I'd think the 2 biggest reasons for lean sieze are carb set to lean and a partially clogged carb, make sure to clean it good. Also a pin hole in the fuel line. Steve
MS 170 Tear-down
- Thread starter roostersgt
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I'd think the 2 biggest reasons for lean sieze are carb set to lean and a partially clogged carb, make sure to clean it good. Also a pin hole in the fuel line. Steve
sefh3
Addicted to ArboristSite
That and the seals go bad.
The pictures are fuzzy. Maybe a camera phone pics. If you can't catch your fingernail on the cylinder you should be good. Make sure you apply a thin coat of oil on the cylinder before you install the new piston. I would throw a carb kit on the carb after you have cleaned it good just to make sure it's not dirty.
roostersgt
Addicted to ArboristSite
Crummy camera used for the pics. You should see the crappy felt filter this thing sports. Probably contributed to the damage. Will try to post a picture of it later. Simply junk. Will definately oil the cylinder wall with Tri-Flo before assembly. I really like the Teflon characteristics of that stuff on my bikes.
that was suppossedly the major contributor to the one I fried.
get the optional MS180 filter from your dealer...it's got some brown scotch-pad kinda stuff on the bottom, and is much thicker...been working well on my two...it's a darn tight fit to get the cover on the first time, but that's good IMO
I dunno what the part number is, I just tell em'..."whatever the MS180 filter number is plus one"
for example: if the MS180 std filter number was 8675308 then the optional filter would be 8675309
cheers!
He's not making a phone call he's buying a filter LOL!!!
No, I didn't forget where my 028 ended up. I'm happy to see it has lots of company.
Give me a shout when you have the 170 buttoned up and we can give it a pressure/vacuum test. Besides, I'd love to see what I missed out on.
roostersgt
Addicted to ArboristSite
Can't say enough about the 028AV. Love that saw. It's everything a saw should be. I now keep it at the cabin. Put a $6 Carlton bar Bailey's was closing out on it. That and a Stihl RSC chain. It rips! I'll get with you when I get it back together for the vac/pressure test. I picked up a Harbor Freight brake vac today w/ my 20% off coupon for about $20. Picked up red RTV gasket maker goop and a line reducer. Now I have to find a cheap way to put together a pressure tester. Not paying $87 for the one my dealer uses. He uses a Stens Carb Pressure Guage. They have his at some mower shop on the east coast. The miteyvac is on sale now at NAPA for $72.
Update - just bought Stens knock-off pressure tester on Ebay for $45 w/shipping.
Update - just bought Stens knock-off pressure tester on Ebay for $45 w/shipping.
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roostersgt
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A quick picture of the cool new tools I got yesterday. Vac tester, line reducer, RTV, and some pick type devices to assist with small clips etc... Should be getting new pressure guage in the mail in a couple of days or so, along with the piston, rings and seals.
roostersgt
Addicted to ArboristSite
The new parts from Northwood Saw arrived today. I'll install them as soon as the heat cools down a bit and post the pictures later this evening. Too dang hot to work in the garage. The top of the piston has an "A" on one side and a squiggly box type character on the opposite. Is this significant in how the piston is set up? One side towards the exhaust side or intake side? Does it matter? Thanks.
You want the ring ends that meet to be on the intake side. The exhaust side should be a complete ring with the Arrow ------> pointing to the exhaust.
roostersgt
Addicted to ArboristSite
Thanks. How about a tip on installing the piston clips? I've been fighting them for 20 minutes without any luck. haven't lost one yet, just my patience. They gave me the "G"" shaped ones.
clip
Just install the top of the g first then use a pair of needle noes pliers to rotate the clip in on its self. Should drop in.
Just install the top of the g first then use a pair of needle noes pliers to rotate the clip in on its self. Should drop in.
clips spin on me when I try to use pliers...I'm probably doing it wrong...maybe needle nose vice grips?
I put the top of the G in, then use my thumb and a small common screwdriver to convince it to go in
I put the top of the G in, then use my thumb and a small common screwdriver to convince it to go in
Rookie1
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Some members have filed a groove in the little orange screwdriver to push the clips in. 
roostersgt
Addicted to ArboristSite
Thanks. Got saw back together. Only got one little "rumble", now nothing. Getting spark. Poured small amount of fuel into spark plug hole. Still nothing. Is there some type of timing that can be adjusted?
Seals installed
Gasket material applied.
Engine mounted in chassis
Completed, but won't start.
Seals installed
Gasket material applied.
Engine mounted in chassis
Completed, but won't start.
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Did you take off the coil? If so set it back to .005-.008 thousands. Take the feeler gauge and stick it to the magnet and rotate it into the coil. Unscrew coil and allow it to stick to the feeler gauge, tighten, then pull out the feeler gauge.
roostersgt
Addicted to ArboristSite
Cool, I'll try it with the proper tool. I ried that with credit card. Guess I'll get father-in-laws feeler guages since I can't seem to locate mine.
shawn022
ArboristSite Guru
Credit Card? You need to use a Bussiness Card if youre doing it that way.
roostersgt
Addicted to ArboristSite
Used feeler guage at .007 and still nothing. Sparks well, just doesn't pop. Starting fluid had no effect either. Compression feels strong. I'm stumped.
Setting the gap w/ guage .007
Setting the gap w/ guage .007
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I think you need to make sure you have spark again. I don't think there is a reason that it shouldn't fire if you did everything we have mentioned. Do you have a compression checker? I thought my 025 was okay but it wasn't till I pulled off the muffler. Maybe there is more to this.
