Briggs Stratton smoking.

[norsa]

Having got the mower bodywork done (this forum: mower project/automotive projects) The engine now needs sorting. Its burning a sump full of oil in about 1hr. Know little about briggs engines but lots about car engines so im assuming as i cant find a plate to adjust the valve clearances, it is non adjustable so looking to head gasket/rings ?????????? Anyone. Circa 1986 by the way.
Nick

 

[Robotstar5]

Was it burning as much before the overhaul?, it may be just rings stuck

 

[norsa]

no she smoked before the rebuild. not clouds but enough that id like to get it sorted before she seizes.

 

[Engineer1964]

Its burning a sump full of oil in about 1hr.

Now thats pretty serious, Did you do the rebuild yourself or someone else??

 

[the snooper]

they usually have a crank case breather thats connected to the side of the carb, check oil is not entering there, also how did you store the engine when you removed it, they dont like being stored at a angle and it may have filled the exhaust with oil, hence it smoking worse after the rebuild

 

[norsa]

I did the rebuild.
Crank breather is a wise shout but if oil is getting in the carb via the breather, what would be the cause?
Its not smoking more since the rebuild but as the rebuild got more comprehensive than remedial, i would like to sort the oil issue now.

 

[the snooper]

it should have a little oil separator follow the breather pipe and if memory serves me it should go to a little plate with 2 bolts remove it and check for blockages

 

[norsa]

thanks. ill give it a try.
Nick

 

[Pete.]

If the engine has been tipped on it's side - carb upwards - the breather will be full of oil and it'll smoke out the whole neighbourhood whilst dripping oil on your path. I know coz my son in law turned mine on it's side when it wouldn't start to un-jam the pull-cord mechanism.

Remove the exhaust, and the breather is visible underneath. Take that off and make sure the reeds are seated properly, then just flush it out with some petrol to get all the oil out. Whilst you are at it, remove the little cover on the side of the engine and make sure you have about 10 thou clearance between the pushrods and the valves. They close up and make the engine run poorly but there's no adjusters. If you haven't got the gap, grind a chisel-point on a small flat file and work that in there to file a gap between the valve head and pushrod, they aren't hardened so it only takes a few minutes.

 

[Flathead_Dave]

If it's a single cylinder sidevalve,check to see if the model number is listed here.

http://www.amazon.co.uk/Briggs-Stratton-Genuine-270962-Manual/dp/product-description/B00004TKNL

If it is,it looks like you can download that manual here.

http://www.4shared.com/office/zwxRLo0D/270962_single_cylinder_l-head_.html

It's for single cylinder sidevalves after 1981.

 

[Lawnmowerboy]

Most of the time it is valve guides on brigg'ses causing them to smoke. You have to set the valve clearances by grinding the valve stem down.

 

[norsa]

thanks all, a few things to look at there. ill set about pulling it apart. would it be worth a head gasket and set of rings and go right through it or would you say if its not a breather issue its going to be guides and not worth spending engineering money to replace. The option is to replace the engine but dont know where to start looking for one.
Nick

 

[Windy Miller]

thanks all, a few things to look at there. ill set about pulling it apart. would it be worth a head gasket and set of rings and go right through it or would you say if its not a breather issue its going to be guides and not worth spending engineering money to replace. The option is to replace the engine but dont know where to start looking for one.
Nick

If it turns out that the engine's shot, I have a Techumseh engine that may do the job for you. It was a petrol jet wash in a previous life, but the pump is missing.

 

[Tengtooltom]

you just compress the valve springs remove spring cap and pull out the valves. You can file or grind down the stems to get about 10thou clearance after giving a lap in. I have reused the old headgasket on many engines. These are not vert high tec motors.
New engines are not very expensive to buy complete.

 

[norsa]

Appreciate that but I was talking guides not the valves which if they are on a car, need pressing out and back in mate.

 

[Tengtooltom]

B & S valves and seatings can be done in 20 to 25 minutes. 3/8, 7/16 and 1/2AF spanners and a long nose pliers. Do the valve faces and lap in. Make sure that the ports are cleaned and free of carbon buildup. If the valves do not seat properly it will create a vacuum in the crankcase, syphon the oil and burn/blow it out the exhaust. Try it out!!

 

[Pete.]

You need not remove the valves to do the clearances, it's a trivial job to just file them with a thin fine file.

 

[Lawnmowerboy]

You can't change briggs valve guides just for the record.

 

[norsa]

best i get her on the bench again then . Thanks all.
Nick