# Stihl backpack crankcase air leak?



## SteelieMark (Apr 16, 2016)

I have an older(07'?) Stihl B 500 backpack blower; it wouldn't keep running after start and warm up, when I hit the throttle it would die but re-start with the same results. Brought it to a dealer who put a new ignition module, carb primer(said it was cracked) new air filter . Says the problem is the crankcase is leaking air and needs to be split and repaired with RTV. Big $ Never heard of this- any small engine mechs out there want to weigh in?

I get a strong feeling the kid doing the repair doesn't really know whats wrong and is working on flat rate. He offered to let me take it back in parts "to help us both out". Qu'est-ce ?


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## apemoreton (Apr 16, 2016)

I honestly don't think this will be your problem as they're basically a 4 stroke engine but they run on 2 Stroke and the 2 Stroke fuel lubricates them. 

Is the machine wet/ damp around the pull start area? 

When using it and blowing in the wet does it blow a oily residue.


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## ANewSawyer (Apr 16, 2016)

I am not sure a 4-mix can suck air in the crankcase. I am not sure they have a traditional transfers.

@backhoelover


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## jimrb (Apr 16, 2016)

I have had engines fail to rev up. New carb gasket kit which includes a new fuel pump gasket worked every time so far. A stiff fuel pump gasket is one that will not work. 

I also have a Stihl 110 Kombi head. I adjusted the valves which helped it run better. My valves were quite loose. That engine did not have carb problems.


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## backhoelover (Apr 16, 2016)

sure can. need to pressure test seals are none for going bad


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## ktoom (Apr 18, 2016)

The crankcase still needs to be sealed. The last 3 br600's I serviced had crankcase leaks.


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## albert (Apr 19, 2016)

Check the fat pulse hose going to the carburetor. It needs to be a tight fit on both ends. Check the crankshaft for play, seen a few with bad bearings, one was run until the coil laminations and fanwheel got destroyed.


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## ktoom (Apr 19, 2016)

I second that on the fat impulse hose. I had a few that were hard as a rock on some fs110's. When I pressure tested the motor, they were leaking on the nipple.


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