kohler SV600 wont start

It is a Kohler Courage SV600 20HP on a Craftsman Zero Turn Mower. Here is what I have found and done so far. 1) Checked fuel flow after filter but before fuel pump - OK. 2) Checked fuel flow out of fuel pump by adding a piece of hose out of fuel pump - OK. 3) Checked for spark using B&S tester - OK. 4) Changed spark plug with new one. 5) Checked Fuel solenoid by actually seeing shaft go up and down - OK. 6) Checked compression - Got ZERO. Removed valve cover and found exhaust rocker arm completely off valve. Checked push rod to see if it was bent - OK. Re-assembled valve/rocker arm and adjusted both valves after bringing piston up on TDC. Intake .005 Exhaust .007. 7) tried to start engine - nothing. 8) Removed bowl from carb and blew air up main jet. 9) Tried starting again - nothing. 10) Poured a little gas down cylinder didnt start but got backfire. Have not checked flywheel key as yet because I have to remove parts of frame to get blower housing completely off. What is peculiar is that the spark plug is always dry however the carb is damp where the air filter mounts. The bowl did have gas in it whem I removed it. All help will be greatly appreciated.

 

I've got a few questions;

1) Are you sure you were on TDC compression stroke when adjusting the valves ?

2) After you adjusted the valves did you rotate the engine and watch both valves fully open and close in the proper sequence ?

3) have you done a compression test since adjusting the valves ?

 

31Y Tech -- thank you for your response

1) Are you sure you were on TDC compression stroke when adjusting the valves ?

I think so -- I waited for intake valve to close then brought piston up to tdc and adjusted both valves. I then also double checked by watching exhaust valve open all the way and checked intake valve, then watched intake valve open all the way and checked exhaust. Both valves seemed ok. I did not have piston go 1/4 inch past tdc as I would on Briggs because the Kohler manual didnt say so.

2) After you adjusted the valves did you rotate the engine and watch both valves fully open and close in the proper sequence ?

Yes, they seemed to be working ok. What else should I have been looking for.

3) have you done a compression test since adjusting the valves ?

No, I will do that this morning. I figured having a compression release that I would not get a valid reading.

I am going to pull flywheel and check key also this morning. maybe after that pull the head. It is a real pain to pull the flywheel as I have to remove a kind of rollbar that goes across the engine. I was able to lift the blower housing up high enough to get at the valve cover bolts however I could not take the blower housing off.

 

You are some what correct in your thinking, A cylinder leak down test tells all. But, All engines must have ample cranking speed compression in order to start. So, A quick test will tell if you do have enough compression until the release kicks out.

 

Well, I did another compression test and got Zero. I next did a leak down test and got a 48% leakage rate and air was coming out on exhaust side. I also noticed to my amazement that the muffler flange was not connected to the exhaust port. There was about a 1/8 gap between the block and the flange with no gasket to be found. To my way of thinking, I think the engine has a bad exhaust valve. Do you agree ?? This unit has 357 hours on it and the owner told me it has never seen maintenance -- not even an oil change. I would think that the missing muffler to block gasket had something to do with the exhahust valve going bad ??

 

Well, Everything is pointing to the exhaust valve. Maybe burnt from no gasket/Could have stuck at one point due to no maintenance letting the piston slap it (bent), The latter of the two since the rocker had fallen off ?

At any rate a tear-down inspection is needed to go any further....,.

 

Well, I called the owner this afternoon and left a message explaining the findings. I suggested that he come and pick it up and take it elsewhere as I agree that a teardown and inspection is needed. Since this unit has had no maintenance done to it ever, I dont want to get into it. The fact that I found no oil laying in the bottom of the valve cover when I removed it also gave me a bad feeling. If I was younger, I would do it however at my age I would rather stick to repairs and not overhauls.

31YTech -- thank you very much for your help in this. I really appreciated it.

 

I spoke with the shop that fixed this engine. The exhaust valve seat had come out and was keeping the valve open. They did the usual peen job around the valve and put it back together. They were on the fence regarding scrapping it as well.

 

I would have been on the fence as well, But heck.... If the customer has the money and pays in advance for questionable jobs (so their not left after repair), Of coarse without any garrantee.... Why not ?

 

I have very similar problem with same engine this might be the answer for me as well ----removing all other checks

 

sorry - i just saw this today. Yes, the engine finally got running. The shop did the usual repair on the valve seat that came out.