Late model Merc 20 & 25 horse engines

[ehenry]

Was just looking on Merc's website and compared the spec's on their 20 & 25 horse engines. The only thing I saw that was different was the max rpm @ WOT which was only 500 rpm. If thats the only difference why even offer the two engines since there isn't that much of a difference anyway? I'm sure it wouldn't be that hard to get 500 more rpm's out of the 20 horse and save yourself a few hundred bucks. Anyone got any wisdom on this? Just curious really.

 

[Waco]

Re: Late model Merc 20 & 25 horse engines

Hey I heard the same thing. I sure would be interested to know the skinny on this one, as my boats Max. Hp rating is 20. Seems like you could shorten the pitch alittle, get more rpms = more HP.

 

[skier]

Re: Late model Merc 20 & 25 horse engines

Hello Guys:<br /><br />I really hate to burst your bubble but, the difference isn't the RPM's, it's the exhaust port size.

 

[Waco]

Re: Late model Merc 20 & 25 horse engines

i knew there was a catch somewhere in there.

 

[ehenry]

Re: Late model Merc 20 & 25 horse engines

No bubble to bust. I was just looking at what Mercury listed on their web page for the two different engines. The only difference on the spec sheets listed is WOT rmp. Like WACO, I knew something else had to be different. Was just curious as to what else was different.

 

[trevorcday]

Re: Late model Merc 20 & 25 horse engines

The 25HP uses a bigger carb venturi too.

 

[DJ]

Re: Late model Merc 20 & 25 horse engines

Horsepower differences USUALLY include some internal "tweaking". The larger ports, jets, etc. ALLOW it to turn faster.<br /><br />Turning it up higher with a different prop would not gain anything. The reason being is that it is already at the peak of its horsepower curve on the fuel map. Actually, you could even lose horsepower.