Take a look at piston! Before throwing parts in you might not need.........
Stihl 028 AV
- Thread starter coldfrigman
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Take a look at piston! Before throwing parts in you might not need.........
coldfrigman
ArboristSite Lurker
Ok, so I took a better look at the piston, through the plug hole in the front, and muffler opening in the rear. The piston appears to look good, with little if any discoloration or marring. The cylinder did appear to have a build up of either oil residue or carbon, but looked blackish in color. I did notice oil now on the spark plug, and in the muffler opening, etc. I checked the compression and came up with 110 psi. Does it make sense to pull the piston and put a new set of rings in it? Is there anyway a bad coil could be the problem, with it bogging out after a while on fast idle?
I went through a steel tank points ignition 028 for a friend that sounds like yours. It also had 110psi compression. The piston showed signs if blow by but the cylinder looked good. I broke the glaze in the cylinder with some scotch right and put a Meteor piston and rings in it. I also replaced everything rubber on the saw. Compression is up to 150psi and the saw is ready for another 40 years of work.
coldfrigman
ArboristSite Lurker
so in your opinion buy a new piston with rings, and clean up the cylinder? you wouldn't have the link to where to buy the piston do you?
I bought a Meteor piston from eBay. Some of the sponsors at the top of the AS home page should have them too.
It's important that you measure the piston in your saw before ordering to be sure you buy the correct size for your cylinder. Stihl used 42, 44 and 46mm pistons through different models. The 44 and 46mm are the ones I run into most often.
It's important that you measure the piston in your saw before ordering to be sure you buy the correct size for your cylinder. Stihl used 42, 44 and 46mm pistons through different models. The 44 and 46mm are the ones I run into most often.
coldfrigman
ArboristSite Lurker
Thanks for the advice. Next step take the motor apart, and see what I need.
coldfrigman
ArboristSite Lurker
Bob, I have my new Meteor piston. Before assembly should you lubricate the inside cylinder before assembly or after?
Put a little 2 stroke oil on your finfer, and lubricate the cylinder before you put it over the piston.
What Totembear said
If you're going through the trouble of replacing the piston I'd do the seals while you're at it.
coldfrigman
ArboristSite Lurker
new piston, same result with pulsing and dogging out. Looks like I am going to make one last attempt and order a Walpro brand carb kit, and rebuild the old carb again using name brand parts. It seems to run better even now with the old carb, instead of the tilletson. Would anyone know, if the manual says 1 1/4 turns out from bottom on the low idle mixture is a starting point, if it is set to 3/4 only turns out and runs much better, will this harm the machine? I know I am cutting down on fuel, making it leaner.
Dont get so caught up in the numbers, they are only for reference and starting point. The thing is, if you can hear it 4 stroking out of the wood and it cleans up in the wood, you're good.
I had a 028 that ran the same way and re ringed it and did base gasket delete which fixed the Fixed the issue.
Take it to a stihl dealer and have them perform a leak test on it. Some of them will do it pretty cheap. They will tell you where the leak is at, based off that you will know how bad it will be to fix.
coldfrigman
ArboristSite Lurker
Two questions. What is "base gasket delete"? Do you mean where top of cylinder meets the bottom half? Also, what other seals to replace are you referring to ?
On either side of the crank shaft there are oil seals. They have a rubber lip that goes bad and creates a vac leak. This is often neglected and fairly easy and cheap to replace. There is no way I would do a piston and not the seals with it.
yes he is refering to the cylinder gasket. There are mixed opinions about doing it so do your research. I'm not a fan but that is just my opinion.
yes he is refering to the cylinder gasket. There are mixed opinions about doing it so do your research. I'm not a fan but that is just my opinion.
coldfrigman
ArboristSite Lurker
Jason, Interesting, since I do get a good amount of oil coming out, thought it was the chain oiler. Are these easy to replace? What actually has to be dismantled to do this? Do I have to remove the piston and top end cylinder again? Lastly would you have a link on how this is done, and where to buy them? Thanks for your input and help.
It's not a complete disassemble but you do have to remove some of the exterior parts. Its been a few years since i did them on a 028 but I do remember there are a couple different variants in the 028. Try YouTube. There are a couple good videos to walk you through it. If they are bad what you will most likely notice is that it is not possible to tune it. And if you keep trying it will toast your new piston.
coldfrigman
ArboristSite Lurker
Ok, I checked out YouTube, and that should help me. I assume you bought aftermarket seals and not Stihl. Don't see them listed, but maybe the dealer.
I can't remember what brand I used exactly but they where aftermarket.
