Honda lawnmower started smoking (GCV160)

dtestin

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It starts first pull and runs well. Compression is about 105. Did a leak down test and it has very low leakage (around 5% or less) based on Harbor Freight tester. It started smoking quite a bit this year and it is unknown age but likely 10-15+ years old. Plug is black with soot. With 105 compression and seemingly low leakage what may be causing the smoke?
 

ILENGINE

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Depends on the color of the smoke.. Blue smoke would indicate oil burning which could be overfilled. Black smoke would indicate rich running like either a leaking carb or even fuel in the oil. And both conditions can develop if the air filter has been wet with anything including water, oil, gas. So may want to try a new air filter and see what happens.
 

dtestin

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Thanks, smoke is blue. Oil level is full based on placing dip stick on oil inlet boss without screwing it in. I will try a new air filter.
 

slomo

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Pull the oil checker stick. Smell for fuel.

Could be carb needle is sticking open, choke stuck partially or fully closed or plugged up air filter. Valves ever checked?
 

slomo

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Was this recently tipped over?
 

dtestin

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Pull the oil checker stick. Smell for fuel.

Could be carb needle is sticking open, choke stuck partially or fully closed or plugged up air filter. Valves ever checked?
I don't smell any fuel in the oil. I have never checked the valves as it always ran great. It isn't used much anymore, just to do the edges where the zero turn can't get. I am going to try a new air filter.
 

slomo

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Does it start in 1-3 pulls? Do you have to pull your shoulder out trying to start it?

I would still pressure test the carb. Flip carb body over and pressure test the needle/seat at 7psi. Tell us what you get.
 

dtestin

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Does it start in 1-3 pulls? Do you have to pull your shoulder out trying to start it?

I would still pressure test the carb. Flip carb body over and pressure test the needle/seat at 7psi. Tell us what you get.
Almost always starts on 1 easy pull.
 

tadawson

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Honda engines used to be known for soft oil rings (not sure your model). Rebuilt my 1989 GX140 several years ago for excessive oil use/smoke . . . cylinder was still within "new" spec, new rings/seals and been perfect again for at least the last 6 and still going steong . . .
 
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