2 stroke verses 4 stroke ?????

Reply

  #1  
Old 07-27-10, 07:43 AM
Member
Thread Starter
Join Date: Aug 2006
Location: USA
Posts: 18
2 stroke verses 4 stroke ?????

I had a mercury dealer tell me that a 2 stroke 90 HP is more powerful than a 90 HP 4 stroke. Is that true?
 
Sponsored Links
  #2  
Old 07-27-10, 12:53 PM
Forum Topic Moderator
Join Date: Oct 2002
Location: Hamilton County, Ohio
Posts: 4,288
Ninety horsepower is ninety horsepower if rated by the same scale. However, the 4 cycle may have a better torque to horsepower ratio.
 
  #3  
Old 07-27-10, 01:11 PM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 18,651
Typically, the same size engine will have more hp in 2 stroke, but 90 hp is 90 hp

Will they tell you the torque figures? I knew a car salesman who summed it up, "horsepower ratings get people into the showroom but when they drive it, it's the torque which makes the sale."
 
  #4  
Old 07-27-10, 01:58 PM
Member
Thread Starter
Join Date: Aug 2006
Location: USA
Posts: 18
Thanks for the info.

I will ask what torque is?

Blair
 
  #5  
Old 07-28-10, 03:50 AM
Member
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
To say that one 90 HP motor has more torque than another 90 HP motor is somewhat misleading without knowing the RPM ranges over which the motors develop their horsepower.

Generally 4-stroke motors develop their rated horsepower at lower RPMs than their 2-stroke counterparts.

Another difference between 2-stroke and 4-stroke: Environmental. 4-strokes don't burn a mixture of gas & oil and tend to burn cleaner.
 
  #6  
Old 07-28-10, 01:05 PM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 9,721
I agree that these HP ratings are quite misleading.

I just bought a new Mercury 3.5 hp 4 stroke for my canoe.
Had a choice of a 3.5 or a 2.5 hp, the 3.5 being $100.00 more.

I already knew exactly what the difference between the two was but asked the salesman anyway.
He said they put a bigger carb and tuned the 3.5 higher.
1 hp is not a lot of hp but it is a 40% increase over the 2.5.

In reality the engines use the same carb and have the same bore and stroke.
The reason one has a higher hp is that the 2.5 is rated at 5500 rpm and the 3.5 at 6000 rpm!
Pretty clever marketing I think!
What is even more clever is that all Merc engines under 25 hp are made by Tohatsu whose engines are less expensive.
 
  #7  
Old 07-29-10, 02:45 AM
Member
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
20 years ago we figured the difference between my Merc 170 and my friend's Merc 190: 2bbl carb vs 4bbl carb and his also had heavier lifter springs. Both were 4-bangers.

I could understand the carb, but springs?
 
Reply

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


Thread Tools
Search this Thread
Display Modes