ryobi 725r fuel line routing

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  #1  
Old 08-19-08, 12:42 PM
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ryobi 725r fuel line routing

I replaced all fuel lines on my 725r but I mistakenly forgot the routing. I think I have it right but it will only run in the choke position. When you move the butterfly door towards the run position it dies. My routing is:
1.Tank line(with filter) to suction side of primer bulb
2.Blow side of primer bulb to bottom of carb with curved inlet pipe.
3.Top of carburator back to fuel tank (side with no filter)
I then removed carburator and clean out all ports, screens and little holes with compressed air and put it back on. Still will not run in anything but choke position. Any trouble shooting tips would be greatly appreciated.
 
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  #2  
Old 08-19-08, 01:02 PM
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The primer bulb should have two fittings, one short and one long.
Long fitting - fuel line goes to tank, not filter.
Short fitting - fuel line goes to fuel fitting on top of carburetor.
The other fuel line goes from the tank filter connection to carburetor bottom fuel fitting.
 
  #3  
Old 08-19-08, 01:52 PM
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Originally Posted by Airman View Post
The primer bulb should have two fittings, one short and one long.
Long fitting - fuel line goes to tank, not filter.
Short fitting - fuel line goes to fuel fitting on top of carburetor.
The other fuel line goes from the tank filter connection to carburetor bottom fuel fitting.
Man, you don't know how much help this is. I will check this later today. This may be the problem because I'm pretty certain I don't have it routed as per your description. Thank you.
 
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Old 08-20-08, 09:35 AM
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Ryobi fuel line routing

Originally Posted by Airman View Post
The primer bulb should have two fittings, one short and one long.
Long fitting - fuel line goes to tank, not filter.
Short fitting - fuel line goes to fuel fitting on top of carburetor.
The other fuel line goes from the tank filter connection to carburetor bottom fuel fitting.
OK, I rerouted according to your description but it still will only run in choke position. One thing I noticed that I'm not sure about is the position of the little one way check valve thing that goes on one of the lines. Can you tell me the direction of fuel flow so I can know that this valve is positioned correctly and does it go in the line coming off of the filter ? Thanks.
 
  #5  
Old 08-20-08, 01:31 PM
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The piece you are referring to as a check valve is just a connector. The hole in it should go all the way through.

I take it the trimmer worked before replacing fuel lines. After replacing fuel lines it would start but only run with choke engaged and dies when opening throttle.

My first inclination is adjusting the carburetor may get it running again. Did you install new diaphragms, etc. after opening the carburetor and blowing it out? If you did not, trying to adjust the carburetor may be a waste of time.

What is the brand and model number of the carburetor installed?
 
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Old 08-21-08, 06:00 AM
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Originally Posted by Airman View Post
The piece you are referring to as a check valve is just a connector. The hole in it should go all the way through.

I take it the trimmer worked before replacing fuel lines. After replacing fuel lines it would start but only run with choke engaged and dies when opening throttle.

My first inclination is adjusting the carburetor may get it running again. Did you install new diaphragms, etc. after opening the carburetor and blowing it out? If you did not, trying to adjust the carburetor may be a waste of time.

What is the brand and model number of the carburetor installed?
The trimmer quit running and cracked fuel lines and air in lines was the first thing I noticed. I of course assumed this was the problem but now think other things must be going on as well. It will run in choke position but throttling it has little to no effect on engine speed. If you then move the lever towards run just a little (allowing more air to enter carb) it dies fairly quick but you can get increased engine speed by throttling it quickly just before it dies. I dissassembled the carb last night to just check it again. I feel without a shadow of a doubt there are no abstructions. I have followed the direction of flow through the carb and know all pathways are unabstructed. I sprayed carb cleaner an blew out with compressed air. Diaphram doesn't seem to have a hole in it at least as far as I can visually see. I guess the next step is to put a carb kit on it and see what happens. I have also check tightness of all screws and bolts around the engine and carb. I can also continuesly push primer bulb and eventually see gas come out of carb. No doubt its getting fuel. You requested the brand and model # of carburator. Is this marked on the carb itself ? Thanks.
 
