B&S smoking on startup

[jerrycmorrow]

Got this 10+ year old self propelled mower with B&S engine. Starting this spring it smokes heavily upon starting. Smoke gradually disappears in about 5-10 minutes. Might still be a little smoke then but hard to say given the “grass” I cut; mostly dirt. I’m sure I’ve read about this before and suspect it might be valve seals but not sure. Little help would be very appreciated. TIA. Jerry

 

[Scrubcadet10]

Model and type numbers, please.
if it's a flathead engine, they will be stamped on the metal above the spark plug or on the flap above the muffler.

 

[jerrycmorrow]

11P902-0693-B1

 

[Scrubcadet10]

It either going to be valve seals, or a blown head gasket.
Oil level is good as well?
Start the mower and let it warm up. shut it off, and remove the oil dipstick, look for whisps of smoke coming out of the dipstick tube, that is one tell tale sign of a blown headgasket.

 

[Scrubcadet10]

parts lists if you need it

PartsTree - Home of OEM Parts for Outdoor Power Equipment

Parts lookup and repair parts diagrams for outdoor equipment like Toro mowers, Cub Cadet tractors, Husqvarna chainsaws, Echo trimmers, Briggs engines, etc.

www.partstree.com

 

[7394]

What weight oil have ya been using ?

 

[jerrycmorrow]

It either going to be valve seals, or a blown head gasket.
Oil level is good as well?
Start the mower and let it warm up. shut it off, and remove the oil dipstick, look for whisps of smoke coming out of the dipstick tube, that is one tell tale sign of a blown headgasket.

Oil level fairly good. Have to top it off every 3-4 uses of about 2 hours each

 

[jerrycmorrow]

What weight oil have ya been using ?

30 wt

 

[7394]

30 wt

My much older B&S flathead used to use oil too, when I service it, it takes 20 oz of oil (dry), I put in 18 oz of 30 wt, & add 1 oz of STP.
It seems much happier.
And STP is loaded with ZDDP.

 

[Joed756]

Is it the blue smoke of burning oil or is it white smoke indicating fuel? If it's white, install and use a fuel shut-off valve