Ryobi Short running

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  #1  
Old 12-27-06, 12:13 AM
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Ryobi Short running

Hi,
New member hoping to get some help with a 2-stroke problem.

I have two Scorpions. One is for spares now that it's starter rope is pulled off The second needed new fuel hoses, had been dormant for some time. I replaced the hoses, priming bulb and fuel filter with new items. Fine. Starts first go, but it ran for only a minute. I re-primed, started again. Stopped again. So I thought it must be the carb. Must be getting spark, as it ran when freshly primed.

I pulled the carb from the spare machine, which was running fine until the starter cord ripped, and installed it on the first machine. Same problem... runs (blowing a little white smoke) but stops as soon as the priming fuel has burnt off. I can see that fuel has flowed into the main fuel line, there aren't any ~apparent~ air leaks... plug was removed, cleaned and replaced to no avail.

I throw myself on the mercy of the collective wisdom of this board. Why is the engine failing with two good carbies? What is my next port of call in troubleshooting?

Cheers,
Rob from downunder.
 
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  #2  
Old 12-27-06, 06:54 AM
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I'm not sure what you have, either a Scorpion stern drive boat or Scorpion agricultural sprayer? Since you indicate that it has sat dormant for some time, it is likely that your fuel oil mixture has dried and gummed up the passages in the carburetor. My father has a Mantis tiller which he failed to run dry at last use and despite my best efforts at soaking the carb in cleaning solution, I finally had to just purchase a new carburetor. This may be your fix, if you cannot clean out all of the passages in your carb. Best of luck.
 
  #3  
Old 12-27-06, 02:14 PM
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Oh sorry, I didn't know Ryobi made more than one product called Scorpion. It's a Grass Scorpion line trimmer.

The strange thing (to me) is that the problem is the same for both carbs. The one that has sat for ages and the one that came out of my freshly broken trimmer. They both do exactly the same thing, run only on the primed fuel. Might try some carb cleaner as a next step... Step after that will be a new trimmer, methinks. The edges around the fence are knee-high.
 
  #4  
Old 12-29-06, 07:50 AM
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You will want to remove the muffler and have a look at the condition of the piston and cylinder. I'm going to guess that it is toast. In other words, the engine is not producing enough vacuum to draw in any fuel from the carb.
 
  #5  
Old 12-30-06, 12:53 AM
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Cheers Puey61, I'll check that out. Might need to just repair the pull start on my trimmer, and move over the best parts from both machines, as adjusting the carby on the "spare" left it running for no more than about a minute. New ones are A$169 down here, so if I can, I'll save that... as the vacuum cleaner just went out in an interesting display of sparks today... what a week for appliances!
 
  #6  
Old 12-31-06, 11:51 PM
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Angry ryobi grass scorpion

Hi, I am another frustrated backyard DIY repairman from Downunder. I couldnt start the Ryobi Grass Scorpion trimmer some weeks back so replaced the spark plug but still no luck, so today I disassembled the line trimmer and cleaned all parts, reassembled leaving the muffler off and sprayed WD40 (carby wet start) into the spark plug housing, gave it a rip and it started for a few seconds. Pulled the fuel line off and fuel spilled through so I assumed this was ok. I dropped a small amount of fuel into the spark plug housing and it started again but only briefly. I assume fuel is not getting to the housing or there is no vacuum to draw in any fuel from the carb.

Any ideas what to do next? How do you check the vacuum and if fuel is getting through?
 
  #7  
Old 01-01-07, 12:30 PM
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Smile

Check the compression with a compression guage,it should be 90# or better for it to run right,also check the cylinder bolts I have found that they will come loose and cause a air leak,hope this helps.

Jerry
 
  #8  
Old 01-02-07, 10:59 AM
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A visual of the piston and cylinder will tell you alot. If they are questionable and you aren't familiar with exactly how they should look then you need to consult a professional. If they, on the other hand, are OK then you need to soak and serivce the carburetor.
 
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