Ryobi 725r .31 cc carb primer stuck weedeater problems


Old 07-02-04, 08:30 PM
Visiting Guest
Posts: n/a
Ryobi 725r .31 cc carb primer stuck weedeater problems

After reading and printing out several suggestions on dealing with the Ryobi, I still need help.

My Ryobi 725r has always worked just fine until this season, when it was run poorly and die if too much gas was triggered. Well, today, it would not start at all. I removed and cleaned the carb to include all the holes and screen, I cleaned the muffler and ensure there is no blockage and cleaned my plug which was VERY oily. I checked my fuel filter and hoses which are brown, but not blocked.

Now that I've put the whole thing back together, the primer bulb stays 'stuck in' when i attempt to pump it. The machine will run on carb cleaner and then die, but for whatever reason it's not getting gas.

Any suggestions? I've not read what to do about a stuck primer bulb.


Sponsored Links
Old 07-02-04, 08:47 PM
Visiting Guest
Posts: n/a

it sounds like you need to verify fuel will pass thru the filter.
i've had this problem before and that was the problem.
Old 07-02-04, 09:53 PM
Visiting Guest
Posts: n/a
Thanks for the tip... the fuel filter looks clean and white and is affixed to the inside of the fuel tank. Exactly how does one get that thing out LOL!
I bet your right tho!!!
Old 07-02-04, 10:49 PM
Visiting Guest
Posts: n/a
hello again,

i always use carb and choke cleaner.
i disconnect the fuel line from the carb and spray carb cleaner in the fuel line
toward the fuel filter let it sit a minute, then use compressed air to back flush the fuel line. repeat til air flows easily. as to how to remove the filter i believe the fuel line wall thickness holds the filter in place, do'nt hold me to this though. check with your local repair shop for advise. i hope this helps.

Old 07-07-04, 12:17 PM
Visiting Guest
Posts: n/a
If you remove the plastic housing that holds the bulb, you should be able to remove one of the fuel lines from the back of the bulb. If you remove a line and the bulb pops back into place, then the line is causing the problem. If not, you probably need to replace the bulb. About 5-8 bucks depending on where you buy it from. I replace mine every year. As for removing the fuel filter, it comes out of the gas filler hole after disconnecting the hose from the other end. I doubt you'll be able to to put it back in though since you'll need a longer piece to be able to put the filter back on. (And then reposition the filter in the tank properly.) Also check the routing of the fuel lines. One side feeds fuel to the carb and the other side returns the fuel to the tank. Screw them up and the unit will not run for very long. Also if this model is the 4 cycle model, it is very sensitive to the mixture adjustment, which seems to get out of adjustment due to the vibration.
Old 07-08-04, 09:19 AM
Visiting Guest
Posts: n/a
Runs for 3 seconds....

Thanks for your notes. Here's where we're at. After soaking the whole system with carb cleaner, the bulb no longer sticks in... Now, the unit will fire up normally using the typical starting procedure of first priming, then A choke then B choke. As you indicated, the problem is the machine will only run a few seconds and die.

I suppose it could be the fuel filter. When I pull the line off the fuel filter (which is mounted in the tank) the filter stays put in the tank. Part of it comes out the bottom of the tank ever so slightly.

Suppose it is a problem with the lines. I don't think I screwed that up, although anything is possible. How would I confirm the proper routing of the lines? I can't find this on the net and the machine isn't sold near me.

And I still don't know how those adjustment screws play a roll in this....it is a 2 cycle .31cc motor.

Thanks for your attention,

Old 07-08-04, 11:04 AM
Visiting Guest
Posts: n/a
You should have 3 adjustment screws, 2 side by side and a 3rd that sets your idle speed, the 2 side by side should have plasic caps on them? If so did you remove these to soak the carb? Any info I have gathered for initial settings has differed greatly between manufactures even when using the same carb type. And the Ryobi site is down at the moment so I am refering to my manual for my 790R but should get you going. Idle setting, this will be the screw off on it own that when turned in(clockwise) opens your throttle plate. Screw this in until it just comes in contact with the plate that opens the throttle, then continue 2 turns for walbro 1 1/2 turns for zama.
If the plastic caps are still intact on your mixture screws and have not been deformed or turned past the stops, set them clockwise to the stop. If they are deformed and or have been turned past the stops, you will need to remove them to find out how many turns out they are from seated. My manual says the initial "high speed mixture" is set at 1 1/4 turns out from seated. It does not mention a setting for idle mixture other than out to the stop, but I would think 1 turn out should get you going. If this gets it going, turn the low needle in until the fastest idle is achieved then back it out 1/8 of a turn. Squeeze the trigger and if the engine falters continue backing the idle mixture screw out 1/16 of a turn at a time until it accelerates rapidly.
As for the fuel lines and filter, if you remove supply line at the carb have fuel in the tank and the end of the fuel line is below the level in the tank, you should have fuel flowing free.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title: