Briggs and stratton help


Old 04-16-06, 07:48 PM
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Briggs and stratton help

I have a sabre lawn mower with a 15 hp Briggs and stratton engine in it( model 28N707). When I got it, the engine had an oil leak between the two case halves and a blown head gasket. So i decided to rebuild the engine and followed a manual to get all the torque specs. and tolerances needed. So after I was done rebuilding the engine, it ran fine. I used it 4 times now and all of a sudden today, I am getting blueish/white smoke emiting from the exhast and the air filter element is covered soaked in oil. Also, the whole intake/carburator side of the engine and the whole front of the lawn mower and covered in oil. I'm stumped as to why this is happening. Any help would be great.
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Old 04-16-06, 08:15 PM
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Head gasket...... was the head and cylinder mating surface checked to see if it was good and flat?
Old 04-16-06, 08:24 PM
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Valve cover-There's a round popit valve in the valve (breather) cover this valve gets rid of any air in the crank case so as to keep a vaccuum in it.And when the head gasket blue, it sucked air into the engine,spung this valve allowing oil out as well. part # is 696126 for the beather cover and 27803 for the gasket.
Old 04-17-06, 12:15 AM
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It could be the head gasket blown again, or the breather/pcv valve, or it could also be that there is gas in the oil due to a leaking needle valve in the carburetor.
Old 04-17-06, 04:59 AM
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Since it is rare for the breather to fail and assuming you did, in fact, torque the cylinder head properly, smell your oil for any sign of gasoline. This is my guess as to the problem you Cheese mentioned, fuel in the oil, requiring a carburetor rebuild. When gas enters the crankcase, the breather cannot handle the added pressure and must be evacuated somehow. By way of the breather hose (which connects to the air filter) and/or blowing past the rings and coming out the exhaust in a blue smoke form.
Old 09-13-07, 09:10 PM
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Blowing Blue Smoke

I want to thank you for posting the information regarding the gas-smelling oil. Here is my story with some questions at the end.<BR>
I have an 18 HP B&S engine on my MTD riding lawn mower that I purchased used and not running. After new starter and rebuilding fuel pump, and thoroughly cleaning out the carburetor, I was able to get it started only to have it blow blue smoke. During troubleshooting, which included making sure there was not too much oil, I smelled the oil and it smells like gas, old gas. I believe the gas in the oil was a pre existing condition to my rebuild/cleaning. I say this because I only ran the motor for 15 seconds and the blue smoke started almost immediately. Tomorrow, 9/14/07 i plan to change the oil and try her again.

Here are my questions - If I corrected the problem with the carb, and if there is gas in the oil, would I still get blue smoke? (Would blue smoke only appear if there was still a problem with the carb?)

I still haven't ruled out possible problems with the breather because when I got the mower there was lots of oily residue all around the base of the crankcase which spilled down to the frame. I haven't ruled out that it is the seal at the PTO, but the PTO is not wet.

ONE UTTER THING - where in the heck is my breather ?
Old 09-14-07, 01:00 AM
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Yes, the gas in the oil will continue to make the smoke until it is drained and refilled with the correct oil SAE30. The gassy oil is also probably the cause of all the leakage you see. Once it is at the proper level with the right oil, it probably won't leak, or at least not as much.
Old 09-28-07, 06:46 PM
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Follow Up by Rain Man AV as promised

I changed the oil and I figured out where the breather is located. I removed the breather, shot the breather tube side with a bunch of engine degreaser, shook it a bit and then washed it out thoroughly with water. The part of the breather which mounts inside the engine, I blew on that sucker to help remove any remaining water. I then sucked on it to make sure the breather works properly, and it does. I then laid the unit out in the sun to dry roast to help evaporate any remaining water. After reinstalling and reconnecting the breather tube, air cleaner and cover, I started it and it puffed a little blue smoke at start up which then stopped once I set the choke. It now runs like a top. After sitting for a few days I started it again, blue smoke on start up, and then none after adjusting choke. No more gas in oil.


Thanks to all that provided information that helped me determine what I needed to do. You guys rock.

also, I haven't run it long enough to determine if the seal at the PTO is bad, but I do plan to replace the grommet at the base of the oil fill / oil dip stick tube.
Old 09-29-07, 01:13 AM
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Glad you got it and thanks for the update! You know where to find us!
Old 03-06-08, 11:16 AM
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18 hp BS..was wondering if anyone could tell me why one cylinder doesn't seem to be firing, or firing correctly. I checked coils and plugs, both seem to be emitting good spark. That one cyl doesn't get as hot, nor does the compression seem to be as good when compared to the other cyl.
Any insight would be appreciated

Old 03-06-08, 12:34 PM
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Could you post the model, type, and code of engine and tell us what the compression values were for each cylinder.
Old 03-07-08, 12:35 AM
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Sounds like the engine threw a rod on one side. If so, the other is probably not far behind. Take out the plug, insert a pencil until it hits the top of the piston, then turn the engine slowly. Does the piston move? If not, it broke a rod.
Old 06-12-08, 06:16 PM
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where is the breather???

I have a vanguard 18 vertical and don't see any breather on it/
Old 06-13-08, 12:04 AM
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Follow the rubber hose from the air filter housing to the breather.
Old 08-13-08, 09:31 AM
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Originally Posted by Nick Grey View Post
Hello there, you lot seem to talk sense, can you help with this:
I have an Entec Woodchipper with a Briggs and Stratton 18hp Vanguard 350447 V twin engine.
It always started fine when cold but was horrible to get going when hot.
Last time out it wouldn't start from cold, eventually it coughed into life on one cylinder and smoke came billowing out of the exhaust followed by oil.
Does it sound like a blown head gasket? I took the heads off and one cylinder had oil in it.
The engine is coupled to a heavy rotor on the chipper via 3 v belts and is hard work to pull start. It says its low compression and must be run at idle before turning off but last time out it jammed some wood in and stalled when it was hot. As it is so hard to start when hot I put it away and when I tried it again today the problems showed. Thanks for any help. Nick

May I suggest you start a new thread? This one has already changed subjects more than once and gets confusing.

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