Pulled the valve cover off B&S and it was flooded!

[Jssussex]

I have a saber with a B&S 28n707-1635-e1 single cylinder engine that was blowing smoke. When I pulled the valve cover off it was flooded with gas. Is this a sign of carb problem or a head gasket problem. I thought the smoke was a head gasket but now I'm not so sure.?....

Never mind, I just spoke to a local B&S service center and he said the ethanol had dissolved the tip of the needle valve and it was letting gas leak into the engine when it sets idle and eventually floods the system and floods the crankcase. The simple solution is to add a shutoff and turn off the gas when the mower is off. I have to drain the oil including manually stroking the engine. He said be prepared because when I open the plug the oils and gas is going to pour out. Then let it dry out for a couple of hours and then add the new oil. When I restart it it will below smoke until the muffler burns the remaining fuel out of the exhaust system.

I'll post an update if this isn't the final solution.

Jim

Wednesday April 25th -

Well this worked perfectly. I've ran it 4 times now and used the shut off. It's running great and it cuts great. Im considering purchasing an electic shut off so I don't forget to turn off the gas when I park the tractor.

 

[jmanatee2]

Just to let you know that exact thing has happened to me. I used the same repair,... works great (except I always forget to turn it on the next use)

 

[MHarryE]

Interesting they blame it on ethanol in the gasoline because something similar happened to my 1997 snowmobile in which I only used off-highway / collector car gasoline, the only gas in MN that doesn't have ethanol and cannot be used in new cars ( by law, not that it won't work). Small engine shop I talked to said it is just a matter of time - things wear. Mine was factory equipped with a fuel shut-off. I learned it was there for a purpose but they also have plugs at the bottom of each cylinder so you can drain the gas from the crankcase when you have a memory lapse. Trails ring them for a couple hundred miles without shutting off the fuel and you are sunk unless you keep putting in new seats and valves.

 

[Jssussex]

I'm not saying it could be something else that could wear out the needle valve. These guys are small engine repair and it's their theory of why. The important thing is that they were able to give me a diagnosis that seems to be correct.