Originally Posted by lawnsaspire
This is a continuation of another thread I started 2 or 3 months ago about the oil darkening quickly on my 24 hp Kawi Scag V-Ride. Some of you who also own this mower have stated having the same issue. As my season is over I took the mower into the dealer. They said that bad gas had created carbon build-up on one of the valves creating blow-by that has ruined some of the gaskets but not the engine. They said the engine warranty does not cover bad gas (of course) It'll be about $300 in repairs and parts. I'm not a mechanic beyond routine maintenance, so I have to take their word that this is the case. If this is true, which I don't have any reason to believe it's not, you guys who have stated similar issues with the engine on the V-Ride ought to get it checked out. THey said continuing to run the engine like this would have resulted in much more damage. I don't know how they know that bad fuel caused this, but right now I don't have any other choice but to trust them and pay for repairs. Any thoughts?
Just one :That is utter B.S. !!
1. bad gas wont cause "carbon" buildup on the valves, varnish/gum deposits yes, but not carbon.
2. a bad valve ( regardless of why its bad) won't cause "blowby".
Blow-by is caused by worn piston rings or a worn cylinder bore, letting combustion gasses BLOW BY the rings and over pressurizing the crankcase, which can contaminate the oil, tax the breather system, force oil past the rings into the combustion chamber etc.
3. A blown head gasket can cause the same symptons, but is not the same as blow-by.
What gaskets exactly
did it ruin?
I know Kaw. recommends decarbonizing the heads/pistons at a specified hour, that may be what he was talkin' about.
air cooled mower engines use/burn oil, which in turn, causes carbon build-up, that's the nature of the beast.