In loving memory of Kenis D. Keathley 6/4/81 - 3/27/22 Loving father, husband, brother, friend and firewood hoarder Rest in peace, Dexterday

Stihl MS310 has me stumped.......

Discussion in 'Chainsaws and Power Equipment' started by Scotty Overkill, Feb 12, 2017.

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  1. Scotty Overkill

    Scotty Overkill Administrator

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    Saw ran great till I ran it out of gas one time last summer (while it was in a cut), refueled it and started it, falls flat on its face under throttle....

    I tried everything.....checked the fuel tank vent bulb, changed the fuel filter, looked for holes/tears in the fuel line, changed the air filter, checked spark arrestor screen, changed the spark plug, tore carb down, cleaned and rebuilt......nothing works.....

    The factory carb has those dammed limiter screws that aren't removeable, so I cannot tear it the whole way down to inspect/clean them....that or the ignition are the only two things I didn't check. Saw has good vacuum/compression, so I've ruled out those possibilities. While I had the muffler off, I went ahead and did a port job/new outlet on it......

    20170211_205936.jpg

    20170211_205943.jpg

    I went ahead and ordered an adjustable aftermarket carburetor last evening......I'll see if that fixes the problem...
     
    Scotty Overkill, Feb 12, 2017
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  2. Certified106

    Certified106

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    No input from me but you peaked my interest........
    Subscribing to see what it ends up being. She should be loud after the muff mod....... :thumbs:
     
    Certified106, Feb 12, 2017
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  3. Scotty Overkill

    Scotty Overkill Administrator

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    From what little it ran, the saw sounds pretty wicked now...

    I didn't go too radical, but I did open up the muffler some, these things are choked down pretty bad on the backside of that spark arrestor plate.
     
    Scotty Overkill, Feb 12, 2017
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  4. Boog

    Boog

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    My neighbor had a 310 that acted up on him about 2 years ago. Symptoms were quite the same as yours. Could not find anything wrong either after trying all the "logical" things you would expect. While checking out another good used plug to try in it I felt that the spark looked weak when grounding it against the cylinder. He ordered a new coil for it that I installed for him. Bingo! That was the winner!
     
    Boog, Feb 12, 2017
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  5. hdtoolmkr765

    hdtoolmkr765

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    Scotty, not sure what you mean by the limiter screws that you can remove. You mean it has the caps over the screws? If so, just run a drywall screw in them and pull out with a pair of pliers, then the screw will come out. One you tune the saw where you want it, you can snap them back in. I've also seen the exact scenario on a couple of saws that had a cracked fuel line inside the tank. I know you said you checked the fuel line, I know I am in the habit of only checking it from the tank to the carb, but just checking to see if you checked between tank and filter.
     
    hdtoolmkr765, Feb 12, 2017
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  6. brenndatomu

    brenndatomu

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    Sounds pretty broke...better send it over here for a proper burial ;)
    I was gonna suggest the line in the tank too...BTDT
     
    brenndatomu, Feb 12, 2017
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  7. Scotty Overkill

    Scotty Overkill Administrator

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    I'm going to try the replacement carb, if that don't fix it, I'm ordering a coil.....
     
    Scotty Overkill, Feb 13, 2017
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  8. Scotty Overkill

    Scotty Overkill Administrator

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    I'm going to pull the fuel line completely out of the saw and check it again, but from what I could tell, it looked ok.
     
    Scotty Overkill, Feb 13, 2017
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  9. hdtoolmkr765

    hdtoolmkr765

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    I would almost bet money if you pulled the limiter caps and pulled the H screw and blew carb cleaner through it, it would be good to go. If you rev it slowly under no load, will it spool up to WOT?
     
    hdtoolmkr765, Feb 13, 2017
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  10. Huntindog1

    Huntindog1

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    you said "checked the fuel tank vent bulb"

    So did that mean you checked the bulb and gas tank vent?

    My husky saw has a bulb and a separate vent.

    I was able to help the vent issue on my saw by cracking open the gas cap then the saw would start.

    Then it would build up a vacuum again and act up. Then I would have to crack open the gas cap again.

    I have read those bulbs have like check valves in them so good thing you check it out als0.

    Good Luck !
     
    Huntindog1, Feb 13, 2017
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  11. Scotty Overkill

    Scotty Overkill Administrator

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    Yes thats pretty much what its doing, once it hits WOT it falls on his face. I'll try that tonight. I went ahead and bought a cheap aftermarket carb on ebay, at any rate I'm betting that's the whole problem. I've rebuilt and troubleshooted enough of them....lol
     
    Scotty Overkill, Feb 13, 2017
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  12. Scotty Overkill

    Scotty Overkill Administrator

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    This saw has a weird "bulb" on the fuel tank vent line......it clips under the carburetor.
     
    Scotty Overkill, Feb 13, 2017
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  13. MasterMech

    MasterMech The Mechanical Moderator

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    Just a check valve. Gets the tank vent up higher and keeps it cleaner.
     
    MasterMech, Feb 13, 2017
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  14. Scotty Overkill

    Scotty Overkill Administrator

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    Well, the 10 dollar chinese replacement carburetor arrived today, I installed and tuned it, saw runs like a dream and cuts like an animal again.....

    I'll rip the factory carburetor completely down and give it a ride in the hydrosonic cleaner sometime down the road. For now, the saw is good to go. Muffler mod sounds badazz, too! Now I'm thinking about doing a timing bump, just a tiny advance to gain me some VVRROOM....

    I love having this saw on the job, it's a good saw to pull up into the tree for intermediate cuts on the trunk when needed.....
     
    Scotty Overkill, Feb 21, 2017
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  15. Eric VW

    Eric VW Moderator

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    Eric VW, Feb 21, 2017
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  16. Certified106

    Certified106

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    Glad to hear you got it going good as new!
     
    Certified106, Feb 21, 2017
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  17. Huntindog1

    Huntindog1

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    Wish they made a cheap chinese carb for the HDA-144 carbs.
     
    Huntindog1, Feb 23, 2017
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  18. Scotty Overkill

    Scotty Overkill Administrator

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    I didn't realize how easy it was to pop the limiter caps off of the factory carb, until hdtoolmkr765 mentioned it.....by that point I had already bought the Chinese carb.

    So I'll do a hydrosonic bath on the factory carb and put it in the parts horde for the next time.....
     
    Scotty Overkill, Feb 23, 2017
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  19. hdtoolmkr765

    hdtoolmkr765

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    What saw you running the HDA-144 on?
     
    hdtoolmkr765, Feb 23, 2017
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  20. Mag Craft

    Mag Craft

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    Way to go Scotty. Keep the old carb and put a kit in it. Next time you will have it ready to go.
     
    Mag Craft, Feb 23, 2017
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