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Ryobi string trimmer wont start


jl66redcpe's Avatar
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05-07-09, 04:21 AM   #1  
Ryobi string trimmer wont start

I have a Ryobi string trimmer in the shop that just wont start. It is a CS30 Model 30000. I have spark at the wire end and also the plug is firing. I removed the a/f cover and with (for lack of a better description) a tiny turkey baster added gas to the venturi. Will not even attempt to fire. The spark plug was wet so it seems gas is getting to the cylinder. Used the turkey baster to pour some fuel down the spark plug hole -- nothing. The engine seems to have real good compression. I was going to try and clean out the carb however Ryobi tech told me there is no rebuild kit for this carb. It is a throw away item. All help regarding next steps is appreciated on this one.

 
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05-07-09, 06:07 AM   #2  
My guess is that the carburetor is dumping fuel into the crankcase. You need to flush out the crankcase of the excessive fuel and recondition the carburetor with a new rebuild kit. Remove the spark plug, move the plug wire out of the way, make sure the kill switch is activated so you get no power to the wire, remove the carburetor, spray a small amount of carb/choke cleaner into the intake port, cover the plug hole with a paper towel, pull the engine over six, or so times, replace the paper towel with a new towel, spray some more carb/choke cleaner in the port, pull it over another six times. Repeat this process until there is no indication of fuel on the paper towel and you are sure there is no more fluid in the crankcase (including and especially carb/choke cleaner as there is no lubrication in it and you don't want to seize the engine after you have reassembled the machine) . Post back with the make, model and serial numbers of your carburetor (found on the carb). I'm certain there is a rebuild kit for it. It should be either a Zama or Walbro carb and you can get a kit at most small engine shops for the carb that carry such parts...not a Ryobi kit.

 
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05-07-09, 02:19 PM   #3  
As it turns out, I also had a McCulloch trimmer in with the same problem. I decided to try out some of the archived procedures I found on the McCulloch and if they worked move on to the Ryobi. They both have Zama carbs on them. I removed the plastic caps (without breaking them), removed the high and low speed jets and the spacer and sprayed carb cleaner in the holes. I then blew them out with about 20-25 lbs of air. I next squirted carb cleaner in the venturi area and also tried to blow some in the carb inlet. I next lightly blew air in the carb inlet. I put everything back together including the plastic caps, primed it, and it started after a couple pulls. I was pleasantly surprised. Well, now it is on to the Ryobi. Any comments pro or con on the procedure would be appreciated.

 
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05-07-09, 09:52 PM   #4  
Sounds like you did what you need to do, and I'd do it again on the Ryobi and hope for success.


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05-08-09, 09:18 AM   #5  
Well, I did the same procedure to the Ryobi and it would not start. Any sugestions on what i can check next. I have tried to remove the air box and the carb and it wont budge. How much do I have ot remove to check the flywheel key.

 
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05-08-09, 10:14 AM   #6  
If your flywheel retaining nut is tight there isn't anything on a trimmer to shear the flywheel key = no sudden stop at the load end. The coil drive spring absorbs most of that.

I would suggest dumping all the gas out of the tank and pull the plug. Then with full throttle and the ignition off, plug wired tied out of the way, spin it over about fifteen or so times to completely purge the gas out of it.

Then add a teaspoon of gas mix directly into the cylinder, new plug, no choke, half throttle. See if it will start for you. If it does, put it all back together and run it off the tank.

 
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05-08-09, 12:04 PM   #7  
thanks marbobj I will try it

 
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05-08-09, 03:25 PM   #8  
Well, I took a compression test on the unit and it only produced 60PSI. This was after pulling both 3 and 5 times. Looks like I found the problem. I usually do this test first on any 2 cycle but of course not this time. Looks like this one goes to the scrap pile.

 
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05-08-09, 05:15 PM   #9  
Yep, you found it. 60 lbs won't start that little jewel. Sometimes you can get by with a little less compression on a two stroke mower with the blade impetus on it, but a trimmer or chain saw will do nothing but build your bicep.

 
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05-10-09, 05:21 PM   #10  
I went ahead and removed the muffler to look at the piston, ring and cylinder. The piston was scored and the ring appeared frozen in the groove. Cylinder looked ok from what I could see. I was surprised that the muffler screen was completely clean -- not even a spec of oil or dirt. Makes me think that this unit was running lean or with not enough oil in the mix. Do you think this is worth repairing. What might the approximate cost for a new piston, ring and crankcase gasket be. I tried soaking the ring with PB Blaster and then Sea Foam however it would not free up.

 
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05-10-09, 07:01 PM   #11  
If the piston is shot the cylinder on the side of the piston scoring is likely done as well. I imagine you'd have seventy dollars in the piston, barrel, ring, and crank seals.

 
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