  #7  
Old 08-21-08, 06:39 AM
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Yes, the manufacturer name and model number are on the carburetor.
Most likely it is a Walbro. Model number most likely will be WT followed by two or three numbers. Get you carburetor kit based on the Walbro model number not the Ryobi number.


Download “Diaphragm Carburetors” manual from this site:
http://wem.walbro.com/distributors/servicemanuals/
 
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Old 08-21-08, 06:03 PM
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Originally Posted by Airman View Post
Yes, the manufacturer name and model number are on the carburetor.
Most likely it is a Walbro. Model number most likely will be WT followed by two or three numbers. Get you carburetor kit based on the Walbro model number not the Ryobi number.


Download “Diaphragm Carburetors” manual from this site:
http://wem.walbro.com/distributors/servicemanuals/
OK, I've inspected the carb and the only writing that I see on it is 4 sets of numbers
P17
1YA
C1U
126H
I don't see a manufacturing brand on the carb itself. I looked at each of the carbs on the link you provided and none seemed to be exactly like mine. I purchased a carb kit that my local repair shop said would fit. It is a Walbro K10-WAT Kit. To my utter frustration I've just learned that none of the gaskets/diaphram fits my carb.
 
  #9  
Old 08-21-08, 07:48 PM
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Zama Carburetor

Your carburetor is a Zama and the name is usually cast into the fuel pump cover. The body type according to the numbers you found is a C1U and the model is P17. The rebuild kit is a Zama RB-98

You can find some information about Zama carburetors in this Tech guide from their website.

http://www.zamacarb.com/pdfs/TechGuide_2007.pdf

Best of luck...
 
  #10  
Old 08-22-08, 06:39 AM
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Sorry about throwing you off with the Walbro reference. Every IPL I looked at showed a Walbro.

An odd shaped welch plug 0005004 is included in the RB-98 kit that requires a special tool to install. You may not need to remove the plug. Review “Welch Plug” in the Zama Technical Guide to determine if it will require removal. If plug is removed incorrectly, the carburetor may be damaged. To install the plug, if removed, fabricate a tool from a piece of metal.

http://www.zamacarb.com/prod_lookup.cfm


Good luck
 
  #11  
Old 06-26-11, 01:17 PM
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Simple rule for fuel line routing on 2 cycle engines

here is a simple reference to all fuel line routings with detached primer pump, (not mounted on carb) The line from the fuel filter in the tank goes to the "iin" side of the carb. this is not marked. so try it and see below. the "out" port of the carb goes to the suction side of the primer ball, the discharge side of the primer ball goes to the overflow line back to the tank. please note, if the in and out lines to the carb are reversed, the primer ball will return slowly when pushed. if properly installed the primer ball will return quickly when pushed.
Please note, the fuel is sucked through the carb, not pushed through it[.I am trying to figure out how to attach a sketch, but cant see how it is done.
 
  #12  
Old 05-02-12, 05:53 PM
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Just another note for fuel line routing!

The "return line" from the Primer bulb is supposed to feed back in to the fuel tank, and that entry point is difficult to find, and even harder to feed the line in since it's a "friction fit". The port is nothing but a hole in the tank, just inboard of the filter line port. If you cut the line on a rather sharp angle, you can feed the pointed end in through the hole, and then from the inside of the tank, you can pinch, and pull the line fully into the tank with a small set of needle nose pliers. You only need to get it in a little past the trailing edge of your diagonal cut such that the "hole" in the tank firmly grips the entire "OD" of the return line.
 
  #13  
Old 05-03-12, 08:29 AM
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If you go to this site and look on the right side their is a video on how to test for correct line routing. I use it all the time because I have CRS
Ryobi Trimmer Parts : eReplacementParts.com
 
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