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Brettw

Briggs oil blow by

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Brettw

Hi all, Recently I sold a Vanguard twin as I had a 16 horse original single to replace it in a 7116 I acquired.  Bought the engine without having seen it run.  It was complete and out of a 7116.  Clean, and a newer version without points or the even the cover.  It was not converted.  Has good compression.  I did clean out a mouse house, however, it was not packed full.  Put a bit of fuel in the throat body to begin with, just to see if it would even pop.  Fired right off.  Next step, bolt it down, clean up the carburetor, add fuel and see what we get.  Starter up, ran very well.  Increased the rpm's, all is good.  Then, a LOT of smoke.  Shut it down, and began the check.  Oil, and a lot of it, in the carb body, coming from the breather.  Time to pull the head and see what I can.  Clean, cylinder good, piston good and clean enough to easily read STD standard on top.  Not much carbon build up at all.  That's as far as I got as I ran out of time.  Not having a lot of Briggs knowledge, what's a good bet to start the hunt for the issue?  Bad breather?  Valve guide/seals?  Could be rings?  Stuck Ring?  Oil level appears correct, but maybe the wrong dipstick?  Any suggestions from the Briggs boys would be much appreciated.  Trying to eliminate the issue by looking at the easy stuff first. 

Edited by Brettw

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SimpleOrange

Oil in carb definitely a faulty PCV valve which seems to be a prominent Briggs ailment, if it were me I would remove the innards then modify the Briggs breather case to accept a PVC valve from an older style GM V8

The PCV valve shown below is meant to be installed inline, I think you would want the one that pushes into a rubber grommet

 

 

 

pcv.png

Edited by SimpleOrange
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MARK (LI)

Hey Brett....I can't help you at all, but this topic is something a lot of us can learn something from...any possibility you could post some pictures......thank you ....  Mark

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BLT

I'll put my money on the breather. They do fail and it floods the carb air inlet, I have had one one on a 20 HP command and one or two do on the CI's where they have a closed closed crankcase.

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Brettw

I am going to check that, Bob.  Probably could use a good inspection and cleaning anyway.  However, the problem stopped when I tried it again, maybe a stuck ring or breather part?  Seems to be OK now after being run for a bit and sitting.

 

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MrSteele

Remove the valve. Shake it, if there is no noise, it is stopped up. It can be cleaned. Let it soak in your favorite solvent for a while, then blow out with compressed air. Repeat, until a slight shake makes it rattle. Spray carb cleaner will speed up production. Keep the cleaner off your body, wear gloves. Blow out with air until you have an easy rattle in the valve, then replace it on the engine. That trick used to yield me a lot of discarded engines.

While you are in the cleaning mood, I assume you still have a foam air cleaner? If it is stopped up, it will also give basically the same result. The engine needs air from somewhere, will suck it out of the crankcase through a stopped up PCV valve. If it does not crumble when removed, wash it and try again, or replace. Do the easy things first before going deeper. Let us know

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