2.4 litre Merc carb Jetting

[bigfuelburner]

Hi all,

I'm new to the forum and I've searched the archives but haven't turned up any answers. I purchased a 1987 2.4l Merc, 200hp Black Max. It's rigged to a Cougar Omega ModVP hull and runs a nosecone gearcase with a 28 chopper. I am in the process of rebuilding the powerhead. I have noticed that the idle, vent and main jet sizes are different from the factory specifications. I would like to know what is recommended for proper jetting. My elevation is around 830 ft. I don't want to run on the ragged (lean) edge of performance. I just want a safe jetting that still will make good power and not consume massive amounts of pump gas. The compression on the motor is stock as is the fuel delivery, internals and ignition system.

Any help would be appreciated.

[jtb]

do you know what wh# the carbs have on them?
i can look up the stock spec for you but i want to be sure i have the correct carb#.
my last 2.4 was an 89 but i don't recall what WH# on the carb. it ran well with .80 or .82 mains.

[bigfuelburner]

The carb WH# is 1374-5427-C

The engine serial number is OB363479

[jtb]

The carb WH# is 1374-5427-C

The engine serial number is OB363479

look on the carb for a wh# ie. wh-28, wh-39, wh-46

[john miffco]

there is wh 13 carbs
on jetting ,,,,,,,,,
as stated stock 200 with nosecone and motor jacked up 80-82 is in the ballpark
with motor up the load is released on the motor some and will be turning higher rpms

the more rpms,,the more fuel is needed
if motor runs good as is,,,,,plugs are dry and tan colored
piston tops are moist with light carbon
again in the ballpark

if it does not have oil injection still
and you take away fuel in a 2 stroke you are also taking away the oil that lubricates the motor
if still has injection then
a few more drops of fuel pr hr
is a lot cheaper than a new motor from sticking and throwing a rod out the block,,,,,,,,,,,,,,
john

[bigfuelburner]

Ok if 80 - 82 in in the ballpark for the mains, and assuming I will be tuning using the plugs, what about the vent and idle jets? What size should they be?? Also, to date the oil injection is still in place.

Thanks in advance

[Greg Moss]

First thing to do is ditch the oil injection. If you try to turn it up the oil pump will not keep up. That thing is only marginal and will not work above 6000 or so RPM. Best to run you motor premixed.