How exactly do you tune a 4mix?

[SawAddictedFarmer]

Normal usage, they go out of spec, and cause running issues, and harder starting.

What oil are you running? Our fs110 has had 10 years of abuse and they were only just out of spec. Almost it's entire life it's been 40:1 or 32:1.

 

[hacskaroly]

What was the reason you had to adjust the valves?

They are easy to check and quick to adjust as part of (at least) annual maintenance. I have had my FS 91 for four years and it is getting hard to start but runs great when it finally does...I have not done anything to it yet besides add fuel and string...so its about time to check the filters, spark plug and valve lash.

 

[lilspenny]

From my experience with my fs131r, br800x, and fs100rx the valves have needed very little adjustment. It's not as big of a deal as some naysayers think. Once every year or two and it takes 10 minutes at most. Twenty years on my fs100rx and even then they didn't really need it. I love the 4-mix low end torque for string trimmers. Not a big deal with blowers.

 

[lilspenny]

What oil are you running? Our fs110 has had 10 years of abuse and they were only just out of spec. Almost it's entire life it's been 40:1 or 32:1.

I have found a few oils that I really like. These are for 4-mix engines.... Saber at 64:1, Motul 710 2t at 50:1, and Motorex Cross Power 2t at 50:1. I like Maxima K2 at 50:1 but think 60:1 would be better. One oil, one ratio for all types including chainsaws? Saber at 50:1 with good quality 93 octane ethanol free. I've been testing 10 oils and those are top quality insofar as lubrication, cleanliness, and runability.

 

[bogieboy]

What oil are you running? Our fs110 has had 10 years of abuse and they were only just out of spec. Almost it's entire life it's been 40:1 or 32:1.

I use stihl hp ultra at 40:1... also, i am a certified stihl tech, so out of spec to me is different than most peoples idea of out of spec.....

 

[EFSM]

I see 4 mix’s every year that barely crank due to extremely excessive valve lash. I don’t know how someone can run them till they have .020” lash

 

[bogieboy]

I see 4 mix’s every year that barely crank due to extremely excessive valve lash. I don’t know how someone can run them till they have .020” lash

Same.... as soon as that feeler slips freely in, it gets adjusted on mine, same goes with any that i work on... if i touch it, its getting valves adjusted.... period...

 

[lilspenny]

Same.... as soon as that feeler slips freely in, it gets adjusted on mine, same goes with any that i work on... if i touch it, its getting valves adjusted.... period...

Are you finding more tight or loose valves. Another question... Are you seeing any evidence of ash buildup from using "low ash" oils such as Saber instead of Stihl Ultra?

 

[EFSM]

Are you finding more tight or loose valves. Another question... Are you seeing any evidence of ash buildup from using "low ash" oils such as Saber instead of Stihl Ultra?

5-10 years ago, I saw more tight valves, almost like they had a batch of engines that pounded the valve seats into the head or had higher wear valves/seats. Nowadays they’re mostly loose.