MS 261 No compression

[Steelz]

My Nephew was using my MS261 yesterday. He said it wouldn’t start. I cleaned it and my Nephew said it still wouldn’t start. The online Manuel said change spark plug after 100 hours of use. I have known idea how many hours since I bought my MS 261 since 2011. I went to the local Stihl dealer. He put in new spark plug. I told him try to start it. He said no compression. They will be closed tomorrow till 7 April. He said it could be piston. But until they take it apart.


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[pioneerguy600]

Badly scored piston smeared onto the cylinder walls will cause compression loss.

 

[Deleted member 117362]

My Nephew was using my MS261 yesterday. He said it wouldn’t start. I cleaned it and my Nephew said it still wouldn’t start. The online Manuel said change spark plug after 100 hours of use. I have known idea how many hours since I bought my MS 261 since 2011. I went to the local Stihl dealer. He put in new spark plug. I told him try to start it. He said no compression. They will be closed tomorrow till 7 April. He said it could be piston. But until they take it apart.


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Pull the muffler and let's see what's in there.

 

[Steelz]

I picked up my MS 261 from the dealer the other day. He said it would be $450+ to rebuild. I said a new one is $600. He said $550. They didn’t take it apart. I asked him what could have been the cause. He said maybe bad fuel oil mix. I told him I use Stihl synthetic oil. Should I buy a new motor?


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[DND 9000]

First a proper evaluation of the damage should be done. You can remove the muffler and have a look if the piston is scored. It would be also good before the complete teardown to do a pressure and vac test. With that you`ll know if you have an air leak. After a closer inspection of the complete situation and the damage you could see what to do.

 

[rupedoggy]

Your Nephew straight gassed it!

 

[irhunter]

I picked up my MS 261 from the dealer the other day. He said it would be $450+ to rebuild. I said a new one is $600. He said $550. They didn’t take it apart. I asked him what could have been the cause. He said maybe bad fuel oil mix. I told him I use Stihl synthetic oil. Should I buy a new motor?


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Gee, that stinks. Here is what I would suggest:

1. Find a different dealer for future purchases. The ol' "This will be crazy expensive, just buy new" trick...that is enough for me to go elsewhere.

2. Ask yourself...do you want to become a saw rebuilder? The work is not difficult...but, it is not for everybody. There are guys on this site who will walk you through it...but, you might not want to mess with it.

3. If you don't want to fix the saw, look around for an experienced non-dealer repair shop or guy. Where I live, there are a couple guys who seem to do good work...for way less than the dealer. Get a quote and report back here.

Roy

 

[John Lyngdal]

I'd first check the decomp valve to see that it was working properly.
Next, I'd purchase a long T-27 torx driver and pull the muffler, and if it's scored, pull the cylinder.
The MS 261 is not as easy to tear down as a 026, but take your time and document where all the little parts came from and you'll be OK.
Even if the piston is trashed, it's likely that the cylinder can be cleaned up and put back into service.
There are many threads of the forum that contain guidance for the removal of aluminum from the cylinder wall.
Personally, I only use muratic acid as a last resort after pitting a 660 cylinder with it.
I use Meteor pistons in my Stihl rebuilds.
And yes, find a new saw dealer that isn't looking to take you for a ride.

 

[CR888]

What 'should' the dealer have quoted for a repair given to do it to Stihl standards he'd need to fit a new oem cylinder kit (not cheap) + labor? All the recommended fixes here are with the use of AM parts and with the presumption the seized straight gas cylinder can be cleaned up. I think the dealer offered sound advice based on the situation. BTW I rarely stick up for Stihl dealers but they are businesses that have to do things properly and stand by any repairs they do.

 

[lone wolf]

I cant help but wonder if it was straight gassed?

 

[irhunter]

What 'should' the dealer have quoted for a repair

I think they should tell the owner the full range of options. They could say, "My boss requires I do a full OEM P&C for $450, but you could find someone to do it using quality OEM for a lot less than that, or it is not too hard to do it yourself."

Now, I understand dealers need to make a buck. But, I also know good dealers do, in fact, describe the options.

Roy

 

[CR888]

So he should recommend going to someone else who can do it cheaper? Quick way to get fired or kill the business IMO. Stihl do repairs to a high standard, it costs money.

 

[jp233]

since the dealer didn't take it apart, either:

• they are too busy, or
• trying to sell an expensive repair
• or a new saw.

just take the saw back, pull the muffler off, and see if the piston is tore up. post pics here if you want. if it is, you know you have to pull the cylinder and fix it, or sell it for parts

 

[John Lyngdal]

A competent Stihl chainsaw mechanic should be able to pull the cylinder, replace the piston, remove the cylinder deposits, install a new piston and reassemble in 60-90 minutes.
$100-150 for labor and the cost of the new piston and base gasket. If the jug is toast, add $150 for the new jug and drop the labor time by 15-30 minutes.
The $450+ repair estimate to $550 for a new replacement saw basically assigns the value of the damaged saw with bar and chain at $100.
I for one would snap up the chance to snag the "hulk" for $150.

 

[pioneerguy600]

A competent Stihl chainsaw mechanic should be able to pull the cylinder, replace the piston, remove the cylinder deposits, install a new piston and reassemble in 60-90 minutes.
$100-150 for labor and the cost of the new piston and base gasket. If the jug is toast, add $150 for the new jug and drop the labor time by 15-30 minutes.
The $450+ repair estimate to $550 for a new replacement saw basically assigns the value of the damaged saw with bar and chain at $100.
I for one would snap up the chance to snag the "hulk" for $150.

If he was working for himself on the side, no dealership I know of will re use a once scored cylinder.

 

[jltrent]

If you are not able to work on yourself sell and buy new. From someone with experience the cylinder might clean up and use a new piston. No compression means either bad gas, air leak, or screwing with the carburetor. You said MS261 so it should not be M-tronic. I say bad gas.