1988RedT2 MegaDork
7/3/20 3:39 p.m.

So, my son has been making some spending money mowing the neighbor's lawn.  With my tractor.  He brings it back this last time and says it's been running hot.  I'm like "How do you know it's running hot?"  His reply:  "Because it's smoking."

I look it over.  The thing started the job full of oil.  It was below the "add" mark an hour later.  Hard to tell where it's leaking.  The whole thing is covered with a layer of oily grass clippings.

I need to clean it up and run it and see if I can find the source.  Anybody know where these things tend to leak most often?  Tractor is a Husqvarna YTH5424.  Engine is a B & S Intek 24 HP V-twin.  It's got maybe 200 hours on it. 

jgrewe Reader
7/3/20 4:07 p.m.

Oil filter or valve covers and pray it isn't the main crank seal on the bottom.  Or they can barf out the dip stick seal.  I've had a bunch of the Vanguard series  and that is where they end up leaking.

1988RedT2 MegaDork
7/3/20 4:18 p.m.

I wiped it off a bit and it definitely looks like the valve covers are leaking at least some of it.  The shaft seal area seems dry.  Oh, and it's got a little over 300 hours on it.

I think I'll put valve cover gaskets on it and go from there.

Purple Frog (Forum Supporter)
Purple Frog (Forum Supporter) Reader
7/3/20 9:40 p.m.

If a ring fails it will pump oil out of any seam it can find.   sad

Check the breather tube to make sure it is not displaced.

1988RedT2 MegaDork
7/3/20 10:04 p.m.
Purple Frog (Forum Supporter) said:

If a ring fails it will pump oil out of any seam it can find.   sad

Check the breather tube to make sure it is not displaced.

Would that not also manifest itself as poor running?  I'm going to pull the plugs tomorrow and see if anything looks amiss.

hobiercr (FS)
hobiercr (FS) SuperDork
7/4/20 10:12 a.m.

While you have the valve covers off, check the head bolts and adjust the valves. I let mine go a little too long, bent a pushrod and ended up doing a full teardown.

914Driver MegaDork
7/4/20 11:55 a.m.

I bought a snow blower from a neighbor once, he said it was burning oil.  I removed it from the frame and noticed a bolt jammed into the crank case vent tube.  With no PCV, it sucks oil into the intake. 

I found a B&S parts site when looking gaskets for a 4hp horizontal engine.  Curious how this ends.

Patrick (Forum Supporter)
Patrick (Forum Supporter) MegaDork
7/4/20 12:53 p.m.

Going to piggy back.  Have a 2011ish MTD 42" mower with a b&s engine.  Last time i cut grass it bogged and sent a giant oil cloud out the muffler 4 times, like giant enough that I couldn't see anything.  Then it ran fine and has been fine since while moving the little yard cart trailer around.  What should i look for?  I don't speak small engine very well

11GTCS Reader
7/5/20 2:14 p.m.

In reply to Patrick (Forum Supporter) :

If it’s new enough to have a solenoid valve on the bottom of the carb it’s possible it’s leaking by when off and letting gas into the crankcase.  Many of the Vanguard engines with this feature that get condemned because they’re “seized” actually are hydrolocked with fuel.   Mine failed the other way, the solenoid coil will get weak over time when it’s hot and shut the fuel off stalling the engine.    Check your oil level the next few times you use it, if it’s making oil the solenoid is a fairly inexpensive and quick fix.   Not likely to cause the smoke show you’ve had but the valve clearances need to adjusted periodically on the OHV Briggs engines, mine were about .003 over tolerance before adjusting them and would result in a no start when hot.  

1988RedT2 MegaDork
7/13/20 1:55 p.m.


Replaced the valve cover gaskets a few nights ago.  Checked valve clearances while I was in there.  Did not bother to adjust as they were at the upper limit of the spec. range (.006) or slightly higher.  I feel like the oil is leaking a bit less, but still very much leaking. 

I think it's dripping onto the center of the exhaust cover on the front of the engine.  Hard to tell exactly where it's coming from.

1988RedT2 MegaDork
7/13/20 6:05 p.m.

Well, I'm going to throw another part at it.  It's gotta be the main shaft seal.  What's deceptive, is that the shaft and pulley don't seem all that wet with oil.  What I assume is happening is that it leaks only when it's running and it throws a relatively fine spray off of the rotating pulley.  The clue is that there is oil up in the front part of the engine hood/cover that could not get there any other way.  It's definitely getting flung up there.

I'll let y'all know how that goes.  smiley

Our Preferred Partners