Some use a real oil sump, but with some form of movable pickup such that they can be run in various angles without much trouble. Robin (also used in Makita) and Honda versions are like this. Others still use an oil mix with no sump, burn the oil, and are fully lubricated any time they are running just like two-strokes. Stihl 4-Max and Shindaiwa C4 are like this. Most of the posts I've seen of people with trouble actually relates to valve adjustments. I have a good friend with the Robin BH2500 and it is great, and no troubles after two years.

I have several Ryobi 4 stroke trimmers that I have used for years. They are reliable and mostly trouble free. They can be run at any angle or even inverted with no problems. They are powerful too.

I bought a Cub Cadet 4-cycle at the beginning of the season from Home Depot and had the same concern. A friend of mine told there is not problem running these at an angle becuase of the overhead valve set up in engine. The trimmer has worked great especially the starting which is just prime and pull the starter. THe 4-cycle is a lot quieter and burns much less fuel then my old RYOBI 2-cycle. I use the edger attachment with mine.

The '4-Mix' engine is fascinating, and I'd love to see a larger one on a mower. Seems like it would have most of the benefits of a 2-cycle, even the smell.

I have a 2 year old Honda 4 stroke trimmer. It has been much more reliable for me than the 2 stroke Echo it replaced. It is quiet and powerful.

I read from some forum that Makita EM4251 4 cycle trimmer being a rebadge Robin, have cast iron lining. Is that true? What kind of cylinger lineing does Honda 4 cycles engine has if any?
THanks

Makitas definitely are rebadged Hondas. I know that's true. I do not know the liner material used on their cylinders, though. The website doesn't say. I have use the BH2500 and it is a light, compact trimmer that works extremely well.

You mean Robins not Hondas!! Right? I would like to get the 33cc Robin 4 cycle, just can't find a dealer in San Francisco area.

Dammit! Yes, I meant Robins. Sorry. Yeah, Robin dealers seem to be few and far between. There actually seem to be more Makita dealers. BTW, I noticed that Home Depot, of all places, now carries the Makita 4-cycle handheld blower (same as the Robin 2500 blower). I would not have expected that!

Thanks for the information. You try the Makita/Robin in different position and is OK?
Have a nice day

Yes, I've tried it in various orientations and it works fine. It must have some sort of weighted flexible oil pickup in it's tiny sump, so that the end of the pickup always follows the oil wherever gravity takes them. It's been a while so I can't recall for sure, but there may have been some limit of travel - like you aren't supposed to turn it fully upside down or something. But you should download the manual from the Makita site just to check me on that. But if there is a limit, it's nothing that you would ever approach during use anyway.

Really appreciate your help
Thanks

have and echo, 9 years old...never a problem...

Some sytems were just meant to be 2 stroke, I think trimmers are one of them. 2 Stroke is not a bad thing. The problem today is that people associate it with the pollution of Diesel and that's just not true.

I have a Makita 2 stroke that is 12 years old now and has seen conditions that no trimmer should ever see. I got it on a closeout from a big chain store going out of business. Very impressive power and reliability. only about 2 years ago did i realize there was supposed to be an air filter that it never had and am not sure why. I used to blaze a trail through weeds over 12 feet tall to the Ohio river for me to go fishing there. Was about 200 feet long and 10-12 feet wide. Took 45 minutes each time to do. My old McCollough took over 3 hours and bit the dust after 1 season. You get what you buy and usually you pay for it.