I was just given an old Jacobsen Snowthrower. It seems to be a good old workhorse but when it gets under a load it seems to blow oil out of the overflow tube. I don't have a manual for it. But it is an old Tecumseh engine...probably around an 8hp. Any ideas as to what might cause this?
Thanks in advance, tom
Assuming you haven't filled it with beyond it's capacity, then:
It sounds like a lot of "blowby" from the combustion chamber around the piston and into the crankase. Could be just stuck piston rings, but more likely it's wear on the cylinder bore.
It's not really economical to pay someone else to repair a worn out single cylinder engine these days. You can buy a whole new engine for under $300 if you shop around.
Jeff
The other fellow had some good ideas. Namely to pull the dipstick and see if the engine oil is over full. Total system capacity is some where around 16 to 20 ounces. Might want to drain it and change the oil anyway.
Let me add one more option.
It's been awhile since I worked on a Tec 8 HP. But.... on the same side of the engine as the carbeurator should be a small access plate, about an inch high and three inches left to right. It is held on with two bolts which are tiny (1/4 or 5/16 nut driver). There may possibly be a small tube which goes from this plate, to the air intake.
This "plate" is a check valve. It is designed to allow air out of the crankcase, but not allow it back in. So when the piston is going up and down, the crankcase can operate at a very slight vacuum, but not under pressure. Sometimes these check valves get dirty,a dn they don't work right.
Take the valve off, and spray it out with carb cleaner, or maybe soak it in gasline and very gently brush the crud off of it. Put it back (careful, there is usually a gasket under the plate,a dn the gaskets are usually dried and brittle). See if that helps.
that's a briggs. techumseh had a seperate breather . if the breathe got plugged anyway it would blow a crankcase gasket or seal. what the OP has is a worn out motor. Chip
Whoops! Like I say, it's been a while. Thanks for catching my misteak.
Sounds like that thing has a blowby problem. Tecumseh engines are nothing to be amazed at... in all truth they are one of the cheapest POS engines made. Find an old Briggs to put on it, or trash it.
Tony Kimmell
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