# Ryobi BC30 Trimmer



## Sir Thomas (Dec 7, 2013)

I have a Ryobi I'm working on. The serial number is rubbed off. All I know is that it's a Ryobi BC30 2 cycle Trimmer. I cleaned up and rebuilt the whole thing. Not sure if everything on this one is as original or if it's been modified. Everywhere I look for info on this has the Walbro Carb with the Primer body attached. This one has a Primer Bulb detatched. I got it running but only with the choke on. When I release the choke, it would die. I went back and took the carb apart again and checked to see if it's clogged anywhere. This carb is different than any I've worked on before. Should there been any flow through the tube in the first photo? I haven't gotten a rebuld kit on this because I want to make sure that the carb is the problem.

















(Additional Info 1/11/14) This is some links showing the carburetor online: http://wem.walbro.com/walbro/CategoryImages/WYC.jpg
http://www.ereplacementparts.com/images/part_308028001-1_med.gif

I have gone through and thoroughly cleaned the carb with Seafoam cleaner. I reassemble and hooked everything up but didn't put the throttle plate on it to see if any fuel comes up the tube in the first photo. Nothing.


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## Sir Thomas (Dec 7, 2013)

*Defective Primer Bulb*

When I was testing the snap n primer bulb with a new filter and new line directly in a glass of fuel, I found that it doesn't have much draw power. The bulb is very slow in returning to shape with fuel in it. That may be part of the problem with purging the carb. Connected to the carb, the bulb is half full of fuel. If it did it's job, I'd think it should be full. Do they vary from one to another? This one was sold on ebay as A056013 Genuine Zama Snap in Primer Bulb MTD 791-683974B Ryobi 683974B by ICPower1. Which is a better snap in bulb? Good thing I didn't by in bulk.


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## Sir Thomas (Dec 7, 2013)

*To do or not to do*

I need help. Anyone familiar with the Walbro carburetor that I had posted previously. I need to know before I spend anymore money on this unit if the fact that no fuel is coming up through the jet tube indicate that the diaphram is not working.
I know after priming with effort that when I take it apart there is fuel in the metering cavity. When I pull the cord with everything hooked up and primed but without the throttle assembly so I can see the jet tube, no fuel is shooting out. If I know that a rebuild kit will remedy that, then I will order it.
Or if its the crank case is not putting enough pressure on the diaphram to pump the fuel. The gasket on the side sealing the crank case is not the best in the world.


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## geogrubb (Jul 28, 2006)

Not familiar with that carb, the Walbro site probably has tec info on it. I would suggest befor you order the kit to prime the carb full of carb cleaner and let it set for a day, then hook the return line to the carb inlet and prime it to circulate the carb cleaner through the carb a flush it through a few times, it might clear up. Have a good one. Geo


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## paulr44 (Oct 14, 2008)

Sir Thomas said:


> When I was testing the snap n primer bulb with a new filter and new line directly in a glass of fuel, I found that it doesn't have much draw power. The bulb is very slow in returning to shape with fuel in it. That may be part of the problem with purging the carb. Connected to the carb, the bulb is half full of fuel. If it did it's job, I'd think it should be full. Do they vary from one to another? This one was sold on ebay as A056013 Genuine Zama Snap in Primer Bulb MTD 791-683974B Ryobi 683974B by ICPower1. Which is a better snap in bulb? Good thing I didn't by in bulk.


If a primer is slow to return, whether integral or detached, it indicates a fuel flow problem to or within the carb. It can be as simple as a collapsed fuel line or clogged tank filter, or plugged up carb. screen. The primer simply applies a partial vacuum to the metering chamber, which in turn caused the metering diaphragm to move down thus opening the inlet needle, and that partial vacuum then draws fuel in from the pump side of the carb.

THIS may be as simple as a fuel line etc. restriction. I CAN'T IDENTIFY the first picture, it seems to be a small screen capture and doesn't open in it's own window as a JPG or BMP file.

A couple of things here: MOST external primer assemblies can be replaced by the Walbro 188-512 for but a few bucks.

A NUMBER of MTD 2-stroke carbs. ARE CHEAPER through MTD than Walbro aftermarket, so check that out. A NUMBER of the ones I've looked up are LESS THAN $30 so they're not worth rebuild attempts in my book.

P.S. Primer bulbs DO NOT usually fill up completely, but mostly. If not mostly, a problem may exist.


