Reply
 
Thread Tools Search this Thread Display Modes
 
Old 05-31-2018, 02:26 PM   #21
Guru
 
tiltrider1's Avatar
 
City: Seattle
Country: USA
Vessel Name: AZZURRA
Vessel Model: Ocean Alexander 54
Join Date: Aug 2017
Posts: 2,021
Didn't mean for my last post to sound so harsh. Was not directed at anyone or ment to insult any one.
__________________
Advertisement

tiltrider1 is offline   Reply With Quote
Old 05-31-2018, 02:49 PM   #22
Guru
 
City: Northport
Country: USA
Join Date: Aug 2015
Posts: 1,648
Quote:
Originally Posted by Shrew View Post
I raced with a buddy in identical ribs. The dinghy I was in had an 8HP 2 stroke Johnson (it might have even been a 7hp). My buddy had a 9.9 Merc 4 stroke.

Off the line the 2 stroke was on plane and clearly had the hole-shot. I was able to very quickly pull away. Within minutes I had the 4 stroke merc by a HUGE lead (50+ boat lengths). So much so, I dind't bother looking back again. The race was about 1-1.5 miles (We were travelling from point A to Point B and decided to race for fun). About half-way there, the 4stroke merc passed me. I eventually lost sight of him.

The two-stroke definitely had the hole-shot and over short distances was a sprinter. The top end on the 4stroke was much higher and over time and distance crushed the 2 stroke.

I do think there are variables at play. However, not enough to change such a lopsided outcome.
"I do think there are variables at play. However, not enough to change such a lopsided outcome"

Prop pitch , prop type, prop condition, trim angle, mounting height of outboard.
Any one of the above can easily change the performance of the same engine no matter what type it is.
With a couple of these in play you can get a 20% difference in top speed with the same engine.
I know only because we have baselined these on a few RIBS and then varied the items to get a best fit for the use.
Most folks do not even pay attention to some of these but they all make a large difference.
__________________

smitty477 is offline   Reply With Quote
Old 05-31-2018, 02:55 PM   #23
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 9,070
With a 20 or 25 hp engine on 10’4” rib, you’ll be able to water ski behind it.
Larry M is online now   Reply With Quote
Old 05-31-2018, 03:13 PM   #24
Guru
 
City: Northport
Country: USA
Join Date: Aug 2015
Posts: 1,648
Quote:
Originally Posted by Larry M View Post
With a 20 or 25 hp engine on 10’4” rib, you’ll be able to water ski behind it.
Not quite - but with a 12.5 RIB with a 40 hp it starts to become possible.
smitty477 is offline   Reply With Quote
Old 05-31-2018, 04:40 PM   #25
TF Site Team
 
Baker's Avatar
 
City: League City, Tx
Country: Texas
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
Posts: 6,857
Quote:
Originally Posted by Ski in NC View Post
I'd shop for a 15 Yami two stroke. Little critter with way plenty power for a dink. Over that in hp and it's overkill.
I am the proud owner of a 2010 model of one of those....the last year they were sold here.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
Baker is offline   Reply With Quote
Old 05-31-2018, 04:47 PM   #26
Veteran Member
 
helm's Avatar
 
City: Isleton
Country: USA
Vessel Name: Maverick
Vessel Model: Lindell 36
Join Date: Apr 2015
Posts: 90
You might look at the Suzuki 20, we have one on our Caribe MVP 10. It has really been a great motor
helm is offline   Reply With Quote
Old 05-31-2018, 05:10 PM   #27
Guru
 
High Wire's Avatar
 
City: Cape May, NJ and Englewood, FL
Country: USA
Vessel Name: Irish Lady
Join Date: Dec 2007
Posts: 3,407
The Yamaha owner manual for a 25 2-stroke 15” shaft rope start says 106#.
60# two stroke?? Maybe an 8 hp from long ago.
__________________
Archie
Irish Lady
1984 Monk 36 Hull #46
Currently in New Jersey.
High Wire is offline   Reply With Quote
Old 05-31-2018, 05:18 PM   #28
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 17,037
Like Smitty says ... many other factors. Variables.

I don’t know why 2s smoking would even be mentioned. I run 40-1 dino 2s oil and only at startup do they smoke. Like an FL .. actually much less and lighter color.

But the mixing is something else to do kinda like ya take off your pants to have sex and I’ve never heard anyone complaining about that.

Where to store the gas is a problem but 2s/4s don’t matter.

Archie,
I think my 6hp Johnson and 8hp Yamaha are both very close to 60lbs.
__________________
Eric

North Western Washington State USA
Nomad Willy is online now   Reply With Quote
Old 05-31-2018, 05:20 PM   #29
Guru
 
City: Northport
Country: USA
Join Date: Aug 2015
Posts: 1,648
Quote:
Originally Posted by High Wire View Post
The Yamaha owner manual for a 25 2-stroke 15” shaft rope start says 106#.
60# two stroke?? Maybe an 8 hp from long ago.
Exactly - here is the manual , page 42 has the specs.

https://www.yamahapubs.com/outboard_...8626-06-93.pdf
smitty477 is offline   Reply With Quote
Old 05-31-2018, 06:00 PM   #30
Guru
 
City: Boston
Country: US
Vessel Name: Adelante
Vessel Model: IG 30
Join Date: Nov 2016
Posts: 941
I would never exceed rated hp for RIB. (20hp)
I would choose quiet reliable easy to maintain 4 stroke.
I would opt for new engine with warranty over used engine if budget allowed.
I would consider used 7 or 8 year old 4 stroke priced in the $1000 range if budget didn't allow new
SoWhat is online now   Reply With Quote
Old 05-31-2018, 06:57 PM   #31
Guru
 
