repower ??????

Joined
May 23, 2008
Messages
29
I am running a 20' twin vee that is rated from 90hp-140hp, I have a 1999 johnson 90hp 60degree looper on it now. The ? is I am thinking of switching to a 3 cylinder 90hp motor (yamaha or tohatsu) will i notice any loss of power with the loss of the 4th cylinder ?
 

TOHATSU GURU

Admiral
Joined
Jul 22, 2004
Messages
6,164
Re: repower ??????

Probably no loss at all. If any, it will be so slight as to be forgotten when you see how much less fuel and oil you use.
 

trendsetter240

Lieutenant
Joined
Jun 22, 2009
Messages
1,458
Re: repower ??????

No HP loss if both are rated to produce 90HP at the prop shaft. You may see a different torque profile though. I'd expect the v4 would have more low end torque than the inline 3.


Agreed that you will see a fuel improvement. If you go with a new tohatsu that is DFI you will see an even larger fuel efficiency improvement.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: repower ??????

Yes, you will see a difference. The 3 cylinder 90 will not have the torque the 60* V4 has. The IL 3s won't rev as quick as the 60* V4. Night & day difference.
 

TOHATSU GURU

Admiral
Joined
Jul 22, 2004
Messages
6,164
Re: repower ??????

Not as much of a difference as you might think. Most of our sales are as re powers rather than as purchased with the boat and most people who haven gotten rid of those old J & E's say that Jap 3 cyls get up just as quick as before. Occasionally someone will say it doesn't seem as quick to them out of the hole and chances are they are right, but all agree that any difference is so slight as to not be major point with them. I do agree that if everything else was the same, the 4 would have more hole shot. The thing is, everything else isn't the same. Tech and tuning have come a long way towards compensating for traditional givens such as number of cylinders and raw cubes. The Etec 2-cyl 25 is a prime example that number of cylinders doesn't mean that an engine is a dog. The Etec 2-cyl 40 is a dog. It's all about the way the things are designed.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: repower ??????

Could be but we've not seen that. Maybe compared to an old crossflow V4 but never yet seen any 3 cylinder that will even come close to the torque of the 60* V4.
 
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