Older BR400 blower problem

[trooper1954]

Hi Guys,
Don't really know where to start with this....Blower went into repair shop, and it was discovered that the flywheel needed replacing., that was why it kept breaking keys.That was done and a new woodruff key installed....$200!!!....and it took 5 weeks due to waiting on parts.
I took it home and put mix in it with stabilizer for the winter. pulled to start and guess what... woodruff key broke straight away!!!!
Does anyone have any idea what is causing this? It was difficult to make that first pull...almost as if something was seized.
Of course, as soon as I'm able it will be going back to the shop but I'm not confident it won't cost me another wack of $$.
Any help or advise appreciated.

 

[Fish]

Take it back, they own the problem.

They may have improperly tightened it down at the shop, and they should take care of it.

 

[trooper1954]

My thoughts exactly Fish,,,but we'll see if they agree!

 

[trooper1954]

Any idea as to what could be causing this continuing issue besides the flywheel/crankshaft/woodruff key problem?

 

[Fish]

Here is the generic bulletin on it.

 

[trooper1954]

Thanks Fish....but when you have a certified tech fixing the thing you'd assume he should know this, and I presume he followed the outline when he replaced the flywheel and woodruff key

 

[bertsmobile1]

Not if they are just a parts swapper.
The crank is probably damaged the same as what happens when a flywheel key shears .
And similarly it probably need to be lapped to the flywheel to repair the damage that is preventing the tapers locking together .

 

[trooper1954]

bertsmobile1.....you're right! Shop was not happy to see the blower returned this morning....told my wife that now probably needs a crankshaft and it's probably not worth it on such an old machine!! I wish we had techs that could fix things instead o being just parts replacers
Perhaps I should try and find a BR 400 for sale that I could use for parts, or does anyone think perhaps a machine shop could salvage the crank in some way? I know Stihl wants $250 for a new one!!
I'll review your much earlier post about lapping to see if I feel confident enough to give it a shot.
Any comments appreciated.

 

[Fish]

Was this a Stihl dealer?

 

[bertsmobile1]

bertsmobile1.....you're right! Shop was not happy to see the blower returned this morning....told my wife that now probably needs a crankshaft and it's probably not worth it on such an old machine!! I wish we had techs that could fix things instead o being just parts replacers
Perhaps I should try and find a BR 400 for sale that I could use for parts, or does anyone think perhaps a machine shop could salvage the crank in some way? I know Stihl wants $250 for a new one!!
I'll review your much earlier post about lapping to see if I feel confident enough to give it a shot.
Any comments appreciated.

The key is just there to locate the flywheel so the magnet is in the correct position with respect to the piston
Take the flywheel off and very carefully file the edged of the keyway, they do not need to be sharp just so long as the key is a tight fit
Now without the key apply liberal amounts of Brasso on the shaft and lap the flywheel by rotating it back & forth
Lift slightly every few seconds & regularly dab more Brasso on the shaft .
As the surfaces get closer to each other you will feel them starting to stick together .
Clean both surfaces vey well and do a test by pushing the flywheel on with your thumbs
IT should lock and be quite hard to pull apart when they two surfaces match.