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First please bear with me, I'm very new to the engine repair world. It's becoming a fun hobby but I'm still quite green.

I have a Simplicity 4211 with a Briggs and Straton 1690459. It ran perfectly last time out. This time it had a lot of white smoke, the engine would race then cut out. It looks like it's leaking oil. A lot of sites say it's the Head Gasket. I've looked a lot of engine diagrams and I can not find how to get to the head gasket on this engine. (Does it have one?) I drained the oil and noticed it was not very thick. I'm guessing it somehow has been mixed with gas.

I took apart the carb and cleaned it late last summer and it was working fine for the last 8-10 times I've used it.

Any thoughts or direction would be appreciated.

Thank you.

It's probably not the carburetor. If the fuel/air mixture gets too lean, it quits running. If it gets too rich, the engine emits black smoke (not white) and eventually quits running.

Your engine does indeed have a head gasket. If you're having trouble finding the head bolts, do you think you should be attempting this repair by yourself?

Lets start with a correct model number for the briggs engine. If on OHV engine should be located on the valve cover, or on the blower housing if flat head. Above the spark plug, or next to the flywheel. Will actually say Model Type Code next to the numbers

cpurvis said:

It's probably not the carburetor. If the fuel/air mixture gets too lean, it quits running. If it gets too rich, the engine emits black smoke (not white) and eventually quits running.

Your engine does indeed have a head gasket. If you're having trouble finding the head bolts, do you think you should be attempting this repair by yourself?

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Thanks for responding. I do know enough to understand where the head bolts are located, but you are correct in assuming that I am going into uncharted waters. I'm interested to learn however and I've decided to undertake the the challenge of seeing how long I can keep this old mower going. Worst case scenario is I screw it up and need to invest in a new mower which I probably should have done a few years ago. And direction someone can provide is helpful.

ILENGINE said:

Lets start with a correct model number for the briggs engine. If on OHV engine should be located on the valve cover, or on the blower housing if flat head. Above the spark plug, or next to the flywheel. Will actually say Model Type Code next to the numbers

Click to expand...

Thank you for responding. Yes, the correct model # would be helpful. I wrote the first post from work and went from what I knew off the top of my head. The model # is 281707 0162 01 88082431 It's located next to the spark plug.

It looks like there was oil flying around in there. I had to clean the area to see the number and lower it looks like more oil splattering. Now that I have the correct model # I have now found the engine diagram with part #'s I was looking for that answers my Head Gasket question.

Do you have a guess as to what the issue might be?

Here is a video of the engine racing then stalling....

Shouldn't have a problem with mosquitoes.

My guess, and that's all it is, would be that it has a broken piston ring.

But how could it have been "fine" the last time you used it and have all that oil on the muffler (not "in" the muffler)?

It is possible that the head gasket is blown in the area of the exhaust it could also be possible that the engine being almost 30 years old could be reaching its end of life. Oil seeping past the rings leaks out on the muffler through the blown head gasket, and when started proceeds to burn the oil out of the cylinder, and what has dripped onto the muffler.

Double check the oil level and make sure it doesn't smell like gas, because thin oil could make the problem appear worse than it is.

cpurvis said:

Shouldn't have a problem with mosquitoes.

My guess, and that's all it is, would be that it has a broken piston ring.

But how could it have been "fine" the last time you used it and have all that oil on the muffler (not "in" the muffler)?

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I'm not sure why the sudden change in behavior. Last time I had it running was two weeks ago and it has no smoke or other issues. The only thing I did between now and then was fill up the gas tank. Don't know if that has anything to do with the oil having a very liquid viscocity, it hasn't in the past. I'll take it apart this weekend and see what I can find.

If something else crosses your mind, I'm very willing to listen and learn.

Thanks again for your help.

ILENGINE said:

It is possible that the head gasket is blown in the area of the exhaust it could also be possible that the engine being almost 30 years old could be reaching its end of life. Oil seeping past the rings leaks out on the muffler through the blown head gasket, and when started proceeds to burn the oil out of the cylinder, and what has dripped onto the muffler.

Double check the oil level and make sure it doesn't smell like gas, because thin oil could make the problem appear worse than it is.

Click to expand...

The oil was very thin. What could have caused it to get that way? It was not tipped on it's side or anything of that nature.

Thanks for your help.

The very thin oil could mean it is mixed with gas from a leaking carb, which could also explain the smoke at start up.

Sounds like your carb needle and seat agree leaking.
I just did a Briggs L head 12hp today. Parts 10.98 total.
Two main styles but basically most commonly a brass pressed in seat in carb and a rubber tipped needle valve that the float pushes up to shut off fuel.
Comon signs are empty or lower fuel than when you parked it, fuel in oil, fuel puddling in throat of carb, needing no choke to start, and smoke on start up after sitting.
Replace needle and seat then change oil and filter but I don't think yours has a filter.