mercury 2.4 vs. 2.5

[HYDROVAGAS86]

i would like to know if there is a significant diffrence between a mercury 2.4 200hp and a 2.5 200hp. both motors are carb motors and have cut heads too 140lbs. and fiber glass reeds. i figure that the 2.5 will have alittle more lowend grunt. but will the 2.5 spin a higher rpm , accelerate faster or is there no differance at all. i just want to know if it is worth getting rid of my 2.4 200 for a 2.5 200. sorry forgot to mention one of these motors will end up on the back of a 20' eliminator , if that makes a diffrence or not . if anyone has an opinion i would love to here it.

[Terry Jackson]

In mercury school, we were informed the mid 80's 2.4 200 had 219 hp, the late 80's had 212hp, and the 2.5 200 had 202hp. Personal experience tends to back that up, but the 2.5 has a better holeshot, the 2.4 may have an extra 1 or 2 mph on top. But this is only a dead stock comparison. I don't know how much any mod affect each, but unless you get a great deal, I would not change, unless you were going to modify. Also the boat you have may influence the outcome. (An Allison may be faster with the 2.4 while a F&S my be faster with the 2.5). The 2.5 weight 30 to 40 lbs more. The 2.5 has greater potential.

[HYDROVAGAS86]

thanks for the reply. it helped alot. by the wayhow do you get in to mercury school? , how long was it ? cost and so on? im intrested to go to school to understand these motors better. i use to sand drag quads now im into boating and i have alot of unanswered questions. thanks again jeff bush

[Terry Jackson]

It's been about 10 years since I went to mercury school. Unless things have changed, you have to work for a marine dealer who services mercury, and the dealer has to sponser you. You go the first year for class, then a year or more later you go again, after having worked the field, for your certification. Someone else here may have later info.

[delawarerick]

I think Terry is right the only way to go to mercury school is in a mercury shop or authorized mercury shop. I was selling boats and I couldnt go because I was in sales. I went to a four year tech course at night here in De and it taught just the basics plus the teacher was an omc dealer. MMI is another school thats very good but it teaches all brands. Rick

[HYDROVAGAS86]

thanks guys for the info , but there has to be a way in. its just realy sad hat i have been in this sport for about 2 years and evey time i talk to a local mercury mechanic i know more about the engines than they do. the last one i got into a spiting match with was trying to sell me a 2.5 piston for a 2.4 motor. it wasn't untill i went had him get a set of mics did i finly proved him wrong. with help like this i could see how some one would get discouraged about boating.

[mercmack]

ALL THAT HAS BEEN POSTED SO FAR IS CORRECT. BUT THERES MORE...ONCE YOU CAN FIND A DEALER TO SEND YOU. YOU HAVE TO COMPLETE A 10 OR 12 VIDEO COURSE AND TEST BEFORE YOU CAN GO TO A CLASS.. AND IF THE DEARLER HASN'T GOT IT YET, IT COST A FEW DOLLARS AND IT HAS CHANGED TWO DIFFENT TIME..SO IT GETS EXPECIVE....MERC HAS DONE AWAY WITH ITS TWO WEEK CLASS FOR THIS VIDEO FORMATE...THERES A ONE WEEK CLASS AND A GROWING SPCIEALITY TWO DAY CLASSES WITH A FEW PREREQUIRES(MISSPELLED)...THE 2003-2004 CLASS AND CATAGORY BOOK IS OUT AND AT THE MERC DEALER...
ITS GETTING ONE OF THEM TO LET YOU LOOK AT IT...GOOD LUCK ITS GOING TO BE ONE OF THOSE CATCH 22 THINGS FOR SURE...:D :D MY CERT NO IS CA 0168 GOOD TILL 2005 , I LOVED EVERY CLASS I HAVE BEEN TOO SINCE 1964, NEVER MISSED A TIME THAT I DIDNT LEARN SOMETHING...INSTRUCTOR JIM FREY IS AWSOM...:D :D :D

[O/B Dude]

I have owned 2.4's and 2.5's. I don't doubt what you guys said you learned at merc school, but I can tell you from my experience that all things considered, a 2.5 200 has more torque and better top end that a 2.4 200. The 2.5 has better porting and more displacement but still turns the same top rpms. Better all around.
Also, the 2.5 has more potential with regard to performance mods.

My 2 cents

[BigChief]

Hi guys, it’s an old topic but I wouldn’t start a new one to keep the forum clean..

i have a 2.4 200hp carb from 1981, so crankshaft rated. I’ve seen a 2.5 200, even carb from 1994. The engine is behind a Ring 21C, quite heavy boat.. Shall I feel a big difference between those 2 powerheads? I know the 2.5 should have more torque, bit what differences are there further?

[patchesII]

I know in our rule book in the stock 200 classes the 2.5 200 is at 1400 lbs and the 2.4 is at 1300 and the 2.4 can’t compete. Even with a 100 lb weight break it’s not worth showing up with a 2.4

[BigChief]

I know in our rule book in the stock 200 classes the 2.5 200 is at 1400 lbs and the 2.4 is at 1300 and the 2.4 can’t compete. Even with a 100 lb weight break it’s not worth showing up with a 2.4

Ok! So in fact, you’re telling that the 2.5 is a bit faster/stronger..

[BigChief]

The seller says it has 10-10,6 bar compression..... huh? For stock.... no way, is it?

[Merc 2.5]

Huh? What's 10-10 6 bar? Comp needs be round 120 , give or take

[FORBESAUTO]

10 bar is 145 psi, 6 is 87 psi. If all 6 is 10 then that’s good and not stock. If one is at 6 that ain’t good

[David - WI]

He's saying 10.0 to 10.6 bar for all six, I think.

[FORBESAUTO]

Ah, believe your right. Lot of the metric uses , instead of a . and threw us off:o. So he’s got 145 to almost 154. Definitely tighter heads than stock

[Merc 2.5]

Guess 1st I've heard anyone reference comp to bar , is it diff kinda guage or sumthin?

[FORBESAUTO]

Just a metric unit of measurement for pressure. Was a Mercedes master guild tech and was familiar with all the metric systems back in the day