Stihl 4 mix engine valve adjustment

16 years ago

I went to my stihl dealer today to get a spark plug for my ms250 chainsaw and one for my BR550 backpack blower. I bought some of the decarbon stuff they sell as well. I asked him if they had any special tools to adjust the valves on the 4 mix engine. He told me Stihl is updating the maintainence procedures for the 4 mix. When they first came out, they didn't know what to expect so they said to adjust the valves at 139 hours. Now that they have been out for a while, he told me that Stihl now suggest not to adjust the valves. Anyone else hear this from their dealer?

Sort by:Oldest

Comments (9)

cranheim
16 years ago
That certainly is a twist to what STIHL has said for the last few years. I have a BR600 with about 150 hrs on it. I purchased the valve adjustment kit which included the special feeler gage. When I went through the adjustment procedure, I found the valve lash was too loose. I cannot tell you how loose, because the special gage will only fit in the channel shaped rocker arm, and is made with the correct clearance. After tightening the valve lash, the blower had more power. My dealer confirmed they had the same result after the first valve adjustment. I sure hope someone out there can give us the real skinny on what this is all about. Charles Ranheim
den69rs96
Original Author
16 years ago
I found that ironic as well. I have somewhere around 50-75 hours on mine so I don't need to think about valve adjustments for another few years. I do want to perform the decarbon process once my regular stihl non syth oil runs out. Then I'll use the synthetic oil for that point on. Overall, I'm still impressed with the power and reliability of my Stihl products.
Related Discussions
stihl br600 blower maintenance
Q
Comments (2)
I used STIHL De-Carbonizer p/n 0781-313-8018. Charles Ranheim
...See More
Stihl MS-250 chainsaw engine bogging down
Q
Comments (15)
I think the big mistake here is everybody is focused on the carb. Take the Pull Start cover off(where air enter to cool the cylinder) and likely you find area around the flywheel fan and spark coil packed with oily/wet saw dust. This dust can cause just enough resistance that the motor will run at low speeds but fail to accelerate(bog down). If you coax it to high speed it basically runs without spark from heat(dieseling). Clean fan,coil and cylinder fins regularly to avoid this and other problems(overheating). This post is late but may help somebody.
...See More
stihl 4mix engine
Q
Comments (2)
Thanks for the reply, its put my mind at rest, it does it at at any revs some times not only at full revs but still ticks over and runs fine without cutting out.
...See More
stihl br600 blower valve adjustment
Q
Comments (3)
A STIHL dealer was nice enough to sell me a Valve Setting Kit that contained a special feeler gage with a narrow tip, a valve cover gasket, and a small washer. There are no instructions with the kit. The kit was part number 4282 007 1001 A. I did not open the sealed plastic bag with these parts. I will wait until I need to use it. I have not tried to measure the thickness of the gage because it is still sealed in the bag. I thought I read somewhere it should be .010". I wonder if all the STIHL 4-Mix engines have the same valve clearence. Does anyone know for sure? I also have a KM110R STIHL Power head with a 4-Mix engine. However, I put much less time on that than I do on my BR600. Thanks for your interest and comments. Charles Ranheim
...See More
dave_mn
16 years ago
To heck with the adjustment...how the hell do I know when I have 139 hours on it?
cranheim
16 years ago
I wonder if the dealer who said STIHL was going to discontinue the valve adjustment requirement just made that up so more people will buy the 4 Mix engine machines. This valve adjusting and de-coking requirement turned me off for a while. However, now that I have done both procedures, it is no big deal. I am willing to live with the maintenance requirement because I am so satisfied with the performance of my BR600. I think using the STIHL Ultra full synthetic oil reduces the wear and potential carbon problem. There has to be some STIHL dealers who look at this forum who could shed some light on this subject. Charles Ranheim
cranheim
16 years ago
I asked my STIHL Dealer about the possibility that the valve adjustment requirement on the 4-mix engines may go away. He never heard of such a thing. His experience shows it is necessary to adjust the valves on the BR600 after about 150 hours. He said it may not be necessary to do it every 150hrs. It is the initial adjustment he feels should be done. In my case, the engine ran better after the initial adjustment. Charles Ranheim
den69rs96
Original Author
16 years ago
Cool thanks. I think I'll do it the first time just to be safe. Charles, how much was the special feeler gauge and did it come with any special instructions? I've only adjusted valves on a small block chevy, so adjusting valves on a stihl would be a first for me.
cranheim
16 years ago
den69rs96,
I purchased a valve Setting kit for setting the valves in my BR600 from my dealer. It was p/n 4282 007 1001. This kit was for the BR600. If you have a different blower, the valve cover gasket may be incorrect. Check with your dealer on that one. It contained the special feeler gage, the valve cover gasket, and a washer. It costs about $10.00. There are no instructions with the kit. For some information on the adjustment procedure try URL http://www.cdcstihl.net/techtips/tips_v1n2_sm07.pdf
It may take you a little while to figure how to get the covers off the engine to get to the valve cover. Charles Ranheim
den69rs96
Original Author
16 years ago
Charles thanks a bunch. Exactly what I was looking for. $10 seems seems cheaper than the labor charge the dealer will charge to do this.
cranheim
16 years ago
By the way, I discovered the price for the valve cover gasket alone was more than the entire kit. I would guess a dealer would charge for an hours time plus parts, way over the $10.00 for the kit. Certainly, a good technician is worth the money if they do it right the first time. For the average homeowner, it might take years to accumulate 150+ hours. Then, by the time it may have to be done again, you will probably get a new model anyway. Charles Ranheim.