MS170 quit wont start

[bud605]

MS170 quit while using,now wont restart. Its got spark, checked that out. Changed gas out, even though it ran though two and a half tanks of gas that was in it. Weed eater and MS310 run fine off the gas as well. Its sat a couple days, and tried as well so dont believe its a flooded issue, like i said earlier was in use when it died, now wont restart. Air filter is realitve clean... cant see any broken/unattached wires. Tried a shot of either and still no fire.... Like i said, i've pulled the spark plug and its got spark... At a loss, dont know what to do next beside taketo a small engine place...

 

[bertsmobile1]

Does it have a spark ?
If it was under heavy load at the time you could have fouled or whiskered the plug

 

[bud605]

Does it have a spark ?
If it was under heavy load at the time you could have fouled or whiskered the plug

What do you mean wiskered the plug? Same thing as fouled? Ill swing in and get a new plug, and see if that helps...

 

[bertsmobile1]

Different mechanism, same net result , the voltage leaks away and no spark occurs .

 

[StarTech]

First check the muffler spark arrester screen to see if it is clogged. Stihl equipment are known for clogging these. May not be present if you have a cat muffler.

Also when you pulled the plug was it heavily greyed (aluminum transfer)? If so most likely you have cylinder damage. To verify pull the muffler and take a look at the cylinder for scoring.

 

[bud605]

Does it have a spark ?
If it was under heavy load at the time you could have fouled or whiskered the plug

What do you mean wiskered the plug? Same thing as fouled? Ill swing in and get a new plug, and see if that helps...

Yes the old plug had spark. Got a new plug today came home from work installed new plug. Pulled it and fired, no start. Clicked up off full choke, fired and ran, shortly! Pulled couple more times got it running! Would not have thought of the spark plug! I dont think Ive put more than 3 new plugs in my MS310 in 15+/- years... and only because I figured it was time too... Thanks for the suggestion!

 

[bertsmobile1]

Moder fuels are not like petrol & very conductive at compression pressures
BEcause of lead emission regulations the insulator noses are no longer glazed so once they start to track the only way to clean them is to burn the deposits off.
Get it nice & hot then change back to the old plug
DO NOT OVERTIGHTEN IT remember HOT hole COLD plug is a shrink fit so just finger tight
Chances are the old plug will fire & clean itself
In future when using it if you can hear the engine slowing down don't force the saw, sharpen the blade .

 

[StarTech]

Dull chains is something I see a lot. Many homeowner have destroyed their saw bars by forcing the saws to cut. I have replaced nearly new bars because of this as get burned. The saw users do need to learn how to sharpen their chains as file guides are readily available. A properly sharpen chain will self feed just by the weight of the saw in the cut. If you are having press down on the bar then the chain is dull. A got those techs that sharpen chains never touch the depth gauges either. These must be checked and filed to spec too everytime a chain is sharpen.

I just had taken pictures of the last poorly sharpen chain. The owner destroyed it which was the reason he had the saw in my shop. I made up a new loop and sold him a file guide with the correct file size. He was trying to use a flat file to sharpen the cutters as he wanted square cut cutters. Well this takes a triangle file especially designed for this. Once he found out the cost of the file he gladly went back the standard round files.

I had hand sharpen chains for 40 yrs but lately due to new harden cutters I started a chain grinder. I got tired of the blisters. It is fully adjustable unlike that Harbor Freight piece of junk that you only adjust one angle on. Plus after about a year it get very sloppy. The only decent thing was the grinding wheel.

I used one and when I got my Oregon chain grinder I completely disassemble the HFT grinder before putting in the trash. I just didn't want someone else getting a piece of junk and screw up their chains.

And as for the spark plug, new plugs are hand tighten and then turned approximately 1/2 turn further by wrench to get the new gasket seated. If not the new plug will loosen due the crush gasket getting crushed by the heat expansion of the cylinder. I got saws and other equipment in the shop because of this. Another reason to install the plug by hand is they can be easily cross threaded if install by tools.

 

[bertsmobile1]

The loose plug was to see if the old one would self clean in a hot engine
I should have mentioned to remove the replace properly when both are cold
I have 2 Jolly grinders
One set up for the depth stops & the other for sharpening using the diamond wheels
It does not do as good a job as hand filing but for $ 15 there is a limit of what I will do.
Bought a cheap 12" bench grinder that will get set up for bar grinding.
I don't file most bars because it is cheaper to replace them unless they are genuine Oregon bars but most of what is branded Oregon down here is fake .
And yes you can always see the difference between a mans saw and womans saw but the presence or absence of an undercut in the bar near the spikes .

 

[StarTech]

Well with my Oregon grinder I am using the standard stones that comes with it. When they are properly shaped they do just as good as hand sharping as long you don't get too aggressive and burn the cutters. The chains are just as sharp as new ones. I do however need to add a reversing switch setup to it as one side tends to leave burrs on the cutters if I don't remove them while sharping the chains. If I did more chains I would probably get a couple more units so I don't need to change the stones.

I just don't see need for diamond or CBN wheels.

As for the bars most are too far gone by the time they get to my shop.