Briggs white smoke/oil coming out of muffler.

[Joe Hillmann]

I have a horizontal shaft Briggs. Model 100202, type 0145, QN 01, Serial 6311151. It is producing lots of white smoke, it produces clouds of smoke on start up until it is warm and whenever I adjust the throttle. Once it is warmed up and running at a constant speed it produces very little smoke but still some. Where the muffler blows onto the gastank the tank is dripping with oil.

This winter I removed the head and scraped all the carbon off and put it back together with the old head gasket I ran it for maybe an hour or two that way (before that the last time it was ran was in 1986, stored outside under a hood) Last night I took it apart and put in a new head gasket. Everything under the head was covered in oil. The exhaust valve was covered in carbon and the spark plug (only had 1 or two hours on it) was gunked up with carbon.

What would the people here suggest may be the problem? I am thinking it is leaking past the valves or I have broken rings (the bore of the cylinder looks to be in pretty good condition (no deep scratches)

[bgsengine]

You had a blown head gasket - or a crack or warped head allowing combustion pressure into the valve galley, which overpressurizes the crankcase, pushing oil out the breather and into the air intake. (and probably contaminated the air filter too.)

Or, simply a bad breather, or plugged breather drain hole.

[Joe Hillmann]

You had a blown head gasket - or a crack or warped head allowing combustion pressure into the valve galley, which overpressurizes the crankcase, pushing oil out the breather and into the air intake. (and probably contaminated the air filter too.)

Or, simply a bad breather, or plugged breather drain hole.

I am not disagreeing with you, but, can you explain how a blown head gasket or warped/cracked head would allow the pressure past the valves? I can't picture how that would work.

[bgsengine]

You had a blown head gasket - or a crack or warped head allowing combustion pressure into the valve galley, which overpressurizes the crankcase, pushing oil out the breather and into the air intake. (and probably contaminated the air filter too.)

Or, simply a bad breather, or plugged breather drain hole.

I am not disagreeing with you, but, can you explain how a blown head gasket or warped/cracked head would allow the pressure past the valves? I can't picture how that would work.

Combustion pressure blowing into the valve lifter galley where the pushrods are , nothing to do with rings or valves directly - and it only needs to be very slightly blown - you'd hardly notice it when it starts to happen as it would not affect compression or engine operation at all but that little bit of a leak past the gasket in between the cylinder and the valve lifter galley is what does the deed.

[Joe Hillmann]

I can see how that could happen on an engine with an over head cam but is that possible on an L-head engine?

[bgsengine]

Oh didn't notice you had an L-Head - In that case, you more likely had a breather issue - Breather installed upside down, the disk stuck or damaged or fell apart, drain hold plugged (not uncommon on un-maintained engines or those that got water in the oil - the tin breather rusts and the drain hole plugs up)

Or, if it is anything like the insect fogger I mow lawn with (runs great for a little while then a big puff of smoke every so often, usually under load or when tipping mower on wheels to change direction, or getting too rough and going over bumps, etc.) you got worn valve guides. - Engine runs great otherwise and starts fine, just has on-n-off smoking problem. That's why *I* am using it - not work fixing or selling.. and I was gonna make an example of it and change oil and put in Rotella-T just to demonstrate what happens using oil that isn't recommended! - Haven't done that yet as I have not had time to mess around with it.

a leak-down test would tell you if the rings are allowing too much blow-by. , other than that, it'd be valves, overfull of oil, or crankcase breathing issue.

[KE4AVB]

I have a horizontal shaft Briggs. Model 100202, type 0145, QN 01, Serial 6311151.

A blown gasket is one possible cause as BGS suggests which you have already replaced just sure you make torque it to 140 in lbs in three steps (torque all bolts to 1/3 , 2/3 and then finally full torque as to not warp the head).

Considering the age of this engine (a 1963) I would do a compression and leak-down test too. It maybe simply worn out rings and cylinder worn slightly oversize. Valves and guides are to be suspected too. Here normal crankcase pressure can push oil pass the valve guides when they are worn especially the exhaust one cause the engine to smoke heavily at start up. This is not as common as in vertical engines as the valve train is vertical in a horizontal instead horizontal as is in vertical engine.

Side Note:
I just had one horizontal 130000 series in the shop that the same symptoms as you describe. Heavy oil burner. It was simply worn out. I did a leak down test and it was leaking pressure everywhere but it was still running. I didn't even bother to do a compression test. I check the cylinder; was .008 over. Look at the top ring end gap, didn't pull the piston to check the others but top ring had a gap of .060 (reject gap is .030). Exhaust valve was burnt and leaking. The intake valve so worn that it didn't even fully close. Valve guides were worn out too. On top of all that the head gasket was blown and the spark plug badly fouled. I put it all back together and try starting it. Surprisingly it started up. I couldn't see anything in my shop after a minute or so even with the doors open.

I finished putting together an estimate and the customer said he wanted me to rebuild it but he had to save up the money first. Since it is a heavy flywheel version with plenty after market parts it is affordable for this customer to rebuild it.

[Joe Hillmann]

Once it warms up again I will check the crankcase breather. I just took a look at it and from the outside is is so covered in dirt and oil that I had to scrape it away to even find it.

The engine may just be warn out but I kind of doubt it. I no longer have the tools to measure and test the compression and bore size and clearances (my small engine tool box was stolen this winter) If the breather isn't the problem I will probably just use it till it dies.

[bobodu]

Sometimes that's kinda fun.....might even take years.