550 EX breather

bertsmobile1

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Back to this 9p702 0127-11 engine which was giving me grief
Do any of you have problems with the breather reed valve ?
Does any one know how sensative it is ?
should it work when slowly rotating the engine by rotating the blade by hand or does it need substantially more inertia

Point being the mower I just sent back had a new air filter fitted by the owner last year.
When I tried to start it today i would not run with the filter on .
The filter was fairly clean but did have a lot of oil & fuel in it so I am starting to think that the reed valve has failed or is stuck open.
Same story that would have been more labour to check it than the customer wanted to pay for but a new plug & filter annually is fine
 

ILENGINE

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Bert let me do some checking later today. I have a EXI625 that came in with the air filter soaked in oil. Oil all over the deck, and no oil in the engine that when refilled with oil was spitting oil out the breather. Engine got put aside due to the possibility that it was ran without oil.
 

bertsmobile1

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The mower is gone now but as I expect to see a lot more of these engines in the future it would be good to know.
A lot of the old bangers I ride on the weekend had reed valves but a lot of them do not work at kickstart speeds.
It would be good to know because it is a big job to get to the reed valve on these engines.
 

ILENGINE

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OK Bert tore the engine down to inspect the reed valve. The reed was not broken or damaged but next to the read port is a small welch plug with a hole in it about the size of a tag wire for a drain back hole. I could easily see that hole getting plugged with debris and preventing the oil from draining back and spitting out into the air filter. Also there doesn't appear to be a filtering mesh or at least in the one that I took apart.
 

bertsmobile1

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Thanks for that.
The top of the engine was quite damp so the said hole might have be blocked
What I really would like to know is
If you put your finger over the carb end of the breather tube and rotate the engine by hand, does it blow & suck or just blow
ie does the reed valve seal at low crankcase speeds .
Once I know this I can add it to the standard tests for these engines.
Pulling the flywheel & top cover off to check the breather will nearly double the service time on these engines.
Not being a B & S authorised technician natually I have no access to the Power Portal so updates for this engine not in the small OHV manual are not available to me.
 

ILENGINE

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While rotating by hand I get a good puff type blow on the piston down stroke and a slight vacuum on the piston upstroke.
 

bertsmobile1

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Thanks Rivets
The one that just left blew & sucked about evenly so safe to assume it was not working properly
 
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