BR600 help.

BrianSki

Active Member
Runs bad, won't run. Not sure what Stihl did to this thing. My son bought it used. Ran for a while, then said it bogs no power. Asked if I can look at it.

I think Stihl made a mess out of this thing. BR600 blower. I do some looking online and shows they took a 2 stroke and put valves on it. On place online say to change the oil in the engine every 25-50 hours. Said to used 5w40 oil. Then I look at a manual and it shows to use 2 stroke oil in the fuel and the engine does not take oil for the crankcase. Primer bulb bad and it shows 2 models of primer bulbs. Everyone is selling the wrong one. Mixture screws are some oddball Octogaon ones. Ok done ranting and tell you whats up.

Son told me it ran bad and he put a new carb on it. Still ran bad. The new carb says Stihl on it. About all I know.

I started with new fuel filters, new plug, air filter and primer bulb. It would fire up pretty easy, but the throttle made no difference. Barely a change in RPMs. (under 50 RPMs with a tach.) At first I thought maybe the linkage cable is off. Nope I can see it turn the linkage on the carb. full throttle or idle no difference. No bog just idles. Which is very strange to me. Tried tweaking the mixture screws, did not do very much at all.

So I decide to check the valves. .004 Intake was off a bit, 1/8 of a turn. Exhaust about spot on. (Intake does not seem to open much?? maybe me?) I go to start and barely get it to run. Can't even get it to idle now. I get some smoke out of exhaust and some random hard pulls.

Not sure where to go from here. Ideas?? Thx BTW usually pretty good with engines.
 
Ok, after some research, these engines are called a 4mix and the cam gears have a way of melting. Sounds about right is I am seeing the valves not open very far. # 4282 030 1801

Will update when I dig further.
 
Ok, after some research, these engines are called a 4mix and the cam gears have a way of melting. Sounds about right is I am seeing the valves not open very far. # 4282 030 1801

Will update when I dig further.
Yeah, it is a 4mix engine. The BR600 BR700 and BR800 are great blowers. I have a BR600 that is 20 years old, used to use it commercially, and is still going strong. Rarely does the cam gear melt.
The carburetor is a Zama if it is OEM, not Stihl. Although Stihl did buy out Zama.
Highly doubtful it is a sheared flywheel key. Take it to a shop if you can’t figure it out. Run it without the fuel cap on for a bit. Also, make sure the tank vent is working properly.
 
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