Toro Zero Turn smoking

[Cboy553]

I work at a rental shop and just tore down a zero turn replaced rings and head gasket. Was burning oil badly like a quart an hour. Well now it smokes on start up for about a minute. Well I realize I had oil in the carb so I let it run half an hour. Anyway it still smokes on start up. Any ideas thank

 

[mechanic mark]

Check air filter for replacement, may be stopped up & not letting engine breathe. Check hose from air filter to reed valve at valve cover & reed valve itself if applicable. Did you drain oil from engine before disassembly on workbench? Check oil level on dipstick & see if it smells like gasoline. thanks, Mark

Post engine make & all information from engine, thanks,Mark

Parts | Toro

www.toro.com

 

[Cboy553]

Check air filter for replacement, may be stopped up & not letting engine breathe. Check hose from air filter to reed valve at valve cover & reed valve itself if applicable. Did you drain oil from engine before disassembly on workbench? Check oil level on dipstick & see if it smells like gasoline. thanks, Mark

Post engine make & all information from engine, thanks,Mark

Yeah I drained it. Cleaned the block really well. I honed it but my boss says it’s probably not honed very well
It’s a Briggs and Stratton 74350

 

[bertsmobile1]

Could be a bad hone but usually that would smoke all the time
Does it smoke on every start, hot or cold or only on a cold start ?
Did you replace the inlet valve oil seal ?

As a general rule
bad rings / worn bore smokes on acceleration
Bad vales smoke on the over run
So you grab the governor arm and work the governor between wide open and down the the idle stop
Don't over do the WFO bit

And don't rule out a head gasket leak unless you have done a leak down test .

If you installed the rings very wet it can take a few hours for the rings to bed in
If you installed them dry then they should have bedded in within a few minutes

 

[Cboy553]

Well it seems to smoke in both work or cold. And it only lasts about 30-40 seconds and clears up. If I shut off the motor and start right back up won’t smoke. If I wait about 10+ minutes before firing it up again then it’ll smoke

 

[bertsmobile1]

That is oil leaking under gravity down the valve stems most likely
If it clears up after a couple of seconds the it is nothing to be worried about

 

[Cboy553]

That is oil leaking under gravity down the valve stems most likely
If it clears up after a couple of seconds the it is nothing to be worried about

Problem is the boss ain’t happy and tells me the mower ain’t leavin the shop till it starts without smokin. Would a new head clear it up?

 

[bertsmobile1]

Well if he wants it to run like a new engine then it will need a rebore and new valve guides which means a new head
Or to put it another way
A new engine
Don't know how you can tell this to your boss without getting fired but it is an old machine
If the bore / rings was worn to the extent of a quart an hour then it needed a rebore and most mower engines do not have oversized pistons available anymore .

 

[Cboy553]

Well if he wants it to run like a new engine then it will need a rebore and new valve guides which means a new head
Or to put it another way
A new engine
Don't know how you can tell this to your boss without getting fired but it is an old machine
If the bore / rings was worn to the extent of a quart an hour then it needed a rebore and most mower engines do not have oversized pistons available anymore .

I think it needs a head replacement myself. I’m going to pitch it to him. The reason it was brought in to us was it was smoking badly and burning a quart an hour. So I think it’s doing fantastic compared to what it was. In my opinion I think the valves are the problem now.

 

[7394]

Did you replace the valve seals ?