saw stalling

[metalspinner]

My saw started stalling when I tip the bar below horizontal.  I have a Stihl MS310.  The tank is topped off, but this has not happened in the past.  Any ideas?
Thanks, Chris

[sawguy21]

Sounds like an intake air leak. You need to pressureize the saw and check the gaskets and crank seals for leaks. I strip the saw down then dunk it in a bucket of water to check for bubbles.

[metalspinner]

One other thing that I just remembered...  A few days ago I picked up the saw off my trailer and noticed a fuel puddle running from the saw.  The tank was bone dry.  I thought maybe my cap wasn't on right.  I can't recall if it was on right or not.

[Kevin]

The tank vent may be suspect but I don't know where it is on that saw.
If you use compressed air for cleaning you may have damaged it.
Sometimes they are on the clutch side of the saw.
Other than that I would be inspecting fuel lines and searching for the location of the leak with a full fuel tank.

[Simonian]

Check your fuel line from tank to carb. It may be cracked and needs replacing.
The puddle may have been caused by vapor pressure in the tank forcing the gas out the cracked line.
Then it is possible that you have a stuck inlet needle. But check the fuel line first
>:(

[MDP]

If your saw has sat for a long time the gas can cause many problems in the carb, the wonderful gas they sell us now is more less void of stabilizers and turns to goo very quickly. You might want to pull the carb and give it a good cleansing along with checking the filter and vent like what was mentioned before.


Mark

[jdunmyer]

That business about old gas is interesting:

My 056 sat for nearly a year when we decided to cut some slabwood. It started up easily enough, but after 2 or 3 cuts, it siezed while in the cut. IIRC, I shut it down before it actually stopped, let it cool, then attempted to restart it. After a lot of fooling around, I took it to the local Stihl place where they told me that it was down on compression and needed an overhaul. They did that and it's been fine since, albeit not a lot of use.

We dragged 'er out the other day, it having been about a year since it had been run. Dumped out the gas that was in it and refilled the tank with gas mix that's probably also been around nearly a year. The saw actually started within a few pulls, quicker than many I've seen that were run just the day before. I let it warm up and took it easy during the first cutting, but it seems fine. Have cut slabwood several more times w/o trouble; that's the only usage this saw gets.

[metalspinner]

Thanks for the reply's everyone.

The gas is fresh. I have been useing it weekly. I will go check the fuel line for any cracks, but it will probably end up at the dealer, anyhow.  If I go poking around on it, I may make it worse. :  I will let y'all know what they have to say.

[simonmeridew]

Hi Metal:
The air vent on my stihl 34 AV is accessable when you take off the plastic cover at the back of the saw to check the air filter and spark plug. It's the odd looking  black plastic thing sticking up to the left rear of this compartment. The top part of this thing pulls off, and then there are a couple of screws to take apart to clean it out. Honestly your dealer probably wouldn't charge you much at all to check it, it doesn't take 30 seconds to take out.
simonmeridew

[scottr]

metalspinner , if your idle setting is rich then tipping the bar down will cause a slower idle or stall . If you set the saw on the ground and let it idle for 20 seconds and roll it to the left or right side does the idle spped change or stall . Have you recently lowered the idle speed ?    Scott

[metalspinner]

Here's an update to the problem with my saw.  The fuel line was cracked.  So they replaced that and did a routine maintenance check.  Air filter, spark plug....

It runs like a champ now.  I don't know what specifcally caused it to stall.  My guess is the fuel line.  They didn't say wether or not they tweaked the carb.  The total bill was $68.  Some day I should go take a small engine class so I can take care of these type of things myself. :P

[Simonian]

You do not need a small engine class. all you need to do is look, think and have a small number of tools on hand that will fit the fasteners  on your saw. Remember God did not make your saw, people did. By removing a bolt or 2 not going to cause your saw to bleed to death.
You now have my permission to do your own work on your own saw.
I must thank you for your help as it gives me a good idea as to what a dealer will charge for a simple fix.