STIHL 4-Mix Engines

[Merkava_4]

You guys got anything to say about them ?

I've been watching their string trimmers on YouTube and they seem very powerful.

The guys at LawnSite say the biggest problem with them is they don't like to run variable speed. It's either idle or full throttle. They say that's fine for brush clearing, but for edging along sidewalks, it's too much power and increases the chances of tearing up the turf.

[KE4AVB]

Of the 4 cycle handhelds they have been the most reliable ones mainly because they use 2 cycle fuel mix and can operate at various angles without oil starvation unlike those Ryobi and Troybilt 4 cycle units that I keep getting with destroyed engines due to lack of oiling.

I haven't used one enough to say much about using it at variable speeds long term just when I testing a repair but I haven't seen problems as I tend to part throttle around young trees and vinyl siding and underpinning. I do know several of my customers are using them. Some didn't even know their FS90s were 4 cycle until I listed adjusted valves on the repair order.

On the subject of adjustment they take a very narrow width feeler gauge as rocker arms are folded over the valve stems. Something on the order 7/64". or just their valve service kit that includes the gauge.

.004 IN and EX. Valve clearance

[RoyM]

Sorry, I am not a fan of 4 stroke handhelds. Having said that they are very torquey but they don't sound like they are running at the proper speed as I am used to my Echo's. Cutting at part throttle creates some problems. The fan is not turning fast enough to provide adequate cooling air so there is a risk of overheating. It is also hard on the clutch, clamping force is less. We saw a lot of burnt out clutches particularly on commercial units that saw heavy use because the operators were not running them at full speed. Same thing happens when the guard is removed and the line is allowed to extend beyond optimum length.