# New Stihl MS390 won't start



## Kenster (Mar 27, 2010)

I bought a new, muffler modified 390 - 16 inch bar - about a month ago.  Today is the first time I have tired to fire it up.   I mixed a fresh batch of gasoline and 50:1 oil.

I read the owner's manual instructions several times.  I verified that it is set for summer operations.  Because it has been sitting dry for over a month I pulled the rope through slowly four or five times to prime it per the book.   I set it for cold start.  (Ignition switch Lever all the way down.) Pressed the decompression button and began the starting attempt.

I must have pulled over 100 times now.  I don't think it's flooded.  I don't smell any gasoline but I did remove the spark plug to check it.  It only had the very thinnest hint of oil/gas on it.   I wiped it off anyway and reinstalled.   No change.  

A couple of questions come to mind.
 (1)  The owner's manual in the very  first step under starting says to press the Decompression button.  Later it says that after it begins to run to Press the Decompression button even though it also says the button will automatically disconnect as soon as it starts.

(2) When doing the pull start, are you suppose to be pulling the trigger the entire time?   With my little Craftsman, I usually don't pull the trigger until right after it begins to fire up.

So this is quite frustrating.  I expected some learning curve with the new  saw but it seems like I'm following all the steps.  I'd like to conquer this today so if you have time for replies and advise, I'm standing by.

Thanks!
Ken in Bellville TX


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## North of 60 (Mar 27, 2010)

Your trigger should lock open by itself after you squeeze it when doing the cold start routine.


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## smokinj (Mar 27, 2010)

choke you done right after hearing the very first burb then flip the chock up one notch then press decomp and fire the sucker up....and to check if its flooded and I bet it is pull the air filter off... and never pull it 100 times it just wears you out...




"""""(2) When doing the pull start, are you suppose to be pulling the trigger the entire time?  With my little Craftsman, I usually don’t pull the trigger until right after it begins to fire up."""""

when you hear a sign of life filp the choke up on knotch no need to hold trigger!


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## Kenster (Mar 27, 2010)

Jay, I don't know what a "burb" is suppose to sound like.  But it's not even close to showing signs of life.  It almost sounds as if there is no spark.   I just went out for another round.  After a few pulls on full choke I moved it up one notch.  The sound changed.  Maybe a little deeper sound.  Still no life and it's just about worn me out.

My Craftsman always fires up after I pull four or five times on full choke, then move it half choke.  First time on half choke it nearly always fires right up.   The gent I bought if from on eBay said that I can call him and he will talk me through it.  If that doesn't work I guess I'll take it to Western Auto Stihl dealer about 18 miles away on Monday and see if they can help me.  The lady that runs that place sure seems knowledgeable based on my visit with her a couple of days ago.


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## smokinj (Mar 27, 2010)

Kenster said:
			
		

> Jay, I don't know what a "burb" is suppose to sound like. But it's not even close to showing signs of life. It almost sounds as if there is no spark. I just went out for another round. After a few pulls on full choke I moved it up one notch. The sound changed. Maybe a little deeper sound. Still no life and it's just about worn me out.
> 
> My Craftsman always fires up after I pull four or five times on full choke, then move it half choke. First time on half choke it nearly always fires right up. The gent I bought if from on eBay said that I can call him and he will talk me through it. If that doesn't work I guess I'll take it to Western Auto Stihl dealer about 18 miles away on Monday and see if they can help me. The lady that runs that place sure seems knowledgeable based on my visit with her a couple of days ago.



pull the air filter off and see if it smell of gas real heavy.... it will sound different when you change the setting on the choke I bet its flooded real bad and if so leave the air-filter off and let it air out....the burb on a 390 going to be faint if you will you should get one in the first couple pulls I miss the burb on my 361 more than I care to admit. When you miss it you can pull all day long and it sucks

burb can be very faint!  soft


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## webie (Mar 27, 2010)

Get your self a new plug , skip the decompression relief .  It will be a little tuff to pull over but I bet it starts then .  Jay I never use the decompression button the first start of the day . That took care of the flooding problem. I havent had a flooded stihl since .


