I need some help from the resident small engine guys. I am trying to get a friends Stihl 025 to run and need some direction. This saw has always ran like a champ. I have personally worked with its owner while in use and can verify that, and his personal care of tools is top notch.
Scott let 'Mikey' borrow the saw a few weeks back. "Mikey" returned said saw with no mention of any issues. I asked to borrow it this weekend to cut down a small bradford pear tree. Scott gave me a heads up to check the auto oiler as he thought it might be a little caked up with sawdust from "Mikey"s use.
Once I got the saw home and took a good look at it, its was obviously ran hard to border line abused by "Mikey" I removed the chain and bar, got everything cleaned up and put back together.
Saw will not start. I didn't verify that it ran when I picked it up, just put it in the truck as Scott's stuff has always worked top notch. I check the plug and it is fouled VERY heavily. Checked the tank and the 'fuel' mixture is extremely dark and oily. Air filter is also a mess.
New plug from the local Stihl shop, air filter cleaned, tank cleaned out, pickup screen fuel tube to carb cleaned. New non ethanol 92octane with synthetic 2cyl oil to 50:1 spec per the stihl manual added. Saw will still not start. Muffler removed to inspect for obstructions and screen checked out fine as did the gaskets. All re-installed. New plug removed and inspected for spark while engine turns over via pull cord. Spark is noticeable, however I feel it may be weak. Looking for way to test that.
Air filter housing removed to pull carb out and inspect. I notice that the access tube for the low speed screw and the idle speed screw are moved out of alignment to set screws. Makes me wonder if "mikey" tried dicking with the adjustments.
Carb removed, bottom fuel bowl taken off and flushed with carb cleaner, no gunk or gel noticed. Carb re-installed with access tubes correctly aligned to adjustment screws, filter housing re-installed.
I took the top "low speed" screw to factory setting "all the way tight, then backed off one full rotation. I have no real idea of what the idle speed screw should be set at, any help there would be great.
Saw still will not start, I've tried giving it a little ether and it will not run off of that.
From what I can figure, either there is something messed up in the carb or the idle speed setting is way off. Or I have a spark problem. (with plug removed while turned over fuel mixture sprays out the plug hole).
How do I test to see if I am getting enough spark.
Also wondering about the gas tank vent line. I know it has something to do with overall starting and running, but not sure what it should be at. It is a clear tube with two set screws in it, I believe it to be a one way vent tube.
I have very little small engine experience and have kind of reached an end of what I know to do with it. Any help, pointers or folks that want to find "mikey" and kick his butt with me are welcome.
Never, ever lend out a chain saw. Ever. BTDT. Big mistake.
You are doing all the right things. Check for spark in a dark room by grounding the plug base and pulling the cord. Look for a spark. Or if you are manly enough, hold it (not recommended buuuut....)
2-strokes are very simple; if it's got spark and won't at least cough with ether, then the dufus probably scored the cylinder. Check compression...
In a normally lit room, using a screwdriver grounded to the head and the electrode on the screwdriver I can see spark while engine is turned over. It doesn't seem like a ton of spark, considering its a brand new plug.
Besides plugging spark with my finger/hand and bubba checking for compression I have no real way to "test" compression level.
Try to find out if the "mikey" mixed his own fuel and got too much oil in the mix. That'll choke up a carb PDQ. I had a moron do that to me twice with a little 4hp merc outboard.
I don't know the Stihl ratio but the gas/oil mix for my Husky's (50:1 I believe but that's from memory) is just a very light blue.
Also... gas from flooding can kill a new spark plug.
Try a spritz of ether right into the cylinder via the plug hole. Put the plug back it and rip the cord. If it STILL doesn't even cough, it about has to be compression.
Take the muffler back off and inspect the exaust side of the cylinder and the piston for scoring, If you have any he most likley ran it with the wrong oil or no oil in the gas. also check if the plug is wet when after you try to start it w/ the choke on.
Paul
"I'd rather see a sermon than hear a sermon".... D.A.D.
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Are you sure he didn't lend it to my father? I once watched him mix old motor oil with gas for a 2-stroke. He used my weedeater one time and it came back with the piston skirt in the bottom of the case and what was left of the piston sideways in the cylinder.
I don't know the Stihl ratio but the gas/oil mix for my Husky's (50:1 I believe but that's from memory) is just a very light blue.
Also... gas from flooding can kill a new spark plug.
Try a spritz of ether right into the cylinder via the plug hole. Put the plug back it and rip the cord. If it STILL doesn't even cough, it about has to be compression.
It is 50:1, I downloaded a PDF manual to be sure. I bought premixed fuel from the Home Depot. It is A) 92 octane B) ethanol free C) uses synthetic oil to a 50:1 ratio (you can buy 40:1 as well). I did this as we have not ethanol free gas available, and for small engines I avoid ethanol fuel like the plague!
It would not start with Ether sprayed into the head and the plug quickly installed.
Tomorrow at work I'll pull the muffler/exhaust back off and take a good look at the piston/cylinder for damage.
Take the muffler back off and inspect the exaust side of the cylinder and the piston for scoring, If you have any he most likley ran it with the wrong oil or no oil in the gas. also check if the plug is wet when after you try to start it w/ the choke on.
Yes, when I first pulled the heavily fouled plug it was wet from fuel and every time you would crank it with plug removed it would spray fuel.
I will check it again in the AM to see if it is still spraying. I even removed the fuel screen and just left the pickup tube in the cleaned out tank with fresh fuel.
Not a mechanic but I have used echo products for 30 years... when they are run hard and long with to much oil the exhaust port where the muffler bolts on will clog up with carbon and crap and will not run. You said you checked the muffler and screen did you remove the muffler and check the port for buildup clogging it up? Maybe that will help.
