My Stihl chainsaw won’t start!!! Step by step diagnoses and how to repair

This video is a full length step by step view on how I diagnose and fixed my MS180c chainsaw. I show and tell my thought process as I sort out the problems and make the appropriate fixes. Turns out it was a carburetor related issue that couldn’t be repaired with a fresh carb rebuild kit. I had to buy a replacement carb and that turned out to be the trick!

Check out my latest videos on my channel!

Cheers,

Dave

[ChristopherTreadway]

Aren’t you glad you did this video so all the experts could chime in about how to really do it? Makes me wonder why they were watching the video in the first place if they already knew everything. Thanks for the information

[robertdrnsdad]

Thanks Dave, I like seeing people try to make the existing parts work without just jumping to a new carb. Word of advice and this comes from experience, be very careful where you stick wires in these carburetors. Only do this with passage ways, not CHECK VALVEs. You noted before that one of those were check valves. If you poke a wire through the check valve, guess what ? Yep, you have likely just ruined the check valve. I have found its best to try to spray carb cleaner or some premixed fuel through the check valves. The trick is you have to find which way to spray or push the fuel through it because check valves are 1 way devices. Another way is to get a piece of fuel line and press up to the check valve and see if you can push or draw air through it, but DON'T use the air compressor. As said, I know because I have done it.

[deweylee]

Hey David I can tell you why the film you found on metering diaphragm. I've ran into this many times. Who ever owned the saw got a brain fart and put chain oil in the gas tank instead of where it was supposed to go. When I say I've run into before, I'm talking at least one saw every year. Most of the time it is steel saws that I get like that. Good video showing people who don't know how to track down there problems.

[smca]

Great breakdown, worth watching to the end...my 2 cents is, I had a spark plug that sparked really well, but did not start, replaced plug and it's back to new, this has only happened to me twice in 60 yrs....they are frustrating at times...

[BkLiveWire]

Picked up a used ms170. Had great spark and compression but needed carb work. After I did a complete rebuild on it, I could only get it to (burp) on full choke. After that no matter what you did it always flooded the engine. Since these carbs don’t have H & L screws just an idle adjustment, the idle screw was set so low that it wouldn’t even start. After I increased the idle speed, it runs good now.

[davidlis]

At least you are honest about not starting.
I remember those old Briggs and Stratons engines. By time you start them, you are to tired to use the equipment.

[LordBLB]

Great stuff!

My first try when I'm presented with this problem on my saw, is to dump the fuel and replace it with Stihl 50-1 mix from the local Stihl dealer. It's usually because I've got old gas in there that's been sitting too long. 90% of the time my saw will fire right up after a few pulls with the new fuel. This video, is what happens the other 10% of the time, lol. Great tutorial.

[magicone]

Mentioned that you are using BRAKE. Cleaner. Misspoke? Brake cleaner can dissolve rubber, nitrile parts as well as plastic. Behind the welsh plugs are Plastic components and the needle vale yip send seat could be as well. Never use break cleaner!

[magicone]

When the carb is off ALWAYS shine a light into the intake and look at the surface of the piston. Usually no vertical scratch are seen but if there are scratches and they cross thru the rings there will be compression issues. Usually there isn’t much wrong on the intake side as most damage happens on the exhaust side which requires muffler removal to view the condition of piston and cylinder wall.

[markmacdonald]

The 'ol bar oil in the gas tank trick eh! Looks like they mixed them up, look in the oil tank for the gas lol. When testing the saw, you need to tighten the carb correctly to ensure there is no air leak. maybe flush the fuel line, probably full of that oil as well. Enjoyed the video.

[tuckerandi]

Very informative i have a 170 so saving this one for a guide if I ever have issues

[ratomanche]

Awesome! Thanks so much. Very informative and detailed.

[mlocker]

Someone put bar oil in the fuel tank instead of the bar oil tank. I have had this done several times on saws i have worked on

[craigwalsh]

Dave does have a small engine, I've seen it, very small but works

[magicone]

Always blow off the crap before dismounting carb as it will help to keep crap out of the intake

[aarondavis]

given how gummed up that carb was one thing i would've tried and has worked for me before if it doesn't work after cleaning you're probably 99% of the way there and just need a little push so what i do is:
1. load up the tank with "VP Fix It Fuel" (fuel with carb/injector cleaner in it)
2. give it about a teaspoon of fuel down the spark plug hole, and pull start to give it that few seconds of operating RPMs to suck the fix it fuel into the carb as much as possible.
3. let it sit over night.
4. repeat step 2
5. at that point it might just keep running, but if not, attempt to pull start as normal if you can get even a single chug out of it you're on the right track.
6. if pull starting still isn't working assess your confidence in whether it will work and repeat start at step 3 again until such a time you have no faith.

[marcuscicero]

just installed a rebuilt carb with all new fuel lines. got a blip dribbling in fuel straight into the carb. no primer bulb. gonna remove carb and with a syringe pull fuel into the new line coming from fuel tank. liked your fueling direct through the spark plug hole directly into the top of the cylinder.

[johnclarke]

How to install the choke lever - push the choke butterfly closed with your thumb and the choke lever will go right into the carb lever.Install the long part of the lever in the Master Control Lever, first.

[Greg_Gatsby]

Doesn’t that model have a spark arrester screen behind the muffler? It could be clogged from idling.

[bradallen]

Hi from Oz. Great vid Dave. You’re a patient mechanic educating us home wanabees. I’m attempting to get a Walbro HDA-23 carburettor working again by fitting a new carby kit but don’t have the luxury of buying a new carby if it doesn’t work because they don’t make them anymore. The carby is off a classic Sashs Dolmar 116 chainsaw. Hope I don’t have to throw it away.