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## Sir Thomas (Dec 7, 2013)

paulr44 said:


> If a primer is slow to return, whether integral or detached, it indicates a fuel flow problem to or within the carb. It can be as simple as a collapsed fuel line or clogged tank filter, or plugged up carb. screen. The primer simply applies a partial vacuum to the metering chamber, which in turn caused the metering diaphragm to move down thus opening the inlet needle, and that partial vacuum then draws fuel in from the pump side of the carb.
> 
> THIS may be as simple as a fuel line etc. restriction. I CAN'T IDENTIFY the first picture, it seems to be a small screen capture and doesn't open in it's own window as a JPG or BMP file.
> 
> ...


I mentioned that I connected two new tubes to the snap in primer, dipped the in line without a filter directly into a glass of fuel. When i press the bulb bubbles go out the return line but the bulb is very slow to return to it's former shape. If I press it again it doesn't move at all.


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## paulr44 (Oct 14, 2008)

Then methinks the primer is NFG.


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## Sir Thomas (Dec 7, 2013)

Pictures of the Carb


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## paulr44 (Oct 14, 2008)

The tube in the 1st pic first post, and 3rd/4th pic last post is the nozzle, or feed tube. It MUSt be clear from top to bottom, so your answer is yes (you should be able to blow air or carb cleaner through it).

Of all your posts, you haven't posted the carburetor model number (such as WYA-23 or the like). The carb. you have DOES NOT have a brass main jet, such as a WYA-44, and in looking at the pics it appears to have a mixture screw in the side of the body. This mixture screw has a PLASTIC EPA cap over it to prevent tampering. If you were to run carb. cleaner through the jet area (nozzle etc) you risk ruining the o-ring on the mixture screw. I can't advocate altering the mixture screw setting, but in order to PROPERLY CLEAN the jet area out you'll have to remove the screw. BEFORE REMOVING the screw, turn it in slowly counting the turns. BEFORE returning the screw (besides cleaning the jet area which is where the screw seats), clean the tip of it and reinsert it to the previous turn count out from seated position.

P.S. Advice on WYA mixture screw service: using an alcohol based cleaner and after removing the plastic epa cap but BEFORE removing the screw, clean the screw hole, then spray a bit of WD40 in the hole to ease removal. BEFORE reinserting, spray the screw or hole with WD to ease reinsertion.


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## Sir Thomas (Dec 7, 2013)

paulr44 said:


> The tube in the 1st pic first post, and 3rd/4th pic last post is the nozzle, or feed tube. It MUSt be clear from top to bottom, so your answer is yes (you should be able to blow air or carb cleaner through it).
> 
> Of all your posts, you haven't posted the carburetor model number (such as WYA-23 or the like). The carb. you have DOES NOT have a brass main jet, such as a WYA-44, and in looking at the pics it appears to have a mixture screw in the side of the body. This mixture screw has a PLASTIC EPA cap over it to prevent tampering. If you were to run carb. cleaner through the jet area (nozzle etc) you risk ruining the o-ring on the mixture screw. I can't advocate altering the mixture screw setting, but in order to PROPERLY CLEAN the jet area out you'll have to remove the screw. BEFORE REMOVING the screw, turn it in slowly counting the turns. BEFORE returning the screw (besides cleaning the jet area which is where the screw seats), clean the tip of it and reinsert it to the previous turn count out from seated position.
> 
> P.S. Advice on WYA mixture screw service: using an alcohol based cleaner and after removing the plastic epa cap but BEFORE removing the screw, clean the screw hole, then spray a bit of WD40 in the hole to ease removal. BEFORE reinserting, spray the screw or hole with WD to ease reinsertion.


Walbro WYC 4-511


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## geogrubb (Jul 28, 2006)

Sir Thomas said:


> Walbro WYC 4-511


Here is the limk to the service manuals, I don't see WYC however. Have a good one. Geo
http://www.walbro.com/servicemanuals.aspx


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## paulr44 (Oct 14, 2008)

Walbro WYC-4. Go here for the IPL http://www.walbro.com/parts-service.aspx
Using wyc-4 as the part number, use the <Search by Walbro Part #> feature.

The main jet may be in the underside of the inlet needle/metering (black plastic) body, and may be non-serviceable as I don't see a part number for it.

In looking more closely at your pictures, the diaphragms appear to be NG. The main metering diaphragm (with the metal plate) appears collapsed, and the pump diaphragm (with the little flap valves) appears to have curled/deformed valves.

Try a kit: K10-WYC - can't go wrong for the price.


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## Sir Thomas (Dec 7, 2013)

Sir Thomas said:


> I mentioned that I connected two new tubes to the snap in primer, dipped the in line without a filter directly into a glass of fuel. When i press the bulb bubbles go out the return line but the bulb is very slow to return to it's former shape. If I press it again it doesn't move at all.


The Bulb WAS defective. I picked one up down at the Farm Supply place and it purges through the carburetor fine. Now work on the Carb itself.


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