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Was just wondering if anyone has a Kohler Courage with more hours than mine, it's an 18 hp SV540 Courage on a Gravley ZT1844XL Zero Turn, it now has 807 hours, the only thing I've done is change oil and filter every 25 hrs with Penzoil 10W30 Dino oil and air filter once a year, it has a pre-cleaner I wash weekly and re-oil, I adjust valves at end of each season and at that time I re-torque case bolts and replace spark plug, nothing else has been done to it, I am noticing it's not as strong as it once was but only used 1/4 pint between changes. I'm going to run it till it pops to see just how many hrs I can put on it, I already have a 20 hp SV600 to replace it with.

Koehler Courage engines do not have the best reputation out there. I have a Courage 19 2007 engine that I thought would last forever with good maintenance, but it burned the exhaust valve in the head at around 510 hours. I kept everything clean and the MTD mower under cover during the off season, regular oil changes, plug changes, filter changes as per the manual. Now I have no compression as if the plug was out. I have the engine all apart, but cannot find a reason for no compression. Piston looks good, the sleeve looks good, the valves are adjusted .005 intake, .007 exhaust like the manual says. Did the exhaust valve seat go bad? It looks ok, and I lapped the seat and valve, but no joy on compression. What gives?

How did you find out you have no compression?

Real easy - same rotation with the plug out as the plug in. I'm surprised you would ask.

Longshorts said:

Real easy - same rotation with the plug out as the plug in. I'm surprised you would ask.

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just curious, since i don't have any previous knowledge of how much you know about small engines, no offense.
Anyhow, the thing to do would have been a leak down test, as that will tell you where the compression is leaking, piston/cylinder, intake valve, etc.
can you still see crosshatch in the bore/sleeve? is it shiny smooth?

Been working on engines since I was 13, not so much on small engines. I'd rather have a Briggs cast iron block than an aluminum block. Then the valves would be in the block, not the head (sohv limits life of the engine, needs special oils, and so on). Pressure relief valve looked OK, functional, crosshatch somewhat faint in cylinder, but visible, piston rings not frozen to piston, not broken either. Don't need a compression gauge to tell there is no compression, a finger in the plug hole would tell me that. The engine has bright spark, fuel, air. No leaks in the gaskets either, I checked. I'm goung to get an adapter for my compressor to fit the plug hole and see where the air leaks out - should have done that before I took everything apart. No, you didn't offend me.
My Uncle taught me everything I know up to 2008, I've kept up on the newer stuff myself, just not much on small engines. Plastic gears in the timing system/valve system? Unheard of! Junk, but looks unworn. Maybe find a blown Courage 19 for spare parts and compare.

Scrubcadet10 said:

just curious, since i don't have any previous knowledge of how much you know about small engines, no offense.
Anyhow, the thing to do would have been a leak down test, as that will tell you where the compression is leaking, piston/cylinder, intake valve, etc.
can you still see crosshatch in the bore/sleeve? is it shiny smooth?

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I agree a leak down test will tell where the leak is