Merc 200 Performance Mods

[RAYLES]

I was getting ready to rebuild my 98 200 efi when I stumbled upon a cheap rebuildable 91 2.5 200 carb motor with 7 petal front. Also appears to have porting similar to a pro max but, I'm not 100% sure on that. Does anyone have any ideas on what performance mods can be done on my rebuild to satisfy my need for speed in my 96 Bullet 20XD. Any input would be greatly appreciated.

[RAYLES]

I guess I should have stated that I was considering using the efi setup on the 91 motor with the 7 petal front. Would this be the best choice and if so, what other mods should be considered? ECU programming? tuner? porting? heads?

[1outlaw]

You either need to talk to Jay at JSRE http://www.jaysmithracing.com/

Or talk to Big Boy Just post he will reply http://www.fastbass.com/forum/viewforum.php?f=2

These guys know 2.5's.....:)

[us1]

Porting is the way to go but you will be limited on RPM by the heavy flywheel.

[150aintenuff]

find a fleplate style red one flywheel off of a 2.0L 150 circa 1989 vintage.. that will help or go with custom light weight flywheel and 16 amp charging system and Simon 50 Amp alternator kit.. OR you could always just buy a 300X 104 should satisfy you in the speed department, assuming that the B&WB test of that hull with the 300 is repeetable

[RAYLES]

Thanks guys for the feedback. It looks like I'm going to be rebuilding my stock 98 200 EFI. What would be the best mods to use for this motor to keep it dependable but, still increase horsepower and turn in the area of 6800 RPM's? I already intend to put on a low-water pickup and raise engine height. Would I need to change anything such as the porting or have the ECU changed to acheive this? Thanks again for the feedback.

[us1]

Port it to 225 specs, open up the rod slots, recurve the ECU and go to 33cc heads.

[Burke Kilgour]

Doesn't that year have exhaust reliefs?
I have one here with a 7 petal front and exhaust reliefs. Just curious.............

[RAYLES]

The 91 model I was considering to build does have what seems to be reliefs with a 7 petal front but, the 98 does not. Is it better to have them? Yes or no, please explain as I am not that knowledgable about the differences between years and models. Thanks....

[The Big Al]

http://forums.screamandfly.com/forums/showthread.php?t=94712

[us1]

The 91 model I was considering to build does have what seems to be reliefs with a 7 petal front but, the 98 does not. Is it better to have them? Yes or no, please explain as I am not that knowledgable about the differences between years and models. Thanks....
If you are going to port the block you can make the most power without them but you still can make more power with a port job even if you have

[RAYLES]

Thanks alot guys for the info. It's starting to make sense to me now. John(us1), when you referred to porting to 225 specs I assume you are talking about the PM. If so, could you post or email me the port map or specs you are referring to. Thanks again to all those who have helped me and possibly others with this.