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## LLigetfa (Mar 27, 2010)

I hate seeing the gas dry out of the carb.  It tends to dry out and curl the little flapper valves on the impulse pump.

If you are pulling it with full choke, you just have to be able to smell raw gas at the exhaust if the gas is getting pumped.  Loosen the gas cap if it isn't pumping.  Could be a plugged vent.

If it's flooded, pull the plug and stick a propane torch in the plug hole and slowly pull the cord.  It will suck in the flame and dry out the inside of the cylinder.  It will also shoot out flame so don't be hetting your hair near it.  Dry the plug off with the torch too.  Try a new plug.

If you want to see it there is spark, take out the plug, stick it in the boot, and while holding the plug, pull the cord.  If it doesn't send a big shock into your hand, you have no spark.  Don't do it if you have a weak heart.


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## oldspark (Mar 27, 2010)

You could put just a dab of gas in the carb and see if it fires, the way you described the plug when you pulled it I don't think it is flooded.


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## Tony H (Mar 27, 2010)

If you pulled it that manytimes it's flooded or it's getting no fuel pull the cover pull the plug dry it off or replace it. If you cave a compressor use it to blow off the plus let it sit use the air comp or the propane to dry it out. When you go to start it this time set the choke switch all the way down DON"T pull click the switch up one and give it a few pulls.
For normal starting choke on lever down pull a couple times see if you hear it sound like it might start the burble then flip the lever up one and pull


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## RowCropRenegade (Mar 27, 2010)

If you can tolerate being shocked, twist out the plug, reattach plug wire and pull with spark plug against your arm.  If you don't jump when you pull it, it narrows it to electrical.  If you do jump, my best guess is breather.


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## Kenster (Mar 27, 2010)

Okay... I got it started.  I checked the plug three times.  It never seemed _that_ wet but I wiped it off well each time.  I took off the air filter.  It had a faint smell of gasoline but not real strong.  The carb looked clean and had very little gas.  
I put it all back together.  With the switch in the "Off" position.  I pulled it a few times, which I believe is a method to help drain a flooded system.  I then put it on the "Run" position and pulled a couple of times.  It sounded like it wanted to start.  I put the switch on the "warm start," which I believe is sort of a half choke (?) and it fired right up!!

It blew smoke for a few seconds then it cleared up.  Ran like a champ.   I'm used to a little 32cc Craftsman so this MS390 with 64CC and modified muffler sounds like the difference between a Cushman Scooter and a big Harley.

Now, I don't want to have to go through this every time I do a cold start.   I think what I need to do is, with full choke, pull it a few times then move it to half choke, which should allow it to start up.  Right?

Not sure what to do about the decompression button.  Don't use it for the first start of the day?   After I got it started today I did a little bit of light cutting.  I'd sit it down for a while and come back and start it up again and it would fire right up.  I never touched the decompression button again.  So, I'm not sure just when I should use it.

Thanks for the suggestions and I would appreciate any follow up advice you can give.

Ken


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## webie (Mar 27, 2010)

I am hopeing for the best for you , This is the saw you got off of EBAY that had a muffler mod done to it ?  You may want to pull the muffler off and take a look at the piston . Hopefully the guy didnt lean this thing out to much and make scrap out of it . Your little gas on the plug  makes me kinda wonder . If your compression is up to snuff . I would say after this if you still cant get it going you might want to test the service at that Stihl dealer you found close by .


