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2006 19 hp. Kawasaki, it smokes on startup. I think it’s valve guides letting oil seep by. Can I replace valve guides at home or does a shop need to do the work?

Read through Service Manual above regarding your engine model.

I think if valve guides can be replaced it will stop the smoking upon start up. Fi can buy guides will I need to buy new valves also?

Nearly all Kawasaki engine smoke a little when first cranked up and this includes new engines. Unless the engine is using n usual amount of oil don't worry about it.

Smoking at start up can be a sign of overheating causing the oil the thin down too much
When you turn the engine off the thin oil ends up pooling in the combustion chamber and around the rings
Then when you start this oil burns off making the engine smoke for a few minutes
Many times the oil is not actually burning in the engine but in the muffler .

So check the engine for debris build up under the blower housing.
Idleing the engine down before shut off makes this worse .

bertsmobile1 said:

Smoking at start up can be a sign of overheating causing the oil the thin down too much
When you turn the engine off the thin oil ends up pooling in the combustion chamber and around the rings
Then when you start this oil burns off making the engine smoke for a few minutes
Many times the oil is not actually burning in the engine but in the muffler .

So check the engine for debris build up under the blower housing.
Idleing the engine down before shut off makes this worse .

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I did check the motor housing for debris while cleaning the flywheel and replacing the coils. Can you replace valve quite seals like on a older car?

StarTech said:

Nearly all Kawasaki engine smoke a little when first cranked up and this includes new engines. Unless the engine is using n usual amount of oil don't worry about it.

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The motor is an 2006, really doesn’t burn oil as far as smoking while mowing. It just on startups it does this. Figured it was valve guides or I could replace the valve guide seals and help with the skoke.

The seals can be replaced with the head on, if you are knowledgeable and resourceful. Air pressure can hold valves on their seats. Will need to compress the valve springs and remove to replace the seals

I would double check the cooling fins as someone was leading to above.

Ok I’ll double check them. It was all exposed four days ago when I replaced both coils. Thank you

Guides can not be replaced they are cast in as happens on most mower engines now days
Guide replacement rarely happens on any vehicle now days most auto shops will sleeve the valve
You are equating water cooled horizontal shaft engines with air cooled vertical shaft engines and they are cheese & chalk
To replace guides now days you need to machine out the guide and guides are very very hard then collapse the reminant into the hole
If you try to push it out you will destroy the head
Even then you will have to fit an oversized guide then real it out to give proper clearances for the valve stem
Valve stems are soft now days so they wear & guides don't .
Modern emission laws have air cooled engines running way too hot and I would bet your engine is running that tiny bit hotter
Down here mowers are not as strictly controlled as in the USA so it is legal for me to ream out main jets a tiny bit so the engine runs a little cooler and I have needed to do this on a lot of engines.
The 7000 series are really bad , on the B & S engines with 2 barrel carbs I toss the small jet & use 2 large ones
The other thing I do on engines that are cooking is to double the magneto coil gap,
This retards the spark a poofteenth which causes the engine to run a tad less hot.
You can not do a reliable plug chop on a mower engine because of the fuel solenoid but when I change the timing I check the spark plugs , if they are sooty then I have gone too far .
Remember mowers have fixed timing unless that are EFI models so the timing is never 100% accurate.
Several companies tried to bring invariable ignition timing and when it worked it was amazing but when these units failed it was a disaster but I really think the reason was cost as all of them used a triple wound coil.
I have a motorcycle with a flywheel magneto ( Yamaha SR 500 ) and the magneto + trigger unit+ flywheel need to be replaced as a matched set which is $ 1600 ( AUS ) and that is more than most Americans want to pay for a complete engine

The usual test for guides is to rev then decelerate the engine which on a governed engine will require you to work the governor arm.
So you go from wide ope throttle then shut it down completely
Smokes on accleleration = rings
Smokes on deceleration = valves
You have to be careful doing this because most engines will happily rev up to 5000+ rpm very quickly and at around that speed most pistons will depart from the end of the con rods

In nearly 12 years I have never needed to replace valve stem seals , most engines only have one on the inlet by the way , except in cases where the engine has well & truely cooked and needed new rings .
Some of my customers who had a lot of problems with smoking on start up were causing this to happen by idling the engines down before they shut off
Again a water cooled engine practice that is very bad for aircooled engines as the heat removal is exponential to the engine speed and heat generated is linear with engine speed
So in that minute or so when they thought they were "cooling" the engine they were in fact baking the engine and in particular cooking the heads

This is assuming your engine is good and the reason for replacing both coils was not some sort of catastrophic engine failure as you have not provided any back story

Ok I’ll double check them. It was all exposed four days ago when I replaced both coils

Thank you, you’re the only person that gave me the answer I was looking for plus you educated me on not idling it down and cooking the engine. Think I’m gonna do a compression check. What is good psi? Again thanks for your answer

Rls8836 said:

Ok I’ll double check them. It was all exposed four days ago when I replaced both coils

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Should not be a problem they are not UV sensitive

Rls8836 said:

Thank you, you’re the only person that gave me the answer I was looking for plus you educated me on not idling it down and cooking the engine. Think I’m gonna do a compression check. What is good psi? Again thanks for your answer

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Kawakasi say anything over 65 psi is fine
Mower engines are very sensitive to valve lash so strait compression tests are a bit meaningless which is why we all do leak down tests.
Just how much smoke is it blowing
A few puffs for a couple of minutes is normal

multigrade oils are made from a base oil with modifiers to slow down how fast they thin as the temperature rises
So a 10W 30 is a 10 weight oil when cold which is quite thin
Honda & kawakasi were the only companies that recommended multigrades till quite receintly
They were also know for a bit of smoke on start up as when cold the oil would drin out of the ring gaps & pool in the cylinder
On the first revolution that oil gets blown unburned into the muffler
From there as the engine heats up it will smoke for a few minutes till it burns off
Overheating will increase the amount of oil
Changing to a strait 30w can stop this happening