Fs481V running perfect but smoking a lot

L

loadedmango

Forum Newbie
Question for yall...I just got a scag 32" mower with the Kawasaki FS481V motor. When I got it it was on one cylinder because the valves were out of spec and one of the valve adjustment collars was split.
After addressing all that she starts 1st pull no choke cold and hot every time and runs without a hitch with full power and mows great. However as soon as it is warm there is a lot of grayish smoke. The oil is fresh and filled just a smidge below the full mark with the cap not screwed down.
I did a leal down test on both cylinders and got <5% leak with hissing from the oil fill and no noise from intake or exhaust.
I just changed the fuel pump thinking the Diaphragm must have a hole but no change.
My next thought is head gasket or piston rings but I am thrown off because of the leak down test...any thoughts?
 

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Typically a puff on startup is dead valve seals. Smoking all the time is rings. Course could be a combo of other things too. Most likely from lack of maintenance. Dirt/grit getting by the air filter killing the rings. Every mower engine does it. Every used mower I get, pull the carb off and look in the intake tract. Bottom will be full of tiny grit that gets passed the air filter. I use GE 100% silicone and glue mine on to the air filter housing. SAE 30w oiled foam pre air filters and so on. Got to get drastic stopping dirt from getting inside.

Are the plugs black too?

Could be from someone adding too much oil and running it.
 
slomo said:
Typically a puff on startup is dead valve seals. Smoking all the time is rings. Course could be a combo of other things too. Most likely from lack of maintenance. Dirt/grit getting by the air filter killing the rings. Every mower engine does it. Every used mower I get, pull the carb off and look in the intake tract. Bottom will be full of tiny grit that gets passed the air filter. I use GE 100% silicone and glue mine on to the air filter housing. SAE 30w oiled foam pre air filters and so on. Got to get drastic stopping dirt from getting inside.

Are the plugs black too?

Could be from someone adding too much oil and running it.
Click to expand...
I just put new plugs in and they are a little black because there is definitely oil burning. The only reason I haven't done the rings yet is because the leak down test was so good...
I had a guy tell me to check out the crankcase ventilation system to see if it is clogged or malfunctioning which I'm gonna do tonight. Do you have any experience with that on this kind of motor?
 
Hello L.,

Intake valve seals could be tired and worn.

Verify the crankcase breather is clear and there is no air cleaner to carburetor gasket restrictions.

The only other concern I can think of for the moment is if the carburetor is weeping fuel past the needle and the engine oil is getting washed down and thinned out
 
Unless you do a modified leak down test you can be missing lower cylinder problems as standard leak down only checks the upper cylinder. This modified test can only done on OHV and not L heads.

Now the modified test does require disabling the valve train.
 
So I was able to confirm tonight that it is a ventilation system malfunction! I disconnected the breather hose from the intake and mowed for 30 minutes with no smoke!! I'm gonna order a new gasket
Thanks for all the help!!
 
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