I need to know the fuel-oil ratio/mix for my Ryobi 700r String grass trimmer.

Are you sure about the model number? I see several 30CC engine string trimmers by Ryobi. Two are the Ryobi RY30040B (SS30) and a RY30544 (SS30).

For both of these models, mix a high quality 2-cycle engine oil at 2.6 oz. per gallon of gasoline to pour into the gas tank. This ratio is used in several other Ryobi string trimmer models. Many Ryobi product manuals are available here: https://www.ryobitools.com/power-tools/support/manuals . Most Ryobi gas powered and 40V battery-powered tools will have a model number that starts with RY. The 18 V battery powered models often start with a P.

I hope this helps. If you add a comment with the actual model number, I may be able to provide more information.

Cindy Wells

Hi marius65..
Use the normal mixture for 2 cycle engines
50 to 1 mixture...1 pint of 2 cycle oil to 6 gallons of gasoline
Please rate me
Bud

Fuel/Oil Mix ratio is 40:1. That is 3.2 oz oil per gallon of gas, or 1.6 ounces of oil/ half gallon of gas. I highly recommend using a good synthetic 2 stroke oil. Many benefits there.

Hi and wel;come to FixYa, I am Kelly.
The part you need is item 9 on most parts lists:

Your problem is caused by either drive shaft failure or.. clutch failure. Most of the time the drive shaft fails before the clutch.

The manual is here:
http://www.mymowerparts.com/pdf/Ryobi_String_Trimmers_Blowers_Tillers/700r.pdf

Shaft is PN 682064 or 753-04280

Sears parts direct has the shaft as item 10 this link:
http://www.searspartsdirect.com/partsdirect/part-model/Ryobi-Parts/Grass-trimmer-weed-wacker-Parts/Model-700R/0909/1503820/10060718/00002?blt=06&prst=0&shdMod=700R

Detailed view:
http://www.searspartsdirect.com/partsdirect/part-number/Ryobi-Parts/Grass-trimmer-weed-wacker-Parts/753-04280/0071/247/Model-700R/0909/1503820?keySuffixId=NA&productTypeId=x&searchModelNumber=700R&subCompDesc=Boom%20and%20trimmer&brandDesc=RYOBI&modelDesc=TRIMMER&pathTaken=partSearch&blt=11

Lower price here:
http://www.mowpart.com/p661995/Flex,-Shaft-(Rpls-682064)/product_info.html

Average price ($32.50)

Thanks for choosing FixYa,
Kelly

Hi, it has to be a 2 stroke oil for air cooled engines. Mix with regular gas at a ratio off 25 to 1. Regards Phil.

Check the fuel/oil mix ratio you are using. Some Ryobis use a 32:1 mix and some use a 40:1 mix. There isn't much difference there. To be on the safe side, if you machine is possibly running or tuned a little "lean" I would start off with about 4 oz/gallon oil to gas mix. Use synthetic 2-stroke oil also. Your machine will perform much better.

33:1 to 40:1 is typical on about 95% of all line trimmers. I own (2) 700r's and one is 32:1 and the other is 40:1, you won't go wrong at 35:1 with current 2-cycle oil. Suggest using low-smoke brands.

Mixture is typically 40 or 50 to 1, gas to oil. The exact mix should be stamped on the gas cap.

50:1

Ryobi trimmers I have had use a 32:1 oil mix. Just pick up a little bottle of Ryobi 2-cycle oil and read it to see that it will give a 32:1 mix in a gallon of gas. Pour it into a gallon of gas, and maybe a little fuel stabilizer too, shake it up and you should be good for the season.