2.4l 200hp Mercury. Can I get more HP out of it?

rjcamel2355

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Apr 22, 2015
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Title pretty much says it all on this one guys. I've a 2.4l 200hp mercury black max, I've seen that they for sure went up to 225, but haven't dug too deep to see what all needs to be done, or if I can go bigger than that.

So my question is: What can I turn this motor into, HP wise... and how do I go about doing this?

I'm sure it won't be too cheap, but I'd like to get what I can get out of it... if it lets go, then I'll get a 2.5L block, as a lot of people have already recommended that, but for the time being, I'd like to see what I can do with this one.
 

Dukedog

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Oct 6, 2009
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tha 225 2.4 built in '80 and '81 has a different front half/reeds and reed plate.. whats called seven petal stuff (dropped for 5 petal and derated to 200 in '82) but is also crank shaft rated.... 200 is a "dependable" little stem winder as is.. tha seven petal stuff does add justa tad to top end but really not justifiable to most.. tha norm five petal stuff pulls a little harder but gives up a coupla mph compared to tha seven.. 'bout tha only thing to improve it without puttin' it under tha knife so ta speak is add compression, timin', good fuel.. this won't add much, if any, to top end but will improve low and mid range.. but more important is total set up and type of boat.. some will say different but i'v been there with justa 'bout ever configuration possible in tha 2.4 and its really hard ta beat a healthy, bone stock 2.4 200 for performance "AND DEPENDABILITY" in any 2.4 other than tha Bridgeport..... if ya still determined to do some of tha butcher work google "T-Rex Cherry 2.4".... gl.
 

rjcamel2355

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Apr 22, 2015
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Thank you Duke, I'll google what you recommended and start going from there. I know a jackplate is going to help, but I'm always wanting to push it a little more (I know one day it'll bite me in the ass).

Adding compression, are we talking just good fuel/timing, or cutting on the heads?

I've been looking at some low water pickups and what not, but from what I have read unless you're running in the upper 80's+ the low water pick up is kind of a waste. I've got a WPSI gauge, and WOT trimmed up it sits at around 12PSI, I've got more trim to feed it, but IF I try it, it drops down to 8, so I've avoided doing that.

I've seen some people using set screws in the top 2/4 holes in the lower unit to keep it from grabbing air, would that be something worth doing? or do you have any information on something like that?
 

Dukedog

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cutting tha heads... but only if tha motor is "healthy" ta start with!.. do a comp and leak down before ya even think about any hot roddin'.....

unless ya runnin' it on something light and capable of 80+ then tha low water deal would be a waste... plugin' tha top 2 or 3 holes would be just as good....

boat? (main issue).. offset (no jp?).. height?..gears?.. prop?.. rpm?
 

rjcamel2355

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Apr 22, 2015
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The boat is an 84 skeeter starfire 17' according to NADA it's a 1050lb hull, no jackplate as of now, but I am looking for one (Should I get a 4", or 6"?, I'll get you a picture of where it is mounted. No idea on the gears as far as I know it's a stock 200 lower unit. Prop is currently a SS 23p quicksilver (stock prop.... I know it needs to be bigger, I'm on the hunt for one of those too) It'll turn the prop 7000+ (tach only goes to 7000, but when I got into it, it buried it) IF I let it, but I haven't, I've kept it in the recommended range, trying not to tear anything up.

Haven't done a leakdown, but from the gauge I rented from autozone compression is 125 give or take 1-3PSI depending on the angle you look at the gauge.
 

Dukedog

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Oct 6, 2009
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know that boat well... be very, very careful, life jacket and kill switch lanyard a must....... i'm sure you have checked tha condition of stringers, kickers and transom? turnin' a healthy 200 7 ta 7200 for short burst won't hurt it on that boat..... jus not to often!

jack plate (check steering cables for length) is a must... it's borderline with 200 "for" a lwp gear case.... ran tha same thing years ago with a BP on it... rigged with 6" offset, bob's, 26/27 tuned up hoss "I" (one) most of tha time... more for "quick" than top end.... can be very fast but will be a handful that can get away from ya in split second!.. mainly 'cause its short..... baby steps!
 
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rjcamel2355

Petty Officer 1st Class
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Apr 22, 2015
Messages
221
Oh, it's already to the point where it chine walks, but It isn't quite out of hand or anything. Cables are appropriately lengthed for a jackplate (both steering and shift/throttle) I'm running a hot foot, with the kill lanyard on me. It is definitely a both hands on the wheel kind of boat, I'm sure hydraulic steering would help, but It's manageable with just the dual steering cables.

Transom is stout, I've looked it over and tested it out as best as I could "standing/pulling on it" stringers and everything else seem to be alright also, I plan on spending some time and a little money on the boat/motor this fall just to get everything tip top like I want it.

So you're thinking a 6" jackplate and a 26/27 prop would give me what I'm wanting? and this may be a stupid question, but is the "hoss" you're referring to a cleaver prop? or just a 3 blade SS prop?
 

Dukedog

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Oct 6, 2009
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triton I "hoss" (http://hossprops.com/Triton1.html) was tha premier drag style prop back in tha day and is still a desired prop by some.... prop is something thats gonna be YOUR deal... everyone and every prop are gonna be different.. will depend on what your lookin' for... et's (3 and 4 blade), choppers (both big and small ear), yamaha drags, choppers cut to et's or yamaha's and etc are big now days.. there are no two props that will be same, even outta tha box so called identical props... its an adventure for sure.. i've had as many as 30+ props hangin' on tha garage wall... so beware tha "sickness!!!" your venturin' into....
 
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