High Wire's Avatar
 
City: Cape May, NJ and Englewood, FL
Country: USA
Vessel Name: Irish Lady
Join Date: Dec 2007
Posts: 3,407
Quote:
Originally Posted by Nomad Willy View Post

Archie,
I think my 6hp Johnson and 8hp Yamaha are both very close to 60lbs.
Agree.
To the OP
My vote would be a new four stroke. My size limit based on what I could carry, and what my wife could pull start.
Other food for thought. A 25 hp 2 stroke will go through a 6 gal tank PDQ. Who needs the hassle of lugging fuel tanks around and mixing oil?
High Wire is offline   Reply With Quote
Old 05-31-2018, 09:10 PM   #32
Hospitality Officer
 
Andy G's Avatar
 
City: Pittwater
Country: Australia
Vessel Name: Sarawana
Vessel Model: IG 36 Quad Cabin
Join Date: Sep 2010
Posts: 1,786
FWIW, I have just gone through this. We needed to repower our 10' RIB. We had a 15 hp Yamaha. which worked very well on the boat but eventually developed some pretty terminal issues. So the hunt was on for a new engine.

I liked the simplicity of two strokes and as weight was a big factor, I steered away from four strokes. I finally settled on a 15HP US Mercury model over another Yamme, mainly because it was a little lighter and also it has the gear change on the tiller handle. This is a really handy thing to have. Also I have found the Merc is better just running around on idle than the Yamme was.
Andy G is offline   Reply With Quote
Old 06-08-2018, 01:07 PM   #33
Member
 
City: Minnesota
Country: USA
Join Date: Oct 2017
Posts: 18
LOVE my 2008 Yam 25 2.strk !!
Seems like good price on yours, but not up on pricing. My Yammer has been trble.free, burn only non-oxy 91, NEVER cheap out and buy the low.grade ethanol crap! With the money you save you can put on a SS prop, $250. Like mine alot.
Go for the Yamaha !!
WhitePelican is offline   Reply With Quote
Old 06-08-2018, 01:12 PM   #34
Newbie
 
Join Date: Jul 2009
Posts: 2
I have a 2005 25 hp Yamaha 2 stroke and a 2017 efi 20 hp Suzuki.

The Yamaha has way more power, Can get on plane with extra people on board, pull a knee boarder, etc.. can lay down and be stored in any position. Needs spark plugs and carb cleaned every year.


The Suzuki has less power, need to store certain ways or sides, less maintenance, clean, idles way better.

If you need power to carry extra weight or pull water sports, then get the Yamaha, other wise the 4 stroke is easier, cleaner.

Good Luck!!
GEOO is offline   Reply With Quote
Old 06-08-2018, 01:19 PM   #35
Member
 
City: Minnesota
Country: USA
Join Date: Oct 2017
Posts: 18
Re: 25 Yam, was also able to get our West Marine Rib5 on plane w 4 people, no prob; just as a test.
Our dinghy works best as a 2.seater, too crowded w 4
WhitePelican is offline   Reply With Quote
Old 06-08-2018, 01:30 PM   #36
Member
 
dotgone's Avatar
 
City: vashon, wa
Country: United States
Vessel Name: High Flight
Vessel Model: Symbol 557
Join Date: Aug 2015
Posts: 22
Cool yamaha 2 stroke

I am 99% sure you have the weights reversed. In any case I like the yamaha and you should be able to negotiate a little better price, say 1800 max.
Good luck on the loop.
dotgone is offline   Reply With Quote
Old 06-08-2018, 01:36 PM   #37
Newbie
 
Join Date: Jul 2009
Posts: 2
Weights are correct. 15 and 20 hp 4 strokes are light, (its a 15 hp tuned up) when you jump to 25hp, 4 strokes are heavier.
GEOO is offline   Reply With Quote
Old 06-08-2018, 03:06 PM   #38
Guru
 
City: Fairport, NY and Palm Coast, FL
Country: United States
Join Date: Jan 2017
Posts: 1,876
Quote:
Originally Posted by rjwilliams11741 View Post
I was having a hard time with the fact that you show Yamaha as being heavier than the Tohatsu and looked it up - the specs show the Tohatsu at 115 lbs for the short shaft and the 25 Yamaha short shaft at 60 lbs. If weight is an issue you might want to check those specs out again.
no way a yammi 25 is 60 lbs. The best in class Mer 15 2 st is 74 lbs.
diver dave is offline   Reply With Quote
Old 06-08-2018, 03:21 PM   #39
Senior Member
 
City: PNW
Country: USA
Vessel Model: American Tug 435
Join Date: Jul 2014
Posts: 258
Looks like you'll get opinions both ways so I'll throw one in. I'd definitely go 4-stroke because i'd never want the extra noise, smoke (even if it is just at startup), and oil mix hassle of a 2-stroke.
i have a 4-stroke 15hp on about the same size RIB and as others have said, 20hp is likely more than you need. Our 15 hp goes almost uncomfortably fast as is.... If i had to buy another motor I'd probably drop down to the 10 hp range or start thinking about a Torqueedo....
Hamrow is offline   Reply With Quote
Old 06-08-2018, 06:27 PM   #40
Member
 
City: SWFL
Country: USA
Vessel Name: Great Commission
Vessel Model: 1988 Grand Banks 32 #793
Join Date: Nov 2017
Posts: 11
Well I went with the 2 stroke 25HP Yamaha for $1850. My reasoning....... I can fix it if it breaks. usually just a dirty carb or needs spark plugs. The 4 stroke is more complicated design the may require special knowledge and computers to repair and diagnose. I Like simple. Also considering cost of ownership after a few years the Yamaha will depreciate much less and perhaps go up in value where as the new Tohatsu will most probably go down on value.
__________________

Reel Grace is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 07:48 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×