Differences in the merc 2.5?

[Traefinn123]

Hey guys I have a 200 2000 2.5 efi 200l runs like a scalded ape on my bullet and strong ! I have another block I would like to put on my engine to run while I build my Ff block .. I checked compression other day and have about 80-90 lbs compression and I was told that block only had about 110 lbs factory .. I want to get the compression up and keep this engine going but my question in what is the real difference between like a 200 and the 225 2.5 efi ? Can I change the port height and make more power or what is the best way to go about building this engine to get the most out of it?

[Merc 2.5]

Before we get into porting and build etc , merc 200 comes average 125lbs stock from factory. Ur lookin to see about 115 lbs or above (120 ideal) with stock heads with 10lb variation max , if all cyl has 80-90 lbs I'd get a diff guage and retest , if results r the same and a decarb dont help much , ur lookin at a rebuild , motor is prob good for rebuild with minimum $ but if u run it with low compression then u will tear sumthin up , (crank, rods) eventually and cost alot more

[Traefinn123]

I tested it with harbor freight gauges hot battery wot .. cold didn’t have time before work to pull it out and get it hot but it has low compression I tested it awhile back after I fished and it was all about 10 lbs more still in the 90”s .. I want to pull it down and rebuild it but I’d like to build it rite and try and get the most out of it while I got it apart I know u can cut the ports and get more intake or exhost I was wondering what I could do besides opening up the exhaust cavity to get more out of it like fooling with the port heights

[22R]

I tested it with harbor freight gauges hot battery wot .. cold didn’t have time before work to pull it out and get it hot but it has low compression I tested it awhile back after I fished and it was all about 10 lbs more still in the 90”s .. I want to pull it down and rebuild it but I’d like to build it rite and try and get the most out of it while I got it apart I know u can cut the ports and get more intake or exhost I was wondering what I could do besides opening up the exhaust cavity to get more out of it like fooling with the port heights

The Horrible Freight compression gauge is junk...bad design. The Schrader valve is located near the gauge not near the fitting that threads onto the plug hole. Get a good gauge and retest. Look up harbor freight tester on youtube a guy did a good video on why it does not read right. Gauge is ok design bad.

22R

[tlwjkw]

but my question in what is the real difference between like a 200 and the 225 2.5 efi ?

225 will be tha pro max unless ya lookin' atta 3.0 225?.. not to compare with tha 200 production.. several things different.. rod slots, front half/reeds, ecu etc...

[Dave Strong]

Hey guys I have a 200 2000 2.5 efi 200l runs like a scalded ape on my bullet and strong ! I have another block I would like to put on my engine to run while I build my Ff block .. I checked compression other day and have about 80-90 lbs compression and I was told that block only had about 110 lbs factory .. I want to get the compression up and keep this engine going but my question in what is the real difference between like a 200 and the 225 2.5 efi ? Can I change the port height and make more power or what is the best way to go about building this engine to get the most out of it?

Try a known good compression tester before you worry about those numbers.

Dave

[FORBESAUTO]

Your 2000 200 will be an O-Ring head motor and will have CDM style ignition. Great engine and a lot can be done to make good power. But before I went to doing much internal modding and changing port timing that requires more rpm to reap the benefits. I would verify leak down is good/ your compression gauge is off. If mota is shot then have at it, if still healthy, I would start on bolt on type mods like swapping out cdm ignition to switchbox type that will allow more rpms in future without worrying about rev limiter. Depending on how many rpm you want to turn you could also go to light weight 16 amp setup, drawback on 16 amp would be your electrical needs. Get heads cut to bump up compression. Maybe get ya a light weight cowl to allow for room to add intake spacer and CCMS reeds. If ya still won’t more, your now set to have a reputable guy mod internals to your needs/expectations