046 Magnum- beginning of the end?

[steelhead kid]

Need some advice here guys. Is a big bore kit alwas a good thing?

Anyone ever try a NOS brand big bore kit on ebay?

I have an 046 magnum that will not idle. The Stihl dealer told me today that the piston and cylinder are scored because of what he saw when he pulled the muffler and looked at the exhaust. He did not try to fire it. He said I can continue to run it but at the risk of destroying the bottum end . I knew it was slightly scored when I got it 6-7 years ago, guess it got worse.


It was $400+ to repair with OEM. But after market big bores on Ebay are around $100. If I do it myself thats not bad. Anything in particular I should know if I attempt this fix?

 

[blsnelling]

If you choose to go with a BB kit, do not buy it off eBay. Buy it from Baileys, as they will stand behind their product 100%.

 

[steelhead kid]

Just the guy I was hoping would reply. Thanks Mr. Snelling. Does a BB kit make the saw more susceptible to heat damage? It is an older saw.

 

[blsnelling]

Just the guy I was hoping would reply. Thanks Mr. Snelling. Does a BB kit make the saw more susceptible to heat damage? It is an older saw.

You won't have any issues with heat running a BB kit. You should pull the cylinder and check it out first though. You may only need a new Caber piston for $40.

 

[nmurph]

no..... and you need to pressure test you saw to find out why it scored the cylinder. either it has an air leak or was straight-gassed at some point and has gotten worse over time.
&+1 on baileys vs ebay for you BB kit.

 

[steelhead kid]

Yeah, I thougt he came to the conclusion a little quick. he said the scoring was from overworking the saw, or pushing on a dull chain. I don't do this. I know I havent straight gassed it , but like I said they noticed slight scoring during a tune up when i bougt it used 6-7 years ago.guess it got worse over time. I'll ask them about the pressure test when I pick it up today.

 

[steelhead kid]

What is a caber piston? why would need that instead of the one in the BB kit?

Anything else to consider, cost wise?

 

[mtngun]

What Brad meant is that the jug may be re-usable, only requiring a new aftermarket piston to get it running again. You won't know until you pull it apart.

 

[bcorradi]

I think he was meaning a episan or meteor piston. The link below is a site sponsor carries them. 046 Episan Piston

 

[blsnelling]

Sorry, I meant to say Meteor piston, LINK. They use Caber rings.

 

[steelhead kid]

How do I know what to look for when inspecting it- how much scoring can be tolerated on the jug/cylinder, and how much on the piston?

 

[oscar4883]

No scoring on the piston is acceptable. They are pretty affordable. The cylinder may still be usable depending on where the scoring is. Best bet is to post pics of the piston from the exhaust port. Then clean the saw well and get the cylinder off to see what you are working with and if it can be cleaned up. Cleaning the saw is a VERY important part of the disassembly process.

 

[nmurph]

scoring below the exhaust port is not critical. what you don't want is aluminum deposits on the bore wall. even a little scoring on the piston is ok if you change the rings.

 

[steelhead kid]

The dealer made his assessment from pulling the muffler and looking in the exhaust port. I hope he is wrong about the cylinder.

When i pick it up today , I'll post here again.

 

[oscar4883]

nmurph is correct that some scoing MAY be acceptable on a piston. However they are pretty cheap and will give you the knowledge that you are good to go. If you pull the spark plug you can get an ok look the the cylinder wall around the exhaust. That will give you a better idea. The Baileys NWP BB kit is very nice. I have one on my 460 and it has a zillion tanks through it now with now issues.

 

[nmurph]

oscar, i agree with you also. pistons are cheap enough that i usually just replace them when i am in that far.

 

[steelhead kid]

News from the shop:

I had it pressure tested. It has a leaky camshaft seal. This is the culprit of the scoring.

Is this a difficult fix?

 

[pioneerguy600]

News from the shop:

I had it pressure tested. It has a leaky camshaft seal. This is the culprit of the scoring.

Is this a difficult fix?

Most likely a leaky crank seal, no camshaft, and they are relatively easy to change out.
Pioneerguy600

 

[steelhead kid]

Yeah I meant crank seal. Is it worth paying sixteyfour dollars to fix, the part is 7 bucks? I wouldn't mind doing it myself and do a BB kit. But none of this I have ever done before. Any way to get installation instructions?

 

[tlandrum]

the chainsaw forum on as is like having your own mechanic,just do it. well be here to help