ZAMA rotary valve carbs..whats the trick?

[RED-85-Z51]

Im so sick of these carbs, seems like I see them more and more as we near CARB Tier 3 standards...

Most work perfectly, never a problem, but let it get a little stale fuel, and they ALL do the same crap.

Primer gets very hard, hard to push iin, lots of pressure...sometimes comes out ery slowly too.

Starts on choke ,but when revved falls on its face, some will idle perfectly.

Putting in a kit, or a new diaphragm generally makes them run to some extent but they seems to want to lean out up top. Ive had luck raising the metering lever on a few but generally they just lean out.

Ive replaced the rotary part, the purge bulb plate, and a full kit, with no change on them.

I know you can remove the plastic plug on the flat side of the carb flush with the purge plate, and access a small adjustment screw, but many have nothing under that plug but a jet.

I know some have a small adjustment needle in the center pivot of the rotory part, under a brass plug...but most have nothing, and removing the plug is a PITA...

Im at my wits end...I can play with them sometimes and get them right on the bench but they come back nearly every time within a week running like crap again, and I always end up having to replace the carb...

Inversely...where is the cheapest source for RB-K70 and RB K75A type carbs? It's easier to explain to a customer that theri 200 dollar trimmer needs a 45 dollar carb, than it is an 85 dollar carb.

 

[wigglesworth]

I hate them too...my echo trimmer has one, it will start ok, but for some reason wont rev until it warms up. Then it runs way rich....then lean...i tried another carb and it worked for a while. But now its back to the same thing. Is that the replacement adjustable carb you are asking about? If so, sign me up....

 

[husky362]

take off throw against wall,,,lol

i also hate some of these new carbs, you have to be very careful cleaning them and they still wont work right , a manufacturer even recommends replacing them as its more cost effective then working on them and both you and the customer will be happy by the end results ,,,,,,, i also was told by a manufacturer a carb don't go bad ,,,,,,,,,these collage educated idiots need to get in the real world

 

[Bowtie]

8lb sledgehammer fixes the problem Red. Do you know how to run a sledgehammer?

 

[RED-85-Z51]

TTT for shoddy carbs...

 

[volks-man]

hijack

hey red,

while you are on carbs, would you happen to know of a fully adjustable carb to fit my echo 230 trimmer?

 

[logging22]

Having some of the same problems. Keep us posted if u find a solution.

 

[RED-85-Z51]

hey red,

while you are on carbs, would you happen to know of a fully adjustable carb to fit my echo 230 trimmer?

I wish I did brother...these things are giving me fits.

Like I said, there ware ways to adjust many of them...it just doesnt always fix the problem.

But they do beat the hell out of the old WYJ carbs...who remembers those abortions?

 

[volks-man]

i havn't had a single problem.

i only want to remove the cat muffler and tune it properly.
did echo ever use an adjustable srm230 carb? i'd just order that one................................

oh, and porting may come later.

 

[bec98x]

something new to me

I just started working at a new repair shop and they said they had the same problems until they started cleaning the carb parts in a sonic cleaner(similar to jewelery cleaner) They said it has increased the percentage of carbs taking the rebuild by 50%.

I have used it myself several times and am impressed how few problems I have had.

 

[kattcutter]

I guess this is the same carb that is on my Poulan SM4218AV. Just this weekend it has started acting up. It will start & idle, but won't run at full throttle.

Tried spraying carb cleaner down the throat while running at WOT, but didn't seem to help much. I see I can buy a replacement carb for around $26 + ship on the net. (Zama W-26).

Should I try to clean/rebuild it, or just go w/ a new carb at $26?