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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 28638
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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Engine starts but has no power whatever. JD says I need a

Customer Question

Engine starts but has no power whatever. JD says I need a new engine. Before I do that I need to know a few things. They said the compression should be 130 psi. What is the compression ratio? I have an airplane with 10.5:1 ratio and 75 psi compression is very good.
JA: I'll do all I can to help. Is there anything else the Small Engine Technician should be aware of?
Customer: On a previous situation, I was advised by another JD tech that it had 'dropped a valve' which they fixed...rear cylinder not working at all...engine blowing smoke...I was thinking an ignition problem. A bit skeptical that this engine would need a rebuild ... what is the average Time Between Overhauls?
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Small Engine Technician about your situation and then connect you two.
Submitted: 1 year ago.
Category: Small Engine
Expert:  Curtis B. replied 1 year ago.

Model number? What engine? Gas Kawasaki would be great at 130 psi!

Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 1 year ago.
Sorry about the delay...had to rescue gator from John Deere. I'm perplexed at what they told me. It is the 18 hp Kawasaki gas twin. 9.4:1 compression... they said it had only 130 psi with throttle open...how the heck is compression measured with a valve open? I've always done compression tests at TDC with valves closed..what does the throttle have to do with anything...my plane is very happy with 75 psi on a compression test...they want 170? Front cylinder is producing no power (stuck open valve?) Rear cylinder is running very rough...no idea why but since opening the throttle has little effect on rpm...is there a timing issue?
Expert:  Curtis B. replied 1 year ago.

140 is plenty of compression. Front cylinder, does it have spark? Are the valves working, pushrod not bent or broken> Vales set at .006 inch?