Stihl MS310 Hard Starting

[Beltzington]

Gas, Spark, Air - Ops Checked Good

Saw starts in one or two pulls when it has been sitting on its base. Problem seems to occur when it has been turned on its side to do unimportant things like fill with gas and oil. I'm guessing it is flooding but curious as to why. Also is there a "best" method anyone has figured out to get excess gas from the system? I have tried holding the throttle wide open and cranking without any success after 10-20 pulls. Appreciate any advice as I am using all my energy trying to start the saw instead of cutting trees. TIA!

 

[bigballer]

mine had a small crack in the pickup line inside the fuel tank, it would start and run for a few seconds then die when throttle was applied.. not saying that is the problem but something you might want to look at..

 

[newbury]

Does it run well after starting?
If it's flooded pop the spark plug, give it a couple of pulls, replace plug.
Try running some Seafoam thru it.

 

[Treemonkey1000]

When is the last time the air filter was taken off and washed and dried and then put back on? Or replaced completely? If it floods that badly next time pull off the air filter and tip it on it's side for a few minutes with fuel in it. See if you notice any fuel coming out of the carb or any where. Like the other response leaky fuel lines or the diaphragm in the carb might be sketchy. Then try starting it with the air filter off so it sucks more clean air instead of through a fuel saturated air filter.. See what that does for you.

 

[DieselMonk]

sounds like it needs a carb kit and spark plug. However I would try running Seafoam throught the air intace a few times until she stalls with throttle applied and then mix some into the gas / oil mix too. I mix always 40:1 and my Stihl 034 had after 15 years: 1 spark plug, 1 carburator kit and 1 bar. That's it. My FS110 gave me problems earlier in the spring (hard starting, not running right idling and at full throttle) and I cured it with Seafoam. Runs like new now.

 

[arrow]

Gas, Spark, Air - Ops Checked Good

Saw starts in one or two pulls when it has been sitting on its base. Problem seems to occur when it has been turned on its side to do unimportant things like fill with gas and oil. I'm guessing it is flooding but curious as to why. Also is there a "best" method anyone has figured out to get excess gas from the system? I have tried holding the throttle wide open and cranking without any success after 10-20 pulls. Appreciate any advice as I am using all my energy trying to start the saw instead of cutting trees. TIA!

If you are in Georgia and usung a chainsaw now, you could be experiencing some type of vapor lock in the fuel line when you go to refuel after a hot work out. It restarts only after the saw has cooled which is usually having a saw upright. If you leave the saw on its side to cool down and it starts after 20 minutes, that will give you clues. Try refilling the saw before it goes empty and use premium gas. Peak inside the fuel tank after the saw has been running for a while and see if you can see the gas "percolating". That will also tell you that the fuel is overheating. It only takes 140* for gas to start boiling and thus create vapors. Your cap may not be venting as it should or it may be just too hot outside to be running a chainsaw on regular gas. Seafoam could help if indeed is vapor lock. As a result of fuel injection in cars, they have made gas with less btu's and vapor lock just is not a problem as it used to be when cars had carburetors. If it is not starting after the carb has run dry and you go to refill it with the saw cool, then you have carb problems of either a bad needle (flooding) or a bad diaphragm ( no gas). Again because of today's fuels they're making.

 

[Beltzington]

Appreciate all your suggestions. Finally got to working on the chainsaw and my original assumption was incorrect. Saw won't fire period. Took the air filter, exhaust off and verified the spark plug was firing when grounded but even with ether sprayed in the combustion chamber it will not turn-over. No idea how to proceed. Any other suggestions?

 

[Treemonkey1000]

You may want to pick up a new plug if you haven't already. If you can get your hands on a compression tester and see how much compression it has. I don't know what they should be running. One of the other brainiacs on here can tell you. Those would be the first two things.

 

[LD1]

Dont use ether on a 2-stroke and dont use seafoam either.

If it needs a "jump start" ditch the ether and just put a capfull (bottle cap) of 2-stroke mix in the plug hole.

As to your problem, is it indeed flooding or is it starving for fuel??? When it wont start after 20 pulls, take the plug out. Is it dry or wet??

If it has air and gas in the right amount AND spark, that only leaves one thing....compression. Do a comp test as already mentioned. When a saw gets tired, they get finicky and hard to start.

 

[arrow]

Appreciate all your suggestions. Finally got to working on the chainsaw and my original assumption was incorrect. Saw won't fire period. Took the air filter, exhaust off and verified the spark plug was firing when grounded but even with ether sprayed in the combustion chamber it will not turn-over. No idea how to proceed. Any other suggestions?

Ok this presents a different problem altogether. Low compression usually does not prevent a saw to start. They run crappy but unless a piston ring is actually broken, it could start with low compression. LD1's question is pertinent. No gas or too much? By any chance are the fuel lines wet? If you've got a good spark and put some gas in the carb and it starts, you know you are getting no gas. Replace all fuel lines.

 

[DieselMonk]

tried a new spark plug and propper gapped yet??

 

[arrow]

tried a new spark plug and propper gapped yet??

Can't go wrong with that suggestion and its the simplest solution first.

 

[Beltzington]

Well, just got the saw running but no idea why. Here is the long story:
Shiny new NGK plug correctly gapped per owner’s manual - No Joy
Compression checked at 100psi, low but acceptable considering I had to rig some washers to compensate for the long shank on my tester, I may not have had a good seal
Put a straw full of highest gas with top of the line Stihl oil directly into the combustion chamber - No Joy
Profanity concerning German Engineering - No Joy
More profanity concerning German Engineering as my Echo has work flawlessly for over 30-years - Still No joy
Put a straw full of fuel mix into the carb - No Joy - Wait it coughed
Set the throttle to the warm setting and pulled some more - Bingo, saw started, shuddered, spit some black fluid out the exhaust and is now starting and running like a BMW
Still not impressed with German Engineering
Thanks for all your advice and I would be interested in your assessment. Take Care!

 

[DieselMonk]

Spark arrestor in the exhaused plugged. all the gas cleaned it out some.

 

[arrow]

If the arrestor was plugged, the saw should of run for a short time, overheated and shut down by itself. After cool down , the saw should of restarted. Unless this was happening and we were not informed so this guess is as good as any. Your saw started because you primed the carb which obviously had no gas in it by itself. This could be a pressure problem of some sort. I'd go with insufficient spark from a worn out plug or gap right now. Other thing you may look at is your choke lever to make sure it is working properly and closing butterfly fully. I have also seen worn needles cause leak down and the carb empties out but this usually takes over night. There are so many things that can contribute to this stuff so it is always a crapshoot when doing cyber guessing as it relates to chainsaw problems. When it is warm out, chainsaws do not need too much choke and a "sputter" is not always the telltale to flip choke off. If it happens again and it is not "operator error", I'd do a complete carb and fuel path tune up or replacement. When I had to log during the summer ( ugh) there were some saws that required only one or two pulls with the choke on. If one was waiting for the "sputter" one flooded the saw. Mostly, this was with larger saws. At any rate, hope it stays joyful for you.