saminmn 17 #1 Posted January 18, 2018 (edited) Will a 341 kohler with acr show any compression? mine shows about 10-12 psi. I failed to say its not running. only by starter Edited January 19, 2018 by saminmn Share this post Link to post Share on other sites
KC9KAS 4,741 #2 Posted January 18, 2018 @saminmn I think the engine needs to turn around 600 RPM's before the ACR closes and has "full" compression. 3 Share this post Link to post Share on other sites
pfrederi 17,147 #4 Posted January 18, 2018 Leak down tests are a better indicator of engine health 1 1 Share this post Link to post Share on other sites
953 nut 51,679 #5 Posted January 19, 2018 Even with a properly functioning ACR you should expect to see 50 to 70 PSI of compression with the choke and throttle wide open. I have never done this, but have heard that if you rotate the engine in the opposite direction from the running rotation it will provide an accurate compression reading because the ACR will not kick in. Share this post Link to post Share on other sites
hondagod64 81 #6 Posted January 19, 2018 Leak down test is the best way to test clyinder and valve condition Share this post Link to post Share on other sites
Steve_O 25 #7 Posted January 19, 2018 (edited) Will the ACR function if you spin the crank backwards? Edited January 20, 2018 by Steve_O Spelling Share this post Link to post Share on other sites
953 nut 51,679 #8 Posted January 19, 2018 9 minutes ago, Steve_O said: Will the ACR function if you spin the crack backwards? No it is activated by cyntrifical force in one direction. Kohler ACR.docx Share this post Link to post Share on other sites
Steve_O 25 #9 Posted January 20, 2018 So could you check compression by spinning flywheel backwards? Share this post Link to post Share on other sites
prondzy 3,867 #10 Posted January 24, 2018 (edited) On 1/18/2018 at 6:08 PM, 953 nut said: Even with a properly functioning ACR you should expect to see 50 to 70 PSI of compression with the choke and throttle wide open. I have never done this, but have heard that if you rotate the engine in the opposite direction from the running rotation it will provide an accurate compression reading because the ACR will not kick in. If you run a kohler backwards fast enough to do a compression check you will starve the crank journal of oil, there is a hole in the bottom of the rod cap for this reason when run in the proper direction. I would not try this on my worst enemies engine let alone my own. Do a leak down test if you need to. Can i ask why are you checking this? Edited January 24, 2018 by prondzy 1 Share this post Link to post Share on other sites
953 nut 51,679 #11 Posted January 24, 2018 It only takes a few revaluations to do a compression test, I wasn't advocating a long term run backwards. He has a compression tester and I was letting him know how to get a good reading. Everyone is telling @saminmn do do a leak down test but none of you have had the courtesy to let him know how to do it. Engine Leakdown Tester Build Your Own.pdf Share this post Link to post Share on other sites
saminmn 17 #12 Posted January 24, 2018 OK here is the deal. 16hp 20 over kohler. It was smoking and burning oil (so on the cheap ) I put in 20 over rings and honed the cly wall.Back together it would not fire .static timed it and cleaned the carb no fire ,checked the comp 10-12 psi . Ill make a leak down tester ,well see what happens. Thanks for all help , Ill keep you posted. 1 Share this post Link to post Share on other sites
Shynon 7,435 #13 Posted January 26, 2018 Does it have spark and fuel, I don't think a compression test will make it run. When you disassembled and put rings in it did you line up the marks on the crank and cam? Share this post Link to post Share on other sites
saminmn 17 #14 Posted January 26, 2018 Shynon. I only removed the rod and piston and deglazed the clyinder wall,so timing marks should be ok right? On my way to buy some parts to make a leakdown tester. Share this post Link to post Share on other sites
richmondred01 2,205 #15 Posted January 28, 2018 Did you mic the inside of the middle of the cylinder? Even though it’s 20 over it could have been done years ago and it’s worn. Also I may have not been done right. 1 Share this post Link to post Share on other sites