Stihl 039 Rebuild PROBLEMS... HELP...

[Burl Hunter]

Stihl 039 with a 46mm engine - I know I installed the wrong engine and basically have a 290, but I have to live with it now. I can't dump anymore money into it. I bought it cheap, but have completely tore it down not knowing anything about chainsaws and have had a blast learning how to rebuild it. I finally got it together, but there is just one problem. : ) I refuse to take it to the dealer.

Problem: keeps stalling after 20 seconds to 2 minutes of idling. [/U][/B]

Yes! I have replaced the fuel line and filter, made sure I had Stihl 2 stroke oil with 50:1 mix, checked the spark plug gap, checked the flywheel to ignition coil gap, changed the spark plug, installed a new air filter, and so much more.

I am not sure what the compression is. That could be a problem. The piston doesn't look scored even though I have reved the heck out of it for 10-15 second bursts.

Here is what I am thinking - Possible Problems:
1. Might be the impulse line, but that is new and I will replace it again.
2. I accidentally downgraded to a 46mm engine. Do I need any carb modifications to make this thing idle consistently in my 039.
3. When I sealed the upper to lower parts of the cylinder, I used the red Stuff from Stihl and now see small parts of it in the spark plug and spark arrester. NOT GOOD I assume???

Please help.

 

[twochains]

You should hit up the chainsaw forum, might get more attention there. Is the cylinder new or used? Is the piston new or used? Just taking a wild guess here but, sounds like an "egg shaped" cylinder with a new piston stuck in in it. 20 sec. to 2 min. voluntary shut off sounds like piston seizure to me. You say it shuts off, how long after this happens can you re start? If not until the motor cools a bit...that sounds like seizure.

Try the chainsaw forum though

 

[Stihlofadeal64]

It is already in the chainsaw forum, with replies. The OP posted it in several areas here on the site.
He needs to reply to the chainsaw forum thread so we can help him get the problem resolve (no malice or anger here...he probably just does not know and is trying to get an answer for his problem --which is understandable.) If he reads this...he may want to ask the moderators to delete all the threads but the chainsaw thread -- it will be less confusing for those ready to help.
Have a great day!