Promax carb?

[mercrazy]

Can wh-22 carbs feed a 225 promax? I’m sick of computers.

[rjdubiel]

Sure can. Just start with main jets around 84-86 and go down from there. You will be safe there, as you go lower remember there will be a lean spot at mid throttle if you get low enough on the main jets (two circuit carbs, no mid range jets). I would go up on idle jets also, go to like .056 or so.

[pcrussell50]

Can wh-22 carbs feed a 225 promax? I’m sick of computers.

I hear ya, mate.

I'm from the fuel injection generation. My track car has the Bosch style fuel injection system that the two stroke EFI Mercs has. I have an interface to the service port of the PCM to let me tweak settings a needed. I never even touched a carb until I got my first boat back in 2008.

Even still, for my uses as a boater, the simplicity of carbs is like magic to me. It's satisfying to link and sync, and then get the timing pickup just right. I don't put in nearly enough hours to worry too much about fuel economy.

I don't know if it's anything to go by, but I swear I see way more questions from people having issues with their 2.4/2.5 EFI two strokes right here in this SnF Technical Discussion forum, than I do people having carb motor issues.

-Peter

[Merc 2.5]

Ive ran wh 22s , 46s , 20s on a modified promax, ported , 150 compression the works, depending on weather 82 or 84 mains and 60 idles with wh20s currently. Personally I like the 20s and the 46s but the 22s r good to.

[mercrazy]

Can I use carbs from a 3 liter 225hp? Seems to be plenty of those. I can’t find wh20s. I want to make a 245hp with a ff block. Also heard I could use Yamaha carbs. What would be best?

[Merc 2.5]

Can I use carbs from a 3 liter 225hp? Seems to be plenty of those. I can’t find wh20s. I want to make a 245hp with a ff block. Also heard I could use Yamaha carbs. What would be best?

I haven't tried but I hear it's hard to get a good runnin tune with 3L carbs but don't take my word for it on that. 245 hp with a ff gonna need alot portin and cuttin and compression. Wh46 carbs also run good. Alot say they can't tell a difference in 46s or 20s etc. Maybe depends on combination of everything not sure. U can get u sum 245 carbs and try those

[tlwjkw]

3 liter carbs are a pita ona 2.5 period.. tried a coupla times... not worth tha trouble imo.. a very few have had a little success...

[25two.stroke]

3 liter carbs are a pita ona 2.5 period.. tried a coupla times... not worth tha trouble imo.. a very few have had a little success...

I 2nd this.

[mercrazy]

Where can I find 245 carbs? Are they wh15 or wh20 only?

[25two.stroke]

I think both 15s and 20s came on 2.4

WMH-36 came on a 245?

[tlwjkw]

I think both 15s and 20s came on 2.4

WMH-36 came on a 245?

crap shoot on which wh ya got ona 2.4....

245's could be several wmh numbers.. think it depended on "whats in tha box" when it got put together deal.. mostly depended on jetting more than anything else... was told this by retired merc guy long time ago....

[mercrazy]

So what is the main factor in a good carb for a 245? Throat size? Do all wmh carbs have same throat?

[tlwjkw]

think venturi size is same but tha internal passages are a little different... believe there were two sizes of venturi openings.. mostly differed with some 135's and 150's... all 175 and better were a tad larger.. even some 150's had same as tha larger on some models.. we used a coupla different wmh's: 16's primarily (when they could be identified) unlike tha wh's.... there were a coupla others but can't recall tha wmh number.. basically anything that came ona 200 or better would work with tha right jetting............

[tlwjkw]

got lucky and found an old thread that MRCRSR had some very good infor 'bout tha carbs....

Mercury Tech WMV-WMH carb info (https://www.screamandfly.com/showthread.php?322210-WMV-WMH-carb-info)

[25two.stroke]

I probably have some WMV-18 carbs from a 2.5 200. If you would wanna start with those just send me a pm and I will go look in my shop.

[mercrazy]

Let me hunt through my pile. I’ve got several sets of wmv but don’t know what number. I always thought they had to have a bigger opening. Thanks

[Merc 2.5]

In my personal experience with .modified 2.5s and making power along with rpm the wmv 18s wasn't even close to the wh46 or wh20s. I took 46s off and immediately put wmv 18s on , got it jetted , the idle was cleaner and gas milage was a ton better but that was it in my trial run , and I think we can agree that gas milage and HP dont belong in same sentence on these old 2 strokes. I didn't waste any time putting the 46s back on , and when I went from 46s to the 20s I have on now, I seem to lost little hole shot but was better everywhere else , now that I've had time to experiment with jets, it's tuned now it has good idle, great hole shot and great mid-wot. I've got another guy that I talked into tryin 46s and he took wmv18s off and said he wont go back either. To each his own , that's why we try things. What works for me may not for you visa versa. My motor was originally a 240 sport jet ( 225 promax) ported ,compression etc etc. I have 86 mains and 60 idles in now and it leaves out hole like efi turning 28 chopper on bass boat to 7k