15hp vs 20hp 4stroke suzuki efi difference

boater1234

Master Chief Petty Officer
Joined
Jan 6, 2010
Messages
869
Well i have been trying for a long time to find out what the difference is between a 15 and 20hp 4stroke outboard in general.Well i got my answer from youtube.I watched a guy from suzuki marine do tests on the same boat(inflatable) with 2,3, and 4 people with the 15hp first then the 20hp.

The difference was huge in the take off power and top end.The 15hp was able to get 2 people on plane with ease but when it came to 3 it struggled,with 4 it just took forever to get them on plane,close to 20 to 25 seconds.The top end was decent with 2,3 and 4 people with the 15hp but like i said once 3 and 4 people were on the boat it struggled a ton to get them on plane,once on plane they all had good top end speeds.

The 20hp had no problem getting 2,3,or 4 people on plane,plus the top end was awesome for all 3 tests to.The guys were probally 150 to 180lbs per person so thats not to bad for a 20hp,thats say 100lbs for the motor and close to 600-700lbs of people.

I'm def convinced to get the 20hp suzuki,it has def showed me from tons of videos how powerful of a little motor it is.It has very smooth acceleration and tons of power,also very quiet at idle.

Well i just figured i would post this if anyone was interested in the difference between the 2 and contemplating which one to get.The 20hp is worth every extra penny over the 15hp.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Re: 15hp vs 20hp 4stroke suzuki efi difference

The 20hp is worth every extra penny over the 15hp.

It's worth all the extra $$$$ only if you are planing to take more than 4 boaters in each outing, if just outing with 2-3, 15 HP will suffice. Will depend also on the hull type, sib-rib proper inflation, perfect ballance, trim, engine height, water conditions as to plane faster. Anyway + 5 HP is 25% more punch over a 15.

Happy Boating
 

1datsroj

Cadet
Joined
Jun 27, 2011
Messages
14
Re: 15hp vs 20hp 4stroke suzuki efi difference

I haven't seen the youtube video yet but I was wondering the same thing. Displacement, bore and stroke, gear ratio are all the same, looking at the specs every thing is the same, even the weight.
Except two things:
full throttle RPM range goes from 5000-6000 on the 15 to 5300-6300 on the 20
and the Prop goes from 9.25 x 9 to 9.25 x 10
 

boater1234

Master Chief Petty Officer
Joined
Jan 6, 2010
Messages
869
Re: 15hp vs 20hp 4stroke suzuki efi difference

It's night and day with the 15hp and 20hp,the proof is in the videos on youtube,you have to go through a ton of videos to find it but the guys name is VILEN SHUSHENACHEV and he shows tests with the 15hp 4stroke and the 20hp 4stroke suzuki on like 3 dif size inflatables.Like i said 2 guys with each motor works great,as soon as you get to 3 the 15hp labors bad,with 4 forget about it,it takes forever for it to get on plane of course it's an inflatable,a flat bottom jon would prob plane easier but hands down the power difference between the 2 motors is huge.The 20hp had no problem getting 3 or 4 men on plane as with the 15hp it did.To me spending like $200-$300 more is well worth the extra power and quickness to plane,but thats just my opinion.

UPDATE:Ok what you need to do is punch in 20hp 4stroke suzuki on youtube then on the top of it all it will have a video that says suzuki df20a break in by robert heilman,hit that and it will take you to all this guys videos(VILEN SHUSHENACHEV) on the right hand side.That is where i saw all the videos.Let me know what you think after watching them all.There is a bunch of them.
 

1datsroj

Cadet
Joined
Jun 27, 2011
Messages
14
Re: 15hp vs 20hp 4stroke suzuki efi difference

I watched the inflatables videos, wish it was English, too bad they weren't tested on the exact boat to compare apples to apples. Anyway the post earlier was based on the specs from each motor on Suzuki's website.

I was able to dig a little bit deeper to find the exact differences between the two from the Suzuki Parts catalog DF15A/20A.

The 15 has a restrictor plate in the inlet manifold where the 20 has silencer seal and a flame arrestor. pages 15 and 16 of 66. This would be relatively cheap and easy to change.

The kicker is the engine control unit on the ignition coil pages 32 and 33 of 66. part # 33920-89L00 for the 15hp and #33920-89L20 for the 20hp. unless one could reprogram the chip the part is over $600.

There are some nice sales on them that end very soon, too bad the gimme six promotion starts on the 40HP and up

source

http://www.suzuki.com.mx/Marinos/img/Catalogos/DF15A _20A_9900B-45247.pdf

not sure if one can post links in here, I've seen forums before where there frowned upon but I figured a parts catalog cant hurt much, please forgive if I have done wrong :)
 

boater1234

Master Chief Petty Officer
Joined
Jan 6, 2010
Messages
869
Re: 15hp vs 20hp 4stroke suzuki efi difference

There is tests with the same boat,you just have to search through them all,it's a pain in the butt.There is tests with the 15 and 20hp on a 360 inflatable boat,same exact boat with the 2 dif engines.Then they test the 380 inflatable,then the 420 inflatable.
 

1datsroj

Cadet
Joined
Jun 27, 2011
Messages
14
Re: 15hp vs 20hp 4stroke suzuki efi difference

one could drill out the restrictor plate so it would be like the silencer seal, the flame arrestor is $9.00. Any one know about reprogramming ecm?
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Re: 15hp vs 20hp 4stroke suzuki efi difference

Will need a buddy at the factory to provide such info about reprogramming ecm parameters, that should be near top secret, if not, everyone would be upgrating their 15 horses to 20 for penauts cost. Anyway, will need to start by swaping 15 to 20 prop model.

Happy Boating
 
Top