BS 120202 0417 E1 041125 Carburetor: needle and seat replacement - green vs. red

[xeribis2014]

Hello out there

I recently bought a 398188 needle and seat kit from getmemowing on ebay. My carburetor appears to be a 791077, after confirming the date codes and types, using the BS website and looking up the part from the BS part list.

Here's my situation: I removed a red colored seat with some difficulty/resistance. I tried to install the green colored seat that was shipped to me but it was way too small and it fell out easily when I turned the carb upside down.

Am I supposed to soak the seat in solution to make it expand? Is it possible that I am doing something wrong in putting it in? I asked the vendor for an answer and all they say is I may need a different part and that the green imported seat is the exact same thing as the original part from BS.

I see two different colored seats with the same part number and it just doesn't look right. Can someone explain to me what I am not seeing or not doing?

Help!?

 

[reynoldston]

I have found on most of the newer engines its best to just leave the old seat alone and just replace the needle valve.

 

[Fish]

My parts lookup shows 2 different carbs, so You likely ordered the wrong part.

carb

 

[xeribis2014]

I agree with both replies to my post. 1, not to disturb the seat unless necessary, and 2, to be sure and order the part for the correct carb. One carb has a sponge type seat that is serviceable, and the other carb, with the wire on the needle, does not. The needle matching the non-removeable seat has a rubber tip molded into it, which provides the seal necessary against the brass face of the non-removeable seat. That is why the diagram does not show a matching seat.

I discovered that I had not been pushing the green seat all the way to the bottom of the chamber it sits in, and after taking the carb to my local repair shop and purchasing a new seat, I was able to compare the two different colors - green vs. red. The red is a factory original part: the green is an import from the country of Taiwan. Both seats were exactly the same size and both seemed to exhibit the same "sponginess" when compressed between the fingertips. There is a difference in the design of the ridges on the two different colored seats, but that's getting into engineering which is far beyond my comprehension.

When disassembling this carb, the red seat kind of crumbled when only slightly disturbed, so it was removed. I had thought I ordered the wrong parts, but my problem turned out to be a simple lack of knowledge and experience. The owner of the repair shop informed me that there is a molded-in collar at the bottom of the seat chamber - the last millimeter is slightly smaller than the inside of the chamber, allowing freedom of movement of the needle and providing a smaller diameter surface in which the seat is "pushed" in the last little bit, holding it in place - thus the difficulty in removing it.

Thanks to Fish and Reynoldston for taking the time to read my post and offer helpful advice.