i have an 18.5hp . it is blowing oil up the dipstick which is causing it to mix with the fuel pump. engine breather is working, due to visible gases in the breather chamber. could it be a stuck or broken valve?
#2
cpurvis
Probably not valves. They're at the opposite side of the piston than the crankcase. Might be piston rings, though. Just seeing 'gases' in the breather chamber is not an indication that it's working properly, though. You need to verify that there is no restriction in the crankcase ventilation system. It sounds like there may be, as the engine is using the dipstick tube to vent. Unless it has so much blow-by that the vent system can't handle it all.
Briggs & Stratton by any chance? If so, then most likely the head gasket is blown between the cylinder and valve area where the gasket is thinnest and farthest from the bolts to keep it torqued down. A cylinder leak down test can help identify the area of the leak.
If it is a B & S Intek then 99% chance it is a blown head gasket, very very common problem.
Just did one yesterday , blown at 110 hours, owner was real pissed, thought I was shafting him so I told him to Google Intek head gaskets, he rang back this morning an apologised.
Very important is to lap the head & block where the leak was otherwise it will become an every season job.
I have started fitting solid copper gaskets on the two larger singles and they seem to do the job a lot better.
Got Lanni ( coppergasketsus ) to cut some thicker ones ( 1/16" ) which are looking really promising.
Down here we can get aftermarket ones cut out of exhaust gasket sheet ( alloy top & bottom ) and they work really well with a bit of axel grease on the block side & Hylomar on the head side.
