How to adjust valves on a stihl 4mix trimmer or blower 

Thanks for watching. Along with the video, the comment section can be a great resource to fill in the gaps that a video might have missed. Good luck with your machine.

No problem. Thanks for watching.

tartredarrow, that is a very good point about top dead center(TDC). If the valves move while wiggling the flywheel it is not TDC. The valves loosen faster than you'd think, but they're so tiny it's kind of expected. Machine runs well for a long time without adjustment, because there is an automatic compression release built into the cam gear. Once it gets difficult to start because compression release stops working it's past time to adjust the valves. You can adjust these valves by hand, no feeler gauge necessary. The amount of slop on these valves after running a hundred hours is very noticeable. Adjusting the slop out is plenty good enough for routine maintenance just don't over tighten them. He is also missing the seal that goes on the valve cover screw. Might be hard to get it to idle if it develops a vacuum leak. Keep up the great work and keep the videos coming.

@@1d1hamby If you adjust the slop out, that means the rocker is touching the valve. Which is too close. Or am I reading what you're saying, wrong?

hrdman2luv ,no, you are not reading it wrong. You can just adjust most of the slop out and not worry about having a feeler gauge. You also don't want it so tight that there is no slight wiggle in the rocker. A tenth of a millimeter isn't much but it still leaves a little play in the rocker. I'm just saying once you adjust it with a feeler gauge, it seems a waste of time to get real particular about adjusting it to exactly a tenth of a millimeter, when it'll keep running fine till it is several millimeters out of adjustment.

+michael orlowski No problem. Hope it helps. Thanks for watching!

Ok. Thanks for the tip!

Thanks for the suggestion. I don’t use this machine for daily trimming tasks anymore. It only gets intermittent use. I switched to a echo srm-2620 as my main trimmer. It’s a traditional 2-stroke design with no valves to adjust.

~ 100 hours really isn't that frequent to check and adjust valves for a simple air cooled screw type adjuster. I ride on-road motobikes and the mechanically old school ones require a valve check every 4,000 miles just to be safe - 100 hours on a yard tool at or near full throttle would be similar to cruising at 60 mph on my bike - 60 x 100 is 6,000, which is actually a more lenient check interval.

Tony's Lawn care Thanks. Not sure if the clearance is the same for that model. You may have to look that up. I know I use to use the same clearance on my BR 500.

Tony's Lawn Care No,they are NOT.

I agree! Great machines when new, but over time the valves are a pain. Mine seem to go out of adjustment once every couple of months, making it hard to start. It gets to be annoying after awhile.

If they are stretching that much you should really replace the valves.

It could be losing power for lots of reasons. I would start by changing the spark plug, air filter and fuel filter. Make sure the valves are adjusted if that model is a 4 mix engine and make sure the screen in the muffler is clean of carbon deposits. Here is a video I did about cleaning the muffler screen. How to clean a spark arrester on outdoor power equipment ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eBzLUZsdGcI.html

Carburador problem o bad ctanshatr seal.clean and adjust carb.first.

bruce cason did you find out how to rebuild that carb yet?

Try Steve’s small engine saloon. Other options are looking up the Zama part number of your carb.

Sorry, I’ve never taken a carb off a fs91r and I don’t own one to even go take a look at. Thanks for watching.

Yeah unfortunately when your filming videos there is always stuff you forget or overlook or don’t explain properly. Luckily everyone in the comments fill in the missing pieces. Thanks for watching and commenting.

bạn trộn nó bằng tỷ lệ 50: 1. 50 phần xăng đến 1 phần hai dầu you mix it using a 50:1 ratio. 50 parts gasoline to 1 part two stroke oil

@@LawnCareBusinessSuccess vậy 1 lít xăng chỉ cho 20 đên 30 mililit dầu. Loại dầu dùng cho động cơ 2 kỳ đung k? Cảm ơn.

That sounds about right, but make sure you read the label on the bottle of the oil you buy. Also you can only use two stroke oil as it is made to be mixed with gas. Điều đó nghe có vẻ đúng, nhưng hãy chắc chắn rằng bạn đọc nhãn trên chai dầu bạn mua. Ngoài ra, bạn chỉ có thể sử dụng dầu hai thì vì nó được pha trộn với khí.

Speak English

wcjcnc it’s called a brain fart while filming. Lol 😂. I agree the stihl 4 mix stuff gets very annoying over time. Thanks for watching.

Maybe I’m still in the honeymoon period at 3yrs but I’ve only had to adjust once and i love the power etc on my 4 mix equipment.

Because the bolt needs to be able to be adjusted as needed in the future. There is no perfect setting or adjustment as things change with use and metal expands and contract with heat. Thanks for watching.

@@LawnCareBusinessSuccess Blue loc-tite isn't permanent, I use it on bolts on my trailer and motorcycle, it's a soft glue that holds tight but can still be easily loosened with a wrench

Ok, thanks. You should film a video and show how to do it correctly then.