Gas Man 19 #1 Posted December 20, 2019 Why does the Crank Case Vent tube have so much pressure on my KT17? It feels like it is connected to an air pump!!! My first thought is that the engine is worn out and it has severe "Blow By." While I have only put a couple hours on it since I got it out of the barn, it does not smoke much at all, but after it heats up it runs real rich and occasionally on 1 cylinder. I disconnected the breather from the air cleaner and it runs MUCH better. I ran a compression check on it a while back and the numbers were lowerer than I had hoped for, although I can't remember them. I want to think it was around 90 ish. Share this post Link to post Share on other sites
Ed Kennell 42,016 #2 Posted December 20, 2019 Check the compression again. May be a sticky valve not closing. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,488 #3 Posted December 20, 2019 Sounds like you may have excess fuel in the engine oil. Make sure the oil level has not increased from a leaking fuel pump. After an engine is running the crankcase should be under a vacuum if there are no air leaks like the at the dipstick or the crankcase vent is not closing. Air should come out there but not go in if the check valve is sealing. Garry Share this post Link to post Share on other sites
Gas Man 19 #4 Posted December 21, 2019 21 hours ago, gwest_ca said: Sounds like you may have excess fuel in the engine oil. Make sure the oil level has not increased from a leaking fuel pump. After an engine is running the crankcase should be under a vacuum if there are no air leaks like the at the dipstick or the crankcase vent is not closing. Air should come out there but not go in if the check valve is sealing. Garry So this engine has a Check valve , otherwise known as a PCV valve? I will have to Check that out. Pun Intended - - Ha Ha! I know there is no fuel in the oil as the oil level never changes. You say that air should come OUT there but not go in...Hmmm If it's supposed to run under a vacuum, I'm going to have to lean toward a bad motor (blow by) 23 hours ago, Ed Kennell said: Check the compression again. May be a sticky valve not closing. 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,488 #5 Posted December 21, 2019 From this service manual. Breather starts on pages 12 and 13 and the illustration on page 63 Garry Share this post Link to post Share on other sites
