My MS 310 took a dump

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sothere

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Seems to be starving for fuel,I can start it but have to fiddle with the choke to keep it running.
I pulled the filter and blew it out.
It ran fine when I used it last which was right after a muffler mod.
How can stuff happen just sitting in the shop:(
 
After opening the muffler, there will be a lot more airflow through the motor. In order to make it run properly, you also have to increase the amount of fuel so that the fuel-air ratio is the same. Otherwise it will run lean and you will seize the motor due to lack of lubrication.

On the carb there are two adjustment screws marked H and L (high and low). These are for the high speed (full throttle) jet and low speed (idle) jet. I would guess you need to open the H jet about 1/8-1/4 turn and you probably need to open up the L jet slightly as well. Read through this page and ask more questions if you need more clarification.
http://www.madsens1.com/saw carb tune.htm

If the plastic limiter caps on the jet screws prevent you from making the necessary adjustments, you will have to cut off the tabs so you can turn the screws. I use a small pair of diagonal cutters and/or a razor knife.
 
Depending on how big of a hole you carved in the muffler it most likely doesn't idle worth a hoot either . It's just typical of what changes when you relieve the back pressure and is easily cured with a turn of the jets .

Follow that Madsen thing and you'll be in like Flynn .
 
If it was running good after the mod, likely the size of the opening isn't a problem. Al must have missed your saying it was running good at one point. Likely what skwerl advises, the carb is out of adjustment.

Any professional saw user should know how to adjust a carb. I'd recommend a good tach, if you really want to get fine with it....not a must though..
 
OK, but I just figured that his "running good", meant proper idling as well....whatever.

Right about the muffler opening being too big and screwing up the ability to idle, had that happen with a one inch hole in an 036 muffler, my first attempt at a mod. I couldn't get the rpms down low enough to idle, without the engine quitting. I stuck the baffle plate back in and problem fixed.
 
Along the same lines my old 650 Mac has nearly open exhaust .Because of that fact the idle screw has to be set extremely rich ,it puffs black smoke at idle .

However that Tilley H L carb is considerally larger than the one on that Stihl and it's possible to get enough fuel to it so it will idle .

It's possible to get any of them to idle with no muffler but they run lousey ,sluggish and more times than not over run the carb at high speeds .It basically just blows the fuel right out the exhaust .

The design of the pressure can muffler has more to do with preformance than noise surpression . You can ramble on about them for hours but cutting to the chase they are in the simplest of terms just a pressure regulating device .
 
I don't really NEED another saw, but hated to pass up a bargain (if it were a bargain). I figured you guys would know.

I'm not even going to look at it.

Thanks anyway!
 
The 290, 310 and 390 are all the same saw Dennis, just different piston and cylinders, if that helps any. I'm not a fan of them, terribly hard to work on!
A 360 or 361 in the price, jump on it!
 
If it runs good thats a decent price for 310 $200, wonder why $225 is listed too. Like new used ms290 is bringing $200-$250 around me. No case or bar oil thrown in either. Just saw.
 
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