of the dink, lay on the swim platform and store in the cockpit when not in use.... now, with the 15, I think the additional 40 or so pounds may prevent that from happening. I find getting the dink onto the platform easy enough - but I'm at the crossroads of spending $5K on a davit like the H3O on a boat that I'll only have for probably another year or so... any suggestions?
 
I believe the Merc engines are identical to / made by Tohatsu in that HP range. The Tohatsu can indeed be upgraded by replacing the ECU. That said, it's cheaper up front to get the the 20 HP, as the ECU runs around $900.
 
I love it when you come home after a weekend at the boat and you have boat presents waiting in the garage.... new motor for the dinghy. :)

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Where did you buy it from? I'm looking at outboards for our dink. What horsepower and shaft lenght did you get? <insert jokes here>
 
I bought a zodiac 310 aero... it’s rated for a max 9.9 hp So that’s what I bought.... short shaft...it’s not how long you are.... it’s how fast you can go :)

I usually buy from onlineoutboards.com but they were out of stock 2 weeks ago.....so I bought from powerequipmentdirect.com.... they were okay to deal with but a bit slow ...but okay
 
I got mine from Defender during their spring sale. I picked it up, but they have been good to deal with. It came with an extended warranty to boot.

Unfortunately I've had to use the warranty already. At about 20 hours the shift shaft sheared off inside the lower unit. There is a hole in the shaft for a connecting pin; the shaft snapped at that hole and the motor was stuck in reverse.
 
Holy moly. I have a 9VL and the 15 HP does pretty well. I've gotten to 25 MPH easily and it feels like a rocket. I can't imaging getting that dinghy to 33 mph.
I heard it walks at that speed!
 
I heard it walks at that speed!
The RIB does ride quite differently with the new Mercury vs. the old Evinrude. The boat is quieter and actually does get on plane faster. But I do have to shift my weight forward a bit to prevent porpoising. Also the ride is a bit squirrely at the top end.

Frankly, the motor is a bit weird. Where the Evinrude had a very rigid connection, the Mercury seems to have some sort of elastomer in the area between the mount and where it attaches to the actual motor. Maybe this is designed to make the ride softer? The practical effect is that it makes the motor oscillate at higher speeds and wiggles the bow of the boat.
 

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