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## thinkxingu (Mar 27, 2010)

Starting method for every Stihl I've ever run:

When COLD:
1. Make sure bar oil/gas tanks filled
2. Pull trigger and put lever all the way to full choke
3. Pull over 2-4 times until you hear a 'pop' (like it will *almost* start)
4. Put lever to run position
5. Pull over once
6. Cut wood

When HOT (within a few hours even):
1. Put lever to run position
2. Pull over once
3. Cut


S


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## webie (Mar 27, 2010)

Kenster said:
			
		

> Okay... I got it started.  I checked the plug three times.  It never seemed _that_ wet but I wiped it off well each time.  I took off the air filter.  It had a faint smell of gasoline but not real strong.  The carb looked clean and had very little gas.
> I put it all back together.  With the switch in the "Off" position.  I pulled it a few times, which I believe is a method to help drain a flooded system.  I then put it on the "Run" position and pulled a couple of times.  It sounded like it wanted to start.  I put the switch on the "warm start," which I believe is sort of a half choke (?) and it fired right up!!
> 
> It blew smoke for a few seconds then it cleared up.  Ran like a champ.   I'm used to a little 32cc Craftsman so this MS390 with 64CC and modified muffler sounds like the difference between a Cushman Scooter and a big Harley.
> ...


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## southbound (Mar 28, 2010)

thinkxingu said:
			
		

> Starting method for every Stihl I've ever run:
> 
> When COLD:
> 1. Make sure bar oil/gas tanks filled
> ...




All I have to add is it does not take a lot of fuel to flood one of these out...Yes I will admit to flooding out my 290 more so when it was new to me and the plug was never that wet and the smell of fuel was never that strong...

Also for the decomp valve push it in before you lock the trigger and then when you hear the almost start you move up the switch and it should fire right up.....


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## Kenster (Mar 28, 2010)

thinkxingu said:
			
		

> Starting method for every Stihl I've ever run:
> 
> When COLD:
> 1. Make sure bar oil/gas tanks filled
> ...



You don't mention ever using the half choke position.  Do you not ever find it necessary to do so?


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## oldspark (Mar 28, 2010)

thinkxingu said:
			
		

> Starting method for every Stihl I've ever run:
> 
> When COLD:
> 1. Make sure bar oil/gas tanks filled
> ...


My 045 starts just like that and has for 30 years, have not figured out my 028S i bought a year ago, my 09L needs a shot of gas in carb after it has set much over a few days.


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## thinkxingu (Mar 28, 2010)

Kenster,
     I should have made it more clear: when you hear the 'pop' after 2-3 pulls on full-choke, you pop it down to half which keeps the trigger still pulled.  THEN you pull it once, wait a second, and hit the trigger.

Run.

S


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## southbound (Mar 28, 2010)

fuel and oil

set the chain brake

push in decompression valve

lock trigger by pulling trigger and moving switch all the way down

pull until it almost starts

move switch up one notch

pull till starts 1 or 2 pulls

at this point you will have to pull the trigger to unlock it and the switch will go from choke to run on it's own  you then can release the chain brake and start cutting....

Next start of the day

set chain brake move switch down one notch to run and pull cord...


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## WNCburner (Mar 28, 2010)

southbound said:
			
		

> fuel and oil
> 
> set the chain brake
> 
> ...




This is exactly how my MS 361 likes to be started.  The first few times I tried to start it, the saw flooded and I was very frustrated.  The "blurp" on my saw was easy to miss because it is such a minor event--not at all like my older Stihls which actually run for a few seconds on full choke.  It's like the saw fires for one stroke of the piston, very subtle and quiet event.  Sometimes I don't even hear it, I just see the decomp button pop up and know it's time to switch to half choke.


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## smokinj (Mar 28, 2010)

Kenster said:
			
		

> Okay... I got it started. I checked the plug three times. It never seemed _that_ wet but I wiped it off well each time. I took off the air filter. It had a faint smell of gasoline but not real strong. The carb looked clean and had very little gas.
> I put it all back together. With the switch in the "Off" position. I pulled it a few times, which I believe is a method to help drain a flooded system. I then put it on the "Run" position and pulled a couple of times. It sounded like it wanted to start. I put the switch on the "warm start," which I believe is sort of a half choke (?) and it fired right up!!
> 
> It blew smoke for a few seconds then it cleared up. Ran like a champ. I'm used to a little 32cc Craftsman so this MS390 with 64CC and modified muffler sounds like the difference between a Cushman Scooter and a big Harley.
> ...





