Well I will check for any more melted seals after work tomorrow! You got me really wondering now, if it wasn't so cold out in the garage I would be out there right now checking it all out. Hopefully get some parts ordered tomorrow night, if anything comes out of this it would be me learning a little more about the saw. I am already planning on taking the 028 apart and checking it out, I know my dad bought it around 1980 and he is terrible about maintenance! Could be interesting.
Well, that is the bane about the orange handle plastic Stihl homeowner saws, they have plastic engine housings that can and do melt. Some melting of the case is OK, but more is not. I fixed one melted plastic case oil galley in a 250 with a straw and JB weld once, but I would not recommend doing that. I also fixed a broken fin on a 021 flywheel with super glue, and it is still working. I do not recommend that either, but it worked. The 028 is old school and more in line with a Stihl pro saw, in that it has a split metal engine lower case and thus is less prone to damage when doing things like smoking the clutch. They are built better, with better plastic (white) and they have more pro features. The top ends are easy to work on, but the oil pump and the areas where you are working on with the 029 are a different story.
With 2-stroke saws, use good gas and good premix oil and tune the carb right and you are 90% of the way to a long life with your saw.
The #1 way to cook them is straight gassing them. I did manage to straight gas one of my 361s once, but I caught it right after I noticed the revs going up after refilling it with the gas, and lo... it was the lawn mower gas. I dumped the gas out and popped the spark plug and put in some premix oil and yanked on the starter rope a few times, and then filled it with mixed gas and re-started it. I pulled the muffler later and checked it, and there was no scoring. The pro saws will usually burn a full tank of straight gas or more before scoring badly, whereas the homeowner models will not.
The #2 way to score a saw is running it too lean and/or overheating them, and there are several ways to do that. Running them WOT all the time will overheat them, which is a common problem with chainsaw milling. Running them with the H screw set too lean will score them over time. Running them out of gas all the time will cause them to run lean at the end of the tank of gas. Also tuning them at a higher elevation and then running them at a lower elevation will cause them to run lean (I know people that have blown saw engines that way) . Similar issues come from tuning them with a long bar and then swapping to a shorter bar, which can cause them to over-rev at WOT. And of course if you open up the muffler, you need to richen up the saw, or you will smoke it in a hurry by running it super lean. The EPA has mandated that the carbs on all new saws be set with limiter tabs on them to prevent you from running them richer. As a result the new factory saws are usually set right at the point of running too lean. On any saw that I buy, I pull the limiters, cut the tabs and then reset the limiters back in place, and then tune them richer. The saws run better that way and are less prone to overheating and scoring.
NOTE: if you remove a limiter tab and later have your saw worked on at a shop, they are required by law (EPA) to restore the saw to its original EPA condition, meaning they will replace a modified muffler with an original one, and/or replace any trimmed limiters with new limiter caps. They have to do that by law... just keep that in mind with any saw that you happen to modify. There is no law against you modifying the saw yourself though.
Then there is the running the saw with the brake set issue, which is about 3rd in the reasons that I see the homeowner saws being smoked. Those saws are commonly sold on Ebay, along with straight gassed saws. Crappy gas is a another common cause of engine failure. Low octane (
old or bad) gas will cause flaring and uneven burning and uneven pressure on the piston, and that can cause scoring when the piston tilts a tad on the downstroke. Ethanol gas can cause problems, but usually only when it is exposed to water, and then the gas separates from the ethanol and water. Using pure gas, or E10 with a stabilizer (or premix oil with stabilizer in it) will help prevent that from happening. Using TCW marine premix oil will usually gunk up an air cooled 2-stroke engine, as will using cheap multi-use premix oil. Use a JASO certified premix oil, preferably FC or FD grade. Using too much oil can also gunk up the engine and cause more carbon to build up faster, but usually that is not an issue. I use about a 45:1 gas/oil mix ratio, as there is some evidence that slightly more oil will create a better ring seal, and thus more power in the saw.
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