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Could use some help to ID some carbs

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brandonw

New member
I’m trying to check\verify my

I’m trying to check\verify my jet size. I have a 1988 Black Max 150.
According to the manual I should have a WH1-1 through WH29-3 type of number stamped on the base of the carb.
I can see a WH that was part of the mold but no numbers stamped anywhere near the WH.
All 3 carbs have 1374-5427C molded in the base.
The other numbers that appear to be “stamped” are
40-11378
40-21378
40-31408

Can anyone explain to me what WH numbers these are or what the default jets sizes should be for these?
Thanks in advance for the help!
 
"Brandon, are you the original

"Brandon, are you the original owner of this motor??

The casting numbers come up for a Walbro WH-46 carb - and you won't find that in your standard parts list.

Those were used on Merc's Bridgeport racing engines during the 80's/early 90's.

So either someone really goofed at the factory or someone tried to hop this motor up at some point..."
 
"Graham, Thanks for the infor

"Graham, Thanks for the information.
No unfortunately I'm not the original owner. Although I’m not surprised that someone tried to get a little extra out of the motor. From all the paperwork that I have on the boat I believe it has lived in Colorado all its life. I’m sure they we trying to make up for the altitude.
I assume that these carbs are the same as the other 2bbl Walbro in that the idle jet meters air not fuel? It looks like they put smaller jets in all the way around not realizing that they were actually causing the idle circuit to run richer, which would explain my problem of loading at idle.
Again thanks for the info!"
 
These were pretty much the sam

These were pretty much the same design as other Walbro's. The WH-46's were built for Merc's 2 litre engines (which the 135/150's including XR2 models were).

Have read that you could squeeze up to 200 horses out of the 2 litre models and this carb was part of the required kit..
 
I’ve seen some claims of that

I’ve seen some claims of that in forums but not sure on all the modifications that have to be made.
If I can just get the 150 out of it on a consistent basis I will be happy with that.
I looked at the vent jets last night and those are still the standard size. Do you know how much impact those have on performance?
To me when I hear “vent” I think of float bowl vent and seems odd they would have a jet for that. But maybe they are not float bowl vents?
But if they meter air again I would think they would need to be larger for the altitude but the manual says to reduce them by .004.
Any thoughts?

Thanks again for all the info.
 
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