wich carburetor is original for a '51 MM?

[TvdWerf]

I have 3 different carbs, 2 engines, and try to make both complete running, but which parts are original for these engine's?[frame][/frame]I bought this engine in parts, it is the one who was factory mounted.
[frame][/frame] this one was also in the box, and incomplete.
[frame][/frame] And this one was number 3...

[mike.perry]

The manifold is the correct one for Karl's engine.
The carb in photo 2 is a SU H1 semi downdraught for a Series II 803 engine. The float chamber is at an angle.
The 3rd photo looks like the correct carb, SU H1 horizontal float chamber[frame][/frame].
Is it a USHM2 or 3 engine? On the 2 the float chamber is at the rear and on the 3 it is at the front.
Note also that it is important to have the strap fitted to the air silencer and secured to the accelerator cable bracket to prevent the trunking from fracturing with the vibration of the air silencer as shown in this photo.
I see from other photos that it is a USHM3

[alexandermclaren]

air silencer?

[mike.perry]

Workshop Manual P A2-3, Item 90.

[TvdWerf]

Thank you Mike, I see I have another missing part...
And an unused spare, carb 2 I will never use.

[karlcouchMM1952]

Yes thats the type of manifold Im after Mike.

The carb I have on my car 1952 is the one that you have in your option 3 photo. I have attached a pic of my engine which has the correct dizzy, carb and air silencer. If tried to do research on each item I added to the car... so figers crossed its all correct.[frame][/frame]

[TvdWerf]

In that case, my air filter is also different..[frame][/frame]A picture from the other side...

[stevey]

your air filter is the export oil bath type for the MM, so is correct.

[TvdWerf]

In that case there are no missing parts, i could not find any strap in the boxes with parts...
the other carb does not have any filter, but maybe I find another one somewhere.

It is always nice to have a complete running engine as spare

[mike.perry]

The strap should be around the middle of the air silencer to give it more support. See photo of my engine

[karlcouchMM1952]

Hi Mike,

Your photo hasnt uploaded?

I thought the air silencer (not oil bath) was correct? You learn something everyday!

[mike.perry]

See photo on posting Sat 2nd March, 9.57
Air Silencer Home Market,
Oil Bath Filter Export Market
I expect that there are exceptions!

[karlcouchMM1952]

Ahh, sorry. I see what you mean now!

[TvdWerf]

I bought a rebuild kit, and took the card in parts.
In the manual they describe a spring, and I did not found it.
So I lifted the top from number two, and found the spring, but a different housing.
This spring will never fit in the original one, is this correct?
Is it possible some types were without a spring?
Number 2 had only a top screw, not the complete brass piston damper...[frame][/frame][frame][/frame]
What is the right combination, with damper, or witgout, and with the spring or without?

[Scott]

There's no spring in the Series MM carby.

The strap for the oil bath air filter attaches to the aluminum casting between the filter & carby, just above the dashpot area. It's basically just a strip of metal about 5/16" wide IIRC.

**Edit:
Carby photo #1 has the strap. It looks little misshapen but that's it.

[mike.perry]

For USHM3 engine H1 carb, horizontal float chamber, damper, no spring, float chamber in front. Home market air silencer, export oil bath air filter