1989 Mercury 2.4 Black Max 200 Service Manual

Alumaweld1990

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Oct 10, 2022
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Hey everyone!

I am looking for a copy of the service manual for the above motor. The Serial Number on my motor is 0C220333.

Background: I am having a flooding problem after having a shop look at the motor. I rebuilt the carbs but I want to check on the size of the jets in each carb and a few other settings related to idle. The motor runs great, but it is having a surge at idle from what seems normal (600-750 RPMs) to over 1300 RPMs. I'm tearing the carbs down again and checking the floats because I don't think I adjusted them correctly. Any tips on how to adjust the float height would be great!

Some fun info: The shop I took it to told me the compression was bad in one cylinder, but when I got the motor back, there was a dirt dobber nest still wrapped around the spark plug wire and the water hose meaning they never took them off... Seems to me it would be hard to check compression with your plug wires and plugs still in!

KJ
 
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Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,850
For exact carb jet sizes you will need a factory service manual, and that may not be detailed enough. A place like Crowleymarine will tell you all the possible jetsizes for your motor, which should tell you if you are running some set of correct jets.

My Mercury non-year specific service manual thinks main jets are .062, idle jet is .058 and off idle jet is .040. However, the three carbs can have slightly different jets in them for some reason.

Some of those older V6 motors do not have adjustable idle jets or replaceable floats. Hopefully your floats are good or have been replaced.

Replace the inlet needle valves and gaskets. From a Mercury Service Manual: "Float height should be even with bowl edge when inverted".
 

tphoyt

Lieutenant
Joined
Jun 10, 2010
Messages
1,261
Hey everyone!

. The Serial Number on my motor is 0C220333.

Background: I am having a flooding problem after having a shop look at the motor. I rebuilt the carbs but I want to check on the size of the jets in each carb and a few other settings related to idle. The motor runs great, but it is having a surge at idle from what seems normal (600-750 RPMs) to over 1300 RPMs. I'm tearing the carbs down again and checking the floats because I don't think I adjusted them correctly. Any tips on how to adjust the float height would be great!

Some fun info: The shop I took it to told me the compression was bad in one cylinder, but when I got the motor back, there was a dirt dobber nest still wrapped around the spark plug wire and the water hose meaning they never took them off... Seems to me it would be hard to check compression with your plug wires and plugs still in lol.
!

KJ
I had a friend told the same exact thing about his compression numbers just the other day.
The shop was also have a big sale on last years models. What a coincidence!!
I ran a compression test for him and all was well.
You just never know who you can trust.
 
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Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,420
can you see a WH number stamped on tha carb flange? tha WH is cast in and tha following number will be a hand stamp.. should be on tha flange on top of tha carb.. thats what ya need ta determine what size jets are supposed ta be in it....
 

Alumaweld1990

Recruit
Joined
Oct 10, 2022
Messages
3
can you see a WH number stamped on tha carb flange? tha WH is cast in and tha following number will be a hand stamp.. should be on tha flange on top of tha carb.. thats what ya need ta determine what size jets are supposed ta be in it....
I'll take a look when I get home and see what it was. I can't remember off the top of my head.
 

Alumaweld1990

Recruit
Joined
Oct 10, 2022
Messages
3
I had a friend told the same exact thing about his compression numbers just the other day.
The shop was also have a big sale on last years models. What a coincidence!!
I ran a compression test for him and all was well.
You just never know who you can trust.
It's crazy to me! I just don't get how a shop can send someone out the door like that. If I wasn't as comfortable with motors as I am I would never have tried to get it running and would've had to drop the $15-30k!
 
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