Yea!now it will get easier each time....3-4 pull maxium


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## webie (Mar 28, 2010)

Just another idea here if you want a helping hand without useing the decompression release . Install an elastostart recoil . It helps alot . I have them on all my saws 026 on up . only the 460 do i use the decomp  alot , or if it gets towards the end of the day and I am tired after starting the saw about 50 times .


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## Kenster (Mar 28, 2010)

Do these saws require no priming for a cold start.  Some of my other equipment has a little soft, round bulb that I pump a few times to prime it before starting.  The owners manual says something about pulling the rope slowly a few times with the switch off to prime it but I thought that was for the first start EVER, not the first start of the day.

Thanks for all the help and suggestions!  I'll need a little practice being able to recognize the "Burble" to avoid flooding it all the time.  

I decided before I sent this post I'd go out and try to fire it up today.  I did use the Decompress button. On the third pull on full choke it started to fire, not just a pop.  I moved the switch to half choke.  One pull and it fired right up!

Obviously, yesterday's flooding was operator error, not mechanical malfunction.  I used to teach technology to other teachers.   We had a term:  PICNIC.   Problem In Chair.  Not in Computer.

Cheers!


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## smokinj (Mar 28, 2010)

Kenster said:
			
		

> Do these saws require no priming for a cold start.  Some of my other equipment has a little soft, round bulb that I pump a few times to prime it before starting.  The owners manual says something about pulling the rope slowly a few times with the switch off to prime it but I thought that was for the first start EVER, not the first start of the day.
> 
> Thanks for all the help and suggestions!  I'll need a little practice being able to recognize the "Burble" to avoid flooding it all the time.
> 
> ...



no priming...you have it down now just rember its going to burb within the first 3 pulls I will go ahead and move the choke switch after 3 even if I didnt think it did...


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## SPED (Apr 1, 2010)

One thing my stihl dealer told me when I bought my 290 was never pull more than 4 times with the lever all the way down on full choke.  He said he picked that up right from a stihl rep.  So even without a pop he said move it up a notch after 4 pulls. So far has worked for me but mine isn't even broken in yet.


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## Flatbedford (Apr 1, 2010)

The method described has always worked for my two Stihls. I loaned my MS180 (never again) to a neighbor. I filled both tanks, and started it for him. I shut it off and let him take it. He can back a few minutes later to tell me it wouldn't start. I could do nothing to get it to start. I had to pull the plug and let it dry out. He must have used the choke again and fouled the whole thing up. He walked back to his house with it running because he didn't think it would start again. Now that I know him a little better, I should have known that he would folk it up anyway. If you try some other routine to start your Stihl saw, it probably won't start.
I also will not loan out either of my saws again.


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## smokinj (Apr 1, 2010)

Flatbedford said:
			
		

> The method described has always worked for my two Stihls. I loaned my MS180 (never again) to a neighbor. I filled both tanks, and started it for him. I shut it off and let him take it. He can back a few minutes later to tell me it wouldn't start. I could do nothing to get it to start. I had to pull the plug and let it dry out. He must have used the choke again and fouled the whole thing up. He walked back to his house with it running because he didn't think it would start again. Now that I know him a little better, I should have known that he would folk it up anyway. If you try some other routine to start your Stihl saw, it probably won't start.
> I also will not loan out either of my saws again.



someone ask me to loan them a saw I hand them the 460 and they dont even grab it and then you here can you cut it for me.


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## xrayman (Apr 2, 2010)

I have a new 390 also, there's a "spring" on the choke run kill lever, check that if it gets bent it wont start worth a darn. Mine wouldn't start last weekend it had popped off the lever, did a field fix and took it to the shop to have a new one put in. I bought 2 more to have as spares cost a whole 2 bucks, and they showed me how to replace them.


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## HittinSteel (Apr 2, 2010)

smokinjay said:
			
		

> Flatbedford said:
> 
> 
> 
> ...



Hahahahaha perfect solution Jay Think I could convince my wife that is why I need a Ported 395XP?


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## smokinj (Apr 2, 2010)

HittinSteel said:
			
		

> smokinjay said:
> 
> 
> 
> ...




lol that 372 will do the the job......


