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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 28073
Experience:  Service manager and technician for all brands of engines with 40 + years of experience.
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I have a Qualcast petrol mower 450 and it went bang and now

Customer Question

I have a Qualcast petrol mower 450 and it went bang and now refuses to start - any ideas??
Submitted: 3 years ago.
Category: Small Engine
Expert:  Curtis B. replied 3 years ago.
Does engine turn too free? With spark plug out,take probe and put into cylinder and feel for the piston, then slowly turn engine to see if piston is moving, if not, the piston has come off the crankshaft and engine is ruined.
Customer: replied 3 years ago.

Engine appears to turn freely but having tried the probe but I cannot turn the engine over with the probe inside

Expert:  Curtis B. replied 3 years ago.
Can you hold finger over the spark plug hole and turn , to see if you have any compression? No compression, will mean valve problem, or piston problem.
Customer: replied 3 years ago.

Not able to do that as starter isa pulley and I am unable to reach the spark plug hole

Customer: replied 3 years ago.

any further suggestions??

Expert:  Curtis B. replied 3 years ago.
With spark plug out, can you turn the blade and reach around to the spark plug hole?
Customer: replied 3 years ago.

Yes I have been able to do that and the piston is moving

Expert:  Curtis B. replied 3 years ago.
Do you have compression?
Customer: replied 3 years ago.

It appears not

Expert:  Curtis B. replied 3 years ago.
No compression, you have likely dropped a valve. This is OHV engine, remove the OHV cover and see if the valves are operating.
Customer: replied 3 years ago.

Thank you for trying but now shall give up now and take it to the dump

Expert:  Curtis B. replied 3 years ago.
Sorry it was not better news!

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