1993 200 H.P. Carb 2.5L Mods

**Hydrodreams** · 09-24-2018, 06:27 PM

So I purchased a 1993 200 H.P. Merc 2.5L carb engine. (Back up project engine) Compression is 120-125 across the board. The engine is completely stock with just under 250 hrs. What mods would do you engine guys recommend? Bolt ons I can handle but when it comes to the inside work I will leave that to the pros..whoever that might be??? i don't need a triple digit temperamental bullet. I would like good acceleration, reliability, and be able to do at least 80 with my Viking. Alright engine guys...GO!

**Merc 2.5** · 09-24-2018, 06:36 PM

Hands down best improvement is cutting heads to 34cc. Will require rejetting anf 93 octane gas

**Merc 2.5** · 09-24-2018, 06:38 PM

Also along with that you need get with chris Carson (vendor here)and get you some reeds and stuffers , and you will think u have a different motor

**Hydrodreams** · 09-24-2018, 06:50 PM

Cool thanks guys also thanks to the mod for moving this thread FNG mistake

**Merc 2.5** · 09-24-2018, 06:55 PM

B4 you go cutting the heads ,you mite wanna read up on "how to" read plugs and piston tops to determine the rich or leaness to the motor. You can burn one up quick. But with carbs should be a simple bolt on mods

**Hydrodreams** · 09-24-2018, 07:05 PM

Originally Posted by Merclover

B4 you go cutting the heads ,you mite wanna read up on "how to" read plugs and piston tops to determine the rich or leaness to the motor. You can burn one up quick. But with carbs should be a simple bolt on mods

10-4 will do! I like the milled heads approach. I have always been fuel, fire, and air improvements vs going internal. That's on the auto side though I have never modified an outboard. Completely different animal I know.

**Merc 2.5** · 09-24-2018, 07:17 PM

It's all in some ball park anyway. Just remember for ex ,if you have 78 jets now I'd start with prob a 84,and start reading from there, but dnt forget the reeds and stuffers ,those mods go together like peanut butter and jelly

**Hydrodreams** · 10-06-2018, 08:01 PM

So my 93 turns out to be a 91. No worries still happy with what i got for the price and condition. That being said the serial# is 0D021738. I cannot find a FF or EE on the block. Yet I do see a U where other pics in threads have shown the FF. Any input guys?

**Merc 2.5** · 10-07-2018, 06:29 AM

91 was a 1 yr only motor. Its has the big 14 pedal front half, should anyway, I heard those r very strong motors, not sure they started stamping blocks yet? Maybe n 92 and on? Not completely sure bout that tho

**tlwjkw** · 10-07-2018, 07:36 AM

that serial no. shows ta be a 2.0 motor?.. is tha number on tha clamp or on tha block?

**nitro_rat** · 10-07-2018, 08:06 AM

Originally Posted by Hydrodreams

the serial# is 0D021738.

I agree with tlwjkw:

Originally Posted by tlwjkw

that serial no. shows ta be a 2.0 motor?.. is tha number on tha clamp or on tha block?

Look on the top of the block, above the stbd (right side) cylinder head. There should be a welch plug (freeze plug) with a number stamped on it. This may be different from the nuber on the clamp if the powerhead has been changed!

Originally Posted by Hydrodreams

I cannot find a FF or EE on the block. Yet I do see a U where other pics in threads have shown the FF. Any input guys?

FF is the hot topic right now. A lot of guys think this block is identical to the 225 Pro Max block. These were '96-up, no concern for your motor.

Other stamps are: BB 150, CC 175, DD 2.4 200. There are a few others but they're EFI or race which that motor is not!

**rock** · 10-07-2018, 08:12 AM

They are similar in porting to the 200 Promax. The 225 Promax is a NN.

Rock

**Hydrodreams** · 10-07-2018, 02:39 PM

Sorry guys spec aren't what they use to be and the serial# tag was pretty jacked up. So here is a pic of the freeze plug on top of the engine. The number doesn't come up in my lookup so I have no idea what I have lol! Any info would be appreciated!