New jug on MS170?

[Tostuk]

So it's my first time trying to resurrect a chainsaw. Bought this fairly new MS170 off a guy that had straight gas ran in it by accident, I hope the cylinder is reusable because I'm not really looking to pay a lot for the parts. I'll use it for parts in that case.

The pics are here:
From the images it doesn't look so good but the surface is really smooth. There's just 1 minor scratch/aluminium deposit that I could barely feel with my finger which is on the intake side and above the intake. From the picture I can see some aluminium below the intake also but with the naked eye I couldn't see it.

If it's reusable then would it be more of a temporary fix or would run for a good while?

 

[Bob Hedgecutter]

Only way to find out is to start cleaning off the transfer, see what you have left.
If there is nothing gone through the interior coating, no rough grooves you can catch a fingernail on, you might be good to go. You want to clean that big chunk of carbon off the exhaust post while you are at it, maybe polish up the port surfaces a bit so the carbon does not build up again while you are in there.
I had a 170 I basically wore out. I was lucky enough to find someone unlucky that had a low hour 180 they finished cutting with, sat the saw down, had a bite to eat and then decide to shift their trailer closer to the wood pile and backed over the saw that was waiting on the ground! Busted up the plastics bad, not worth replacement/repair, but the motor was okay- so my 170 became an OEM 180.
That is about the only way repairing one of these becomes economic if you want to use OEM parts.

There are cheap AM kits out there for these, are they any good? Possibly not great, but they will make something that will run for very little cash outlay- depends if that is a gamble you are willing to take.
Thing is, these are fairly cheap saws new and OEM parts are expensive, a new piston & rings might set you back more than the secondhand saw is worth on the open market.

 

[Jasonrkba]

That cylinder will probably clean up enough to run with a new piston. I've used AM pistons on these in the past with good success. How much do you like the saw and are you looking for a project. I think its worth tring, just see how it looks after cleaning up the cylinder as stated above. Do the muffler and carb mods when your done.

 

[Jasonrkba]

Here is an example of the worst cylinder I've fixed. It was from a Pioneer 41 that was straight gassed. I couldn't find a replacement. It has a little red barn piston in it now and runs very strong. We toss a lot of cylinders that will work because replacements are available but if money is a issue you do what you have to.

 

[Tostuk]

Only way to find out is to start cleaning off the transfer, see what you have left.
If there is nothing gone through the interior coating, no rough grooves you can catch a fingernail on, you might be good to go. You want to clean that big chunk of carbon off the exhaust post while you are at it, maybe polish up the port surfaces a bit so the carbon does not build up again while you are in there.

That cylinder will probably clean up enough to run with a new piston. I've used AM pistons on these in the past with good success. How much do you like the saw and are you looking for a project. I think its worth tring, just see how it looks after cleaning up the cylinder as stated above. Do the muffler and carb mods when your done.

Alright I managed to get my hands on some muriatic acid and tried to clean the aluminum off. I'd say that it's a bit worse now than before as it seems like the aluminium deposits had covered up the rougher spots making it pretty smooth. However I have no clue whether the rough spots are fine or not. They seem to be so minor that I basically can't feel them with my fingers I only notice them when I run my fingernail over it.
I think I'll try putting a new piston in.

 

[Jasonrkba]

Take some medium scotch brite to it and then you will know how much sanding you need to do.

 

[Jasonrkba]

And the sanding process can be extremely time consuming and hard on the arthritis.

 

[Tostuk]

So I will need to sand all the rougher spots? I tried some sanding with a 500 grit paper but it didn't seem to do much indeed. Also how thick is the nikasil plating?

 

[Bob Hedgecutter]

So I will need to sand all the rougher spots? I tried some sanding with a 500 grit paper but it didn't seem to do much indeed. Also how thick is the nikasil plating?

Yep, sanding can be easier than using acid for someone that has not tried to clean a cylinder up before- 500 might not bite so well for a start, try 180 grit and work your way up through paper grades until you remove ALL transfer, then check for wear through the cylinder coating.
Hand sanding and checking often- you will be hard pressed to sand through the coating. Using a mechanical sander can lead to problems of going too far.
Use the search feature of the forums, there are bound to be tutorials about cleaning up cylinders with photos that will explain it better, but the cylinder needs to be cleaned fully before you re use it.