Export thread

Honda lawnmower started smoking (GCV160)

#1

D

dtestin

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?


#2

I

ILENGINE

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.


#3

D

dtestin

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.


#4

S

slomo

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?


#5

S

slomo

Was this recently tipped over?


#6

D

dtestin

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.


#7

D

dtestin

Was this recently tipped over?
It was not recently tipped over.


#8

S

slomo

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.


#9

D

dtestin

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.


#10

T

tadawson

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 . . .


#11

Craftsman Garage

Craftsman Garage

That would be bad rings, or a head gasket


#12

I

ILENGINE

That would be bad rings, or a head gasket
Just for a little info to store for later. The Honda GC and GCV series doesn't have head gaskets because the basically don't have a removable head. The head, cylinder and angle cut upper crankcase are molded as one piece You remove the matchig lower half of the crankcase to remove the crankshaft, so you can pull the piston and valves out from the bottom of the engine.


#13

Craftsman Garage

Craftsman Garage

What? 😦 I had no idea... I guess I'm just used to the design of the GXV140/60.


Top