# Ryobi 15" String Trimmer -- Starting/Running Troubles



## Tomcat (May 12, 2005)

Over the last couple years, I have had trouble keeping my Ryobi string trimmer running after starting.

I follow the starting instructions -- close the choke, when the engine tries to start, open the choke half way, after running for a short time, open the choke. I was able to get the trimmer started without much difficulty. However, when I would open the choke all the way, the engine would cut out. This would happen until the engine ran for several minutes. Once the engine would run for several minutes, it ran fine.

I have checked the filters, lines and tank for dirt, cracks or blockages. I drain the fuel at the end of every season and always use fresh gas/oil mixture. I have used carb cleaner on the carburator and fuel lines.

This season, I can't even get the trimmer started!

Any ideas? Suggestions or advice is greatly appreciated.

Thanx--

Tomcat


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## bugman (Aug 12, 2004)

well one thing is to check the spark, then compression, and if those are good, it most likely needs a carb rebuild


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## hankster (Jan 1, 1998)

Open up both needles on the carb about 1/2 turn and see if it'll run. The engine dying when you open the choke is a sign the engine is too lean.


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## Tomcat (May 12, 2005)

Hankster / Forum Members --

After my initial post, and thinking about it, I agree with Hankster -- it seems to be running lean. I think air is leaking in (bypassing) the proper channel.

After filling the tank and letting the trimmer set, the fuel leaked out. There must be a leak in a line or the bulb. The bulb is not filling with fuel. It doesn't have the vacuum to draw the fuel. I guess it is considered an in-line bulb -- depress the bulb, when the bulb releases, it draws fuel into bulb, next bulb depression forces fuel into the carb.

This may be a good sign because perhaps the carb is okay. The trouble has been isolating the leak. Everything seems okay. Based on the fuel drain, bulb not filling, and apparently running lean, a leak seems likely.

Any suggestions isolating the leak or checking for other possiblilities?

Thanx--

Tomcat


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## hankster (Jan 1, 1998)

Actually the purge bulb on a Ryobi is a "sucker". The line from the filter in tank should go to the inlet side of the carb, then from the carb to the bulb and then back to the tank. If the lines are hooked up wrong then it could cause the bulb not to fill and cause a lean running condition (if you can even get it started). As for the leaking.... it could be leaking out of the vent in the tank cap?


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## Tomcat (May 12, 2005)

I have never changed the lines. They are hooked up the same as when purchased.

The tank cap is located on the top of the tank. I had the trimmer setting upright, so it didn't leak from the tank cap.

Any other ideas?


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## hankster (Jan 1, 1998)

You'll just have to clean everything up and let it set so you can find where it is leaking from.


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## hankster (Jan 1, 1998)

Here is a picture of how the lines should be. If they are not routed like this they are wrong.

http://www.hobbytalk.com/bbs1/attachment.php?attachmentid=18359


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## quemado (May 25, 2005)

I have a Ryobi 775r trimmer and have similiar issues with it. It starts ok, idles rough for a while, and begin to run a little bit smoother. I have the gas fully depressed but it never seems to get to full rev's. Once I begin to edge, it begins to bog down. It never reaches full power. I bought a new carbuerator, installed it, and guess what, nothing changed. DOes anyone have any ideas? I guess I could change the spark plug but I don't think that that is the issue. If this were a car engine, I'd say that the valves were bad, losing pressure....


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## hankster (Jan 1, 1998)

I would first try and adjust the carb to see if you can get it to run properly. If that doesn't help remove the muffler and see if the screen is plugged.


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## quemado (May 25, 2005)

Hhhhmmm, sounds like a plan. I will report on my findings. Thanks Hankster.


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## coyoteosf (Jul 26, 2006)

Hi guys,
Is the carb inlet the bottom fuel inlet or the one on top of the carb?

Thanks!


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## hankster (Jan 1, 1998)

Pictures here http://www.hobbytalk.com/bbs1/showthread.php?t=147204


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## coyoteosf (Jul 26, 2006)

Thanks Hankster!


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