Walbro Rotary carbs..WY,WYJ,WYL,WYK...Plus Zama Rotary.

[Simondo]

Walbro rotary carbs...The WY ,WYJ,WYL,WYK ...... group used on line trimmers ,hedge cutters and some blowers.
Information on the "Actual" differences between them and what carbs sub across would be good.
Most have a primmer bulb and there are a few styles of diaphragm that are needed ....so what do we know that would come in handy while working out what is what with this group then fellers ?

 

[Simondo]

The most common ones I have worked on are ..WYJ and WYL.

 

[Stump Shot]

Good post Simon, I sure would be curious to know myself. This is the only carburetor I flat out failed to rebuild properly. Was not able to diagnose what was wrong and running out of time I begrudgingly put on a replacement carburetor. Was on a little Echo trimmer, about all I remember about it. I think I might have saved it for future reference, maybe I'll see if I can dig it up. Was painfully obvious that I missed something in there, either dirt wasn't cleaned properly or some unknown to me failure.

 

[jake wells]

i got a wyl on my redmax great little carb.

 

[Simondo]

Good post Simon, I sure would be curious to know myself. This is the only carburetor I flat out failed to rebuild properly. Was not able to diagnose what was wrong and running out of time I begrudgingly put on a replacement carburetor. Was on a little Echo trimmer, about all I remember about it. I think I might have saved it for future reference, maybe I'll see if I can dig it up. Was painfully obvious that I missed something in there, either dirt wasn't cleaned properly or some unknown to me failure.

Im dealing with one at the moment so will take pics to show a few things that may help out. The primmer units often give agro and that can give running and starting issues. There is also the situation on "Some" rotary carbs that adjustment seems to be lacking ...I may be able to point to something that may or may not be known . More to follow this week once i get parts in .

 

[Simondo]

i got a wyl on my redmax great little carb.

There on a lot of smaller cc engines i deal with Jake ...Mostly they give little hassle but there "delicate" in the throttle body with a tinny plastic main jet .

 

[Simondo]

Right then....firstly . I have some working knowledge of these carbs but am "NO" expert ...so chime in if you all have info to add or can correct something i have incorrect.
To start off ......

This one is a WYJ clone on a MITOX line trimmer.


So far i have found the duck bill valve faulty and the metering diaphragm has a split across it....kit K20-WYJ should have all i need.

Check valve i scrounged from a new parts carb...


Inside the fuel pump ....looks ok but il change it out. Notice the brass metering needle valve sticking down...sits in a small chamber once together. If you flip the carb together as iv taken the image thats how it sits.



This is the rotary throttle valve ...seems ok but be "Careful" the needle jet is very small so go steady taking apart and putting together.



More soon.

 

[Simondo]

Part 2.
New carb kit has solved the purge bulb not filling with the 1 way duck valve renewed as well. I did find that a metering diaphragm split .."in its self also shows the same symptom" so check both as a matter of corse i suggest.


Back together....Note the plastic "outer" main jet tube. It has a slot on the side to let fuel out as the "inner" rotary section turns and lifts up on a cam.


Back side with impulse hole ...



No Choke butterfly so usually a paddle in the air filter housing.



OK then ..to start it and sort out the tune..This is the thing that often on "Some" rotary carbs kills the repair.
It just wont idle right ...wont start easy after the initial run..pick up smart...or you have to set the throttle stop 'Way" higher than you should to get it to not fall on its Ass !.
I have had some carbs that just seem to have a H needle....some its a jet "like this one" (approx 2 ..1/2 tuns from seated as a start point seemed to give 8500 rpm allowing for further lean down) and some theres a "air bleed"only . But not any L jet in sight !!!!!
Well if you have one that has a plastic plug or some stuff melted in the brass thing i am pointing at with a small screw driver ....get rid of the crud and see what you find. A Tiny little screw (watchmaker size) that is your L jet and should enable you to tune the carb right. The WYL carbs sometimes have just a brass plug under the seal and then your into a situation of "NO" low adjustment relying on the throttle to set the idle and transition to full speed.
Hope this helps.
Have a WYJ 192 -1 on its way for comparison to see if it could have taken the place of this WYJ 244 clone.
More info soon.

 

[Stump Shot]

Found the little rotary carburetor, turned out it was a Zama.

 

[Simondo]

Found the little rotary carburetor, turned out it was a Zama.

View attachment 66234

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The RB is not a carb i have worked on "I Think " or if i have it was on a machine that was running ok. Looks not to have adjustments from your pics Steve ? I should have put Zama in the thread to ...Fixed that

 

[Stump Shot]

Let me know if there is anything I can do with the Zama for you Simon.

 

[Simondo]

Let me know if there is anything I can do with the Zama for you Simon.

What were the symptoms you had to deal with ? a picture of the top and through the venturi would be useful to please Steve

 

[Stump Shot]

Best I can remember Simon,(this was last season) it was running short of fuel and dying out. I will get some pics and post later.

 

[Stump Shot]

Is this what you are after Simon?

 

[Simondo]

Is this what you are after Simon?

View attachment 66246

View attachment 66247

Yup...did you find the running jet ( number 3) ? there may be one in the hole with the nut round it as well ? The pic is of
your carb.

 

[Stump Shot]

I see it there now Simon.

 

[Simondo]

The difference between the WYJ 244 and the WYJ 192 that i could find available (without going through a Mitox agent) was the admission of a adjustable H needle. It has a fixed jet ..no agro if a little rich on a line trimmer or hedge trimmer . The 192 "has" got the L adjustment which is a.. 'very good thing'... so i think it may be a useful sub carb for the future. Just as a further thought ....
Im wondering if iv mistaken the clone as a WYJ carb (same body and primmer set up)...It may be a.. WYK .. as that seems to be the configuration that has a H jet. Would explain why the 192 has no H jet.

 

[ajschainsaws]

This one from a Dolmar blower 4-stroke early symptoms not running properly ok ordered in a carb kit next message won't rev at all
Comes in to me inner and outer air filter soaked in oil from engine and dust from the blowing It turns out this blower lives in tractor and loader handler clearing dust after moving wheat and barley but it's been sitting with the spout vertical in the air and the body sitting on the carb so oil leaking back through and soaking the filter

Gave everything a thorough clean wash the filters oil change and blower is singing again didn't need the carb kit but next time for sure

 

[backhoelover]

Found the little rotary carburetor, turned out it was a Zama.

View attachment 66234

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those carb have nozzle check valve in them under the fuel tube. it is not replaceable. i have had to take the jets out and use a torch cleaner to open the jet on the needle to fix them. i know just buy the cheap ones off ebay. have had good luck with them. echo training tech has a good video on these carb i see if i cant send yall a pm with the video

 

[backhoelover]

also if the primer check valve is leaking and looks good the unit will not idle. on some unit there is a metal plate on the pump side. i used to work at a local shop after my main job. had a tech come to me one time and ask if i was any good with the wy style carbs. i told him i didnt think i was a good as him and i would look at the carb. when i started to look at the carb the metal plate was warped. come to find out he puts his carb together with a drill. i took a hammer and took the warping out of the plate and the unit ran fine