have a new mower with a 675exi....very little use never ran low on oil yet compression is low and now doesnt start,,,,l10 psi on compression guage, sp

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frankfix

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have a new mower with a 675exi....very little use never ran low on oil yet compression is low and now doesnt start,,,only 10 psi on compression guage, spark and fuel r good, valves r closing NOT sticking open cause rocker arms valve lash in spec.help!
 
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Most engines now have compression releases which reduce compression at cranking rpms. Beside that, 110 psi is enough for an engine to start and run.

If it's still under warranty, let them fix it.
 
cpurvis said:
Most engines now have compression releases which reduce compression at cranking rpms. Beside that, 110 psi is enough for an engine to start and run.

If it's still under warranty, let them fix it.
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thx but i miswrote only 10psi compression thx
 
Double check the valve lash.
Should be around 0.005" both sides
If it is smaller the valves are held open for too long and you don't have enough compression to start.
Compression tests are meaning less because of the automatic decompression.
 
Compression is about meaningless on newer engines. I performed a leakdown test on a generator several months back that had less than 5% bypass but only showed 5 psi on the gauge. Engine ran fine after cleaning the exhaust screen. I would be looking into fuel quality and try putting a small amount of FRESH fuel into the intake and see if it pops off or not.
 
ILENGINE said:
Compression is about meaningless on newer engines. I performed a leakdown test on a generator several months back that had less than 5% bypass but only showed 5 psi on the gauge. Engine ran fine after cleaning the exhaust screen. I would be looking into fuel quality and try putting a small amount of FRESH fuel into the intake and see if it pops off or not.
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interesting..... i squirt fuel in carb right after i check the oil on all non starters for pops but the only firing pops i heard on this one r like backfires in the exhaust as if the cam tiring is way off or the exhaust valve is sticking open.....i removed the rocker arms and both valves bounce right back as normal, valve lash within spec
 
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