Author Topic: MS390 - problem after locking crank to remove flywheel and change oil pump? Help.  (Read 268 times)

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Offline Le Maisonniau

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Hi Guys,
I recently created a topic about my 390 not oiling the chain, I thought I had it fixed - but no.
The problem eventually turned out to be the feed pipe with a hole in it, hence the air bubbles I was concerned about mentioned in the topic.

However, I now have a much more serious problem, after obtaining a new pump and feed pipe, I disassembled the fly wheel etc to get at the old pump,  I dont have the special Stihl locking thingy that goes down the spark plug hole so I used the method mentioned of pushing line into the plug hole until it locks   -   and yes it did, this appeared to work fine, it even kept it locked when I torque'd the flywheel back on again.   
Then I had a problem getting the all of line back out of the hole, I pulled about 3-4 feet out and it locked up, I gave it a sharp tug and it 'snapped' I managed to find another end and pull more out till it stuck again,  (I didnt think of turning the crank at that point !!!)  I thought I had it all out so continued re-assembling the 390, then when I tried to start it, it seized up tight.    So took out the plug and looked in the hole and saw a bit more line !! (about a half inch), I took off the flywheel and hand turned the crank, I believe !!! I now have all the line out as I can move the piston up and down at will, it pulls fine on the pull cord too  -   BUT it will not start   :'(-   I am wondering if I have damaged the decompressor or a valve  -

Any suggestions
Cheers   John
Retired in France

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Offline dannyupsolate

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did you check plug gap to make sure line did not close gap.
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Offline Le Maisonniau

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 :)  Plug's OK, it wasn't in at the time.  It is difficult with this m/c to check the spark too, I will see what I can cobble up to see if it is sparking.

But then again, the bit of line left in may have closed up the gap, so thanks, I'll check that.  ::)
Retired in France

Offline Le Maisonniau

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 ;D  Hi Guys,  perhaps I was a bit premature here.
After about 100 pulls on the cord  :o  it coughed, spluttered, died, then next time coughed a bit longer, lots of smoke and then hey - ho, running - not as sweet as it used to  :-\, then let it idle a bit, cranked it up and checked the oil at end of chain and woo-hoo  oil flowing like a good-un.
Probably due to all the turning around etc etc that messed the fuel flow or pushed some debris some place!!

Happy bunny here now - I'll be giving it a good run out tomorrow as we are 'supposed' to be having a bit of summer.
Cheers guys.
Retired in France
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