testing diaphragms

[DEmily]

Hey all,

Just had a quick question. I am still running rich, so I decided to do yet another cleaning on the carbs. I found 2 of the pilot jets to be plugged up. I cleaned everything out again and plan to put on in-line filters in. While cleaning my carbs I checked my diaphragms by pushing the slide up and holding my finger over the hole on the carb that allows the diaphragm to drop. One diaphagm stayed up until I released my finger from the hole the other three slowly dropped. Obviously I have a slight leak in those diaphragms. When the diaphragms dropped it was very slow. Should this be enough to warrent new diaphragms?

[TopCatGr58]

Hey Dan,

The slides are supposed to drop very slowly, there is a small vent hole in the middle of the metal slide cylinder that vents thru, and so it's normal for them to slide down, they won't maintain complete vacuum. So, the one that won't slide may be clogged, or the inside of your cylinder may be slightly gummed and needs a bit more cleaning to keep it from sticking UP! Also, check your springs for evenness in length. Without holding down the air hole, push the slide up with your fingers and see if you can feel any binding or stiffness in movement when you get near the top of the travel and compare to the other 3. Okay, HTH.
T.C.

[skids]

I disagree with ya TC. The small hole in the bottom of the slide leads to the area above the diaphragm to raise the slide during differential vacuum. The oval hole in the top of the inlet bell perimeter "vents" the area below the surface of the diaphragm.

Originally posted by TopCatGr58
The slides are supposed to drop very slowly, there is a small vent hole in the middle of the metal slide cylinder that vents thru, and so it's normal for them to slide down, they won't maintain complete vacuum.

[skids]

I forgot to answer the original question...If the dropping of the slides is very slow, I think that it wont make any difference because there will be "replacement air movement" to make up any that is lost through slow leaks.

[TopCatGr58]

Hey there Skids,

Thanks for clarifying that, I haven't had the tops off mine for a while, thought I remembered a slotted vent up there, but was just looking at some (dare I say...extra diaphragms I have!), and remembered and checked for that hole in the slide. I guess my ignorance is showing, apologies to the GURU's!!!

Stepping back under the shade of my tree....
(shadetree survivalist!)
T.C.

[Geezer]

Re: testing diaphragms

Originally posted by DEmily
Hey all,

Just had a quick question. I am still running rich, so I decided to do yet another cleaning on the carbs. I found 2 of the pilot jets to be plugged up. I cleaned everything out again and plan to put on in-line filters in. While cleaning my carbs I checked my diaphragms by pushing the slide up and holding my finger over the hole on the carb that allows the diaphragm to drop. One diaphagm stayed up until I released my finger from the hole the other three slowly dropped. Obviously I have a slight leak in those diaphragms. When the diaphragms dropped it was very slow. Should this be enough to warrent new diaphragms?

Go spend the 7 or 8 bucks for a tube of Yamabond 5 and squirt a little into the hole in the diaphagm (after degreasing it.) let it dry over night and it'll be as good as new.

Geezer