I just put a weber carb on my samurai, it has stock tires, new plugs, wires, rotor, cap. just did a compression test that was fine. The carb is mounted backwards. It will not go any faster then 45-50 if i go in overdrive it just looses all power. any ideas or reasons why this is happeneing?? Thanks

- Idles nice and smooth

What condition was the carb in when you got it? is it clean or
have any water or dirt in it?

What did it come off of? is it jetted correctly?

I would guess it's running lean

Wild

Its a new Weber Carb. I set the idle and fuel mix as instructed it runs great. I'm guessing the jets should come. Set right? If not how would I go about setting them

Jets in Webber carbs are a swap out thing, you can only adjust
so much, what you really need for tuning is a mixture meter, that
runs off of an O2 sensor, or put the truck on an exhaust gas analyzer,
which will probably be expensive, but Autozone can supply a mixture
meter and an O2 sensor for about $60 (est) then you can drive and watch
the meter to see what is happening.

You might also look into the books or talk to the place where you got the carb
to see if there are any recommended jet sizes, for all I know it could be getting
way too much fuel, and gasoline is funny for the right mixture, 12.5:1 to 16:1
is the range, 12.5 for power and 16 for lean cruise, outside of that range and
she's not going to run well.

Does the exhaust smell rich under power? you might get away with you or a friend
following your truck to give it a smell test under power, how is the fuel mileage? I
realize you haven't probably driven it much, but that could be another indicator

Wild

Just an Idea,
You say you mounted the carb on "Backwards" ?

The intake manifold has two different size carb base ports, and the adaptor is offset to one side.
You may have obstructed the flow from the carb's primary side ?

When I installed my Carb, I "Match Ground" the intake Carb Mount Base (Opened Up) to the size of the gasket.
Mounted it Fuel bowl forward, as in the instructions,
and also Opened up the adaptor provided to keep the factory air cleaner set up.

In made a noticeable difference.

CAPT

Did you ever get it figured out? Mine is doing the same thing. Its mind boggling to me. Is it is like its flooding out? Thats what mine seems like, but it starts missing right between 3000 and 3200 rpm. Its also blowing wet black chunks out the exhaust. The part that's screwing with my head is it did this with the stock carb! Thats why I went weber. I blew a head gasket as soon as I put the Weber on so that was replaced with the T belt and water pump. The strange part  was the tops of the pistons were barely black. Actually I could still see the cross hatching on the cylinder walls. So I will be pulling the exhaust off and see if its not partially plugged up. Hopefully with some nasty black junk. I also have a new cap, rotor, plugs, wires, and coil. It has good compression, good vacuum, great spark, and the timing is right on.