How much is to much compression?


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Old 05-28-14, 06:38 AM
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How much is to much compression?

I've read quite a few times on here that the best way to check compression is with a leak down tester, unfortunately I don't have one at this time. My question is how much compression is to much on a small engine on a riding lawn mower. The one that I am working on now is a 16hp Briggs Vanguard 303777-1114-E1 that's reading 160 psi on one cylinder and 170 psi on the other, which seems to be a lot higher than I've seen.
 
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Old 05-28-14, 09:45 AM
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That's a high reading... are you having problems starting it? Have the valves been adjusted?
 
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Old 05-28-14, 09:52 AM
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It starts pretty normal actually. The only issue is when pushing the throttle from idle to full throttle there's just a bit of black smoke from the exhaust just for a second.
 
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Old 05-28-14, 09:58 AM
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That's fairly normal for that engine. I'd adjust the valves and use it. Those engines are top of the line... you won't find much anything better.
 
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Old 05-28-14, 10:02 AM
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Thanks for the input. What are the basic steps to adjusting the valves?
 
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Old 05-28-14, 10:06 AM
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Turn the engine to TDC on the compression stroke, then 1/4" past tdc and set the valves on that cylinder to .005" with a feeler gauge. Repeat with the other cylinder as well.
 
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Old 05-28-14, 10:37 AM
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Thanks for the information and help
 
 

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