Carb rebuild but the metering diaphragm is too high

[aljewett]

I picked up a really sweet Homelite XL-2 last week, and just going through the usual stuff to get it running. Carb kit from Amazon, everything fits and looks correct except for the nub on the metering diaphragm. It appears to be about 1/16" too high. I'm thinking of just reusing the old one...it's in pretty good shape. Or....has anyone tried grinding theirs down to fit?

 

[hotshot]

Jump to 8:30, in the video below.



I’d throw that chinesium kit in the trash & order a Walbro kit # K10-HDC, assuming you have a HDC model carb.

 

[aljewett]

I’m thinking the same thing. Thanks.

 

[Vintage Engine Repairs]

Just file it with your depth gauge file.

 

[aljewett]

I’m thinking maybe a Dremel?

 

[Vintage Engine Repairs]

No need, it’s literally a pass or 2 with the file. Super soft

 

[Okie]

Quite common about replacement needle valves now days.
When I see such I inspect the old one with a magnifying glass and if I re-use I do the input pressure testing after cleaning the seat.
Sometimes even the body of the replacement is wrong size in diameter. The new replacement ones needs closely inspected for proper size and first compare to the old one being removed. Also do not assume that the one being removed was a OEM and operating correctly. Proper setting of the lever REQUIRES that the needle valve is the proper length.
If length only is wrong of the replacement you can dress it with a file, soft material.

I prefer to do a pressure test BEFORE and after taking the carb apart.
Another heads up in this area IS:
Also some of the buttons (that operate the lever) on the replacement Diaphragms are not the same size as the one being removed. (and not even useable)
You might be removing a Chimease kit and installing a real deal kit or vice versa so pay attention to all closely.

 

[Gord404]

intreresting- never really paid much attention to that, now I will

 

[aljewett]

Too much nub = too much fuel = too rich

 

[Old2stroke]

I have seen rebuild kits that have been installed with the diaphragm upside down and the nub on the disc and the nub on the other side are never the same size.

 

[Cliff R]

Coming up on 50 years working on carburetors, all varieties and the only advice I can give here is to buy OEM rebuild kits for Zama, Walbro, Tillitson, etc. Sometimes it takes a little more searching to find them, and you have to read the descriptions closely to make sure that you aren't buying cheaper replacement parts and not OEM. Same thing with carburetors. I've had zero success with aftermarket small power equipment replacement carburetors.

Here's a quick story where I screwed up and how it turned out. My Echo string trimmer was flawless for nearly 20 years then the throttle started to stick. Turns out that it used one of those carburetors with the plastic hour-glass looking throttle plate which I'm not overly fond of. It was broken and hanging up. So I go on Amazon and find an add that was very carefully worded to make you think you were buying a genuine Echo replacement carb. It was also about $35 so I assumed it wasn't the $10 Chinese special everyone else was selling. Well SOB it showed up and was a Chinese copy of the OEM carb, I was just fooled into paying $20 too much for it. So I decided to just give it a go anyhow since it was for my own use and not for a customer. It fired up and ran well for about 3 weeks then bit the dust and quit working. So I go back on Google and find a genuine Echo replacement carb. It was closer to $50. I put it in place and it's been flawless for about 5 years now. Lesson learned that I already knew. Stick with OEM and you'll save time and money in the big scheme of things.....

 

[aljewett]

I ended up ditching the chinese diaphragm and got an OEM carb kit. Flawless operation, just like new.