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## HittinSteel (Apr 2, 2010)

Yeah with the muffler opened up it scares or annoys most people. I bought a Wild Thing last year for $30......... I loan it out to anyone that can start it.


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## Highbeam (Apr 2, 2010)

I've never been one to set the chain brake when starting a saw. What's the purpose of that? Just so that you don't saw your leg off? Well, I'll have plenty of chances to do that later on if I want to. Is there any actual reason other than safety to set that chain brake?


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## smokinj (Apr 2, 2010)

Highbeam said:
			
		

> I've never been one to set the chain brake when starting a saw. What's the purpose of that? Just so that you don't saw your leg off? Well, I'll have plenty of chances to do that later on if I want to. Is there any actual reason other than safety to set that chain brake?



with my 460 28in. bar I dont want to cut the ground..and I have a habit  to start them all with the brake on. Dont know if its right or wrong just what I do.


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## southbound (Apr 2, 2010)

Wile at the shop yesterday I was told not to set the brake ever it was only a safety and I would ruin the clutch drum if it is used all the time....

Not at start up and not when at idle and not in use....

I think I will keep using it all the time as I always have tho...


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## LLigetfa (Apr 3, 2010)

Some models of saw automatically engage a second braking system whenever the saw is idling.  The Stihl MS 362 C-Q is one of those.

http://www.stihlusa.com/chainsaws/chain_brake.html


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## mliiiwit (Sep 25, 2012)

I have on 039 that is nearly impossible to start after it has warmed up.  Is the same true for it (no more than run setting on the run/choke lever)?  If so, how many pulls should one expect before it fires?  Thanks!!


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## MasterMech (Sep 25, 2012)

mliiiwit said:


> I have on 039 that is nearly impossible to start after it has warmed up. Is the same true for it (no more than run setting on the run/choke lever)? If so, how many pulls should one expect before it fires? Thanks!!


 
Old thread but here we go....

Warm saw should be a 1 tug re-start.  Just flick the switch to run and go.

You can try the half-choke position too (doesn't really choke the saw, just cracks the throttle) if the saw doesn't reliably fire on 1 pull (but it should).  Squeeze trigger and go to full choke like a cold start then flick the switch up one position.

Cold Stihl with no primer bulb can take 6-7 pulls to get it primed and rolling.  Listen for any kind of pop, cough, or fart.  The least little burble and she's ready.

Decomp is optional depending on the operator.  Use it if you want.  Should always pop back out when the saw burbles. Punch it in again and give it the last tug.  Often a warm saw is much easier to pull than a cold saw so I only wind up using it on a cold-start.


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## golfandwoodnut (Sep 25, 2012)

My 390 takes 5 pulls on full choke, then burps, the half choke and it goes.  My 880, starts faster.  I guess I could try to flip it up at 3 or 4 without a burp. 

I did have one time when it just would not start.  My easy trick to see if there is a spark is to pull the plug and leave the line on, pull gently and look for a spark.  If no spark you know there is an issue with the electronics.  Mine was a coil wire came loose that the stihl rep fixed for free.


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## amateur cutter (Sep 25, 2012)

Skip the decomp valve completely imo. Other than that, 3-4 pulls on full choke cold, go to next click & she'll fire up. Only saw I ever used the decomp valve on was an old Mac. That mutha bucked every time you started it, & it had enough cc's to dislocate your shoulder. A C

Oh yea, I'd make sure that saw is properly tuned if somebody else modded it too.


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## nate379 (Sep 26, 2012)

I actually put a regular cord/handle on my 460 after I broke the elasto start when I pulled it without the decomp button pushed. Didn't surprise me at all, thought it was going to break everytime I fired the saw up.



webie said:


> Just another idea here if you want a helping hand without useing the decompression release . Install an elastostart recoil . It helps alot . I have them on all my saws 026 on up . only the 460 do i use the decomp alot , or if it gets towards the end of the day and I am tired after starting the saw about 50 times .


 
As far as the chain brake I very rarely use it.  About the only time I can think of is it I'm hand filing the chain.


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