# Stihl MS180 run problem



## roypaun (Jun 26, 2010)

MY MS 180 will fire up for several seconds and then stop. When it fires up and I can catch it in time I can rev it up with little problem, but as soon as I release the throttle the motor stops. Then it is very difficult to re-start it (until it goes cold?). I have replaced the carb. I have a Spark (obviously) and i have checked the exhaust manifold (no spark supression though). Petrol is getting to the carb, have replaced the fuel system. I have no chain attached so am not using any oil in the oil tank. Could the fuel mixture be the problem (am mixing 50:1).
Thanks for any help and/or advice.


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## AVB (Nov 28, 2014)

*Re: MS180 run problem*

I am hoping that subject title is misprint as I think you mean Stihl MS180. If so is there any letter afterwards on id tag? There several versions of this saw.

First try upping them idle speed to it max. It might be that the idle speed is simpy too low. It does sound like an air leak however in the intake system. This of course includes all the crankcase sealing surfaces. This normally involves pressure and vacuum testing the crankcase.

Also since you no chain installed watch out for clutch spinoff.


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## roypaun (Jun 26, 2010)

Yes, apologies - just gwetting old !!!! It should have read Stihl MS 180, although I am not sure of any other nletter. I will check. Thanks however for the reply, much appreciated. Could it be anything to do with timing?


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## SABL (Jul 4, 2008)

Title fixed.......please continue.


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## AVB (Nov 28, 2014)

roypaun said:


> Could it be anything to do with timing?


Slim chance but not complete out of the question. There is only 2 things that can affect the timing on a 2C that I know of. That is a sheared flywheel and ignition coil electronic timing; unless, when points are involve but this doesn't points.

The problem your have can be any number things as everything got be working right. 2Cs are simple engines but can very frustrating to repair. Sometimes even well experience technicians can be given fits. 

It will take time to find this problem as you already replaced the carburetor. I would first do a compression check. If it is below 100 psi cold or hot the engine will not start normally. Second can be the metering lever height in the carburetor. This is set wrong at the factory by an inexperienced assembler. A setting that is too low will cause idling problems but setting too high will cause flooding.

The pressure/vacuum test requires the engine to hold 7.5 psi (.5 bar) of pressure or 7.5 psi (.5 bar) of vacuum. The vacuum test will check the oil seals as they tend to fail under vacuum. If either test fails then the source of the leak must be found. When pressure testing soapy water spray on suspected areas can help the leaks.


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## roypaun (Jun 26, 2010)

Thanks very much for that information. Unfortunately I can not do a compression test as I do not have the equipmwnt. I think I will replace the carb - again - but this time with the alternative carb (Webber?) which I believe has more adjustments available. It is certainly very annoynig !!


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## AVB (Nov 28, 2014)

Did you replace the carburetor with the genuine Zama C1Q-S57A(B) or was the Huayi or some other generic carburetor. I have been hearing of a lot problems the junk carburetors that China is shipping out especially the Ruixing knock offs lately.

As far as Walbro there a version that might work it won't have the snorkel top (just what I what it) over the metering diaphragm. It is the WT-325A but I think it is no longer available new but check with your local Stihl dealer. Now it only has an idle mixture screw in addition to idle speed adjustment; no high speed mixture adjustment.

If your in the US and have an Advance Auto parts store close then you might get one on the loan a tool program they have.

Personally I still got to get myself one of the pressure/vacuum testers. I am getting to the point that I needing one more often. It was just more important to get my air compressor motor replaced. I know I could have got whole compressor for what I paid for the motor but I needed CFMs of current compressor besides it served me well for 30 years.

If you decide to get a compression tester gauge set for you own use get the one that has the new 10mm adapter. I have had several MTD based trimmer that are using the new 10mm spark plugs.


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