# Want experts opinion on metering diaphragm



## glenjudy (Aug 26, 2006)

After years of cleaning, re-kitting 2 cycle carbs, I've almost come to the conclusion that the main problem with these carbs is most always the stiffening of the metering diaphragm, the pump diaphragm most always seems to be pristine and the metering needle is good.

Anyone have an opinion on this?
I'm talking about a thorough cleaning and just installing a new metering diaphragm.
Thanks,


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## 30yearTech (Sep 14, 2006)

Many times you can get by with just a new metering diaphragm. 

I however look at the possibility that any of the other components may fail in the near future. To eliminate this as a possible issue, I usually use a kit if I am going to tear down a carburetor. The difference in price is just not enough to make a real difference. I always replace the metering arm, pin and needle as well. Adjusting them is easy and never has been a problem for me.

I am finding that on many of the newer carburetors, you can have issues with non serviceable parts, such as leaking High Speed check valves and wear on the ramps of rotary valve carburetors. In these cases, it's much easier to just replace the carburetor then to waste a bunch of time trying to make it work right.


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## glenjudy (Aug 26, 2006)

30year,
You're right, I thot after I posted I should have mentioned I would do this only on my stuff, I always install entire kit on someone else's.

Appreciate your reply,
g


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## geogrubb (Jul 28, 2006)

I agree with everything except the metering arm, as most posters on the forums requesting info are not mechanics and as such do not have the knowledge to adjust the metering arm. I refer to homeowner units only, the homeowner gets the idea "i need one of those", buy a piece of equipment, uses it once a month and leaves old fuel in it and guess what, it won't run. He/She installs the new kit, does everything per instructions, and "now" its time to adjust the metering arm, from that point forward everything goes down hill. Have a good one. Geo


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## 30yearTech (Sep 14, 2006)

geogrubb said:


> I agree with everything except the metering arm, as most posters on the forums requesting info are not mechanics and as such do not have the knowledge to adjust the metering arm.


Geo, you and I will never see eye to eye on the metering arm. 
Of course if the carburetor has very little use and has just been sitting up, then most likely the metering diaphragm is the only part that may need replacing and some clean up of the old fuel and or varnish. By all means, leave the metering needle and lever alone.

If the carburetor has had good use, then aside from the diaphragm this is one of the few moving parts in the carburetor. It is activated with every movement of the diaphragm and subject to excessive wear. I have seen the metering arm worn paper thin on the end where the diaphragm contacts the arm. I have seen the ends worn and broken off at the metering needle. If you replace all the parts in the carburetor, but reuse an old worn metering arm, you really need to readjust it to take up for the wear. Might as well use the new one, it's included in the kit.

I have always replaced them, even 35 years ago when I was first starting out (technically not a mechanic yet). I have never had any issues adjusting them. It simply is not rocket science and I don't believe you have to be a mechanic with 30 years or more experience to set one. If you can follow instructions good enough to successfully tear down and reassemble one of these carburetors, then you should be able to adjust the tab to the correct setting. Just follow the directions. At least try it, you can always put the old one back in if you just can't make it work. 

Geo, don't you have a picture of the throttle linkage for bgrantsboyz and his Tecumseh carburetor. I have been searching for a drawing or picture, but I can't find anything.


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## geogrubb (Jul 28, 2006)

30Year;
I agree with you if the arm shows any wear. When I grow up I want to be just like you(lol). I'll check on the linkage for bgrantsboyz. Have a good one. Geo

I checked, I posted 2 different times and got a thanks from the last one, my post;
The manual # is 695933, if you do a Google for Tecumseh 685933 it will show a link to it. Have a good one. Geo


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## glenjudy (Aug 26, 2006)

You were the two experts I hoped would reply.
Thanks guys,


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## geogrubb (Jul 28, 2006)

glenjudy said:


> You were the two experts I hoped would reply.
> Thanks guys,


glenjudy;
30year is the expert, I just steal his info and act like it was my idea(lol), hopefully he won't come all the way from Central Texas and kick my butt. Have a good one. Geo


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## 30yearTech (Sep 14, 2006)

geogrubb said:


> I checked, I posted 2 different times and got a thanks from the last one, my post;
> The manual # is 695933, if you do a Google for Tecumseh 685933 it will show a link to it. Have a good one. Geo


Hmm., I see that now. He posted a new thread on 1-27 asking for more help. I wonder if he got it figured out....


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