What size is the large O ring in OHG mixer

[remco]

What size is the large O ring in OHG mixer.
Thanks Remco

[C3H8]

Measure the old one with calipers unless your talking diameter. This is not really an o'ring. It's just a straight piece of rubber like material. There needs to be a small gap between the ends when installed to allow the piston to move other wise vacuum will prevent the piston from moving up down. many people think the seal is broken but it's not. I can't remember the material thickness. Maybe someone else knows it.

[Maddcarson]

What kind of straight rubber would it be called? Or what is I used for normally so I can try to find a few strips and find the that will fit?

[C3H8]

I have a local dealer with a couple of used ones in stock. I'll go by there in the next couple of days and verify the size. I can't verify the material. It appears to be regular o'ring material. Maybe one of the other members know what it is made of.

[C3H8]

I should have also mentioned, check the colour of the secondary spring in the regulator. To use it with an OHG mixer it should be orange in colour. Blue works with IMPCO 425. Orange, the 1/2" WC, works with the X450.

[C3H8]

OHG X450 O'ring data.

Diameter: 2.6MM or .098"
Length: 12.25" or 31CM or 310MM

Trim length to allow small gap between ends. Approximately 1/32" to 1/16"

Material: Unknown but appears to be the same as a standard black o'ring.

[Maddcarson]

Is there any benefit to making the gap smaller than 1/8th?

[C3H8]

What most newbies don't realize is that this gap is the air vent that allows the piston to move back down after vacuum pulls it up. Many think the o'ring is broken and will either try to glue it together or put on a similar o'ring that is intact. The gap is important to provide proper lift and to allow the correct relief when the throttle is closed allowing the piston to lower down again. Too big of a gap will result in hesitation or stalling. Too small of a gap will result in excess fuel on decel or even flooding of the engine which could cause stalling. Unfortunately I don't remember the exact gap, but yes, too large of a gap is not good.