31F707 0112 E1

PTmowerMech · Sep 18, 2019

It spits out a puff of smoke on start up. Runs fine with almost no smoking when it's running. But when I kill it, another bigger puff of smoke comes out. I know it's got a bad head gasket. I can see quite a bit coming out the fill tube after running it for a few minutes.

My question is, is the head gasket causing the puff of smokes? Or could it be something else. I'm getting good compression. 120lb or so.
The ole plug, before i pulled the head was coated thick with black burnt oil.

Just waiting on the new head gasket. But wanted to check to see if the smoke puffs could be something more severe (like bad rings) before I went to far with this engine.

Fish · Sep 18, 2019

Nah, likely just the head gasket.

tom3 · Sep 18, 2019

Somewhere on that engine should be a crankcase breather tube to the air cleaner. Take it off and see if there's blowby. If there's some serious smoke the rings are probably shot, or the cylinder is messed up.

PTmowerMech · Sep 19, 2019

tom3 said:
Somewhere on that engine should be a crankcase breather tube to the air cleaner. Take it off and see if there's blowby. If there's some serious smoke the rings are probably shot, or the cylinder is messed up.

Yes, I forgot to mention a lot of smoke coming from there.

How do you check the ring gap?

Fish · Sep 19, 2019

That is from the blown head gasket. They blow out normally in the thin strip of gasket that sends compression down the pushrod gallery to the crankcase.

PTmowerMech · Sep 19, 2019

Fish said:
That is from the blown head gasket. They blow out normally in the thin strip of gasket that sends compression down the pushrod gallery to the crankcase.

View attachment 45660

Yup, that's about what mine looked like. Had two smaller gouges in it, right there in the same spot.

That's how the pressure in the engine gets built up and comes out of the PCV.

You folks are geniuses.

cpurvis · Sep 19, 2019

PTmowerMech said:
How do you check the ring gap?

Remove the rings from the piston(s). Then invert the piston and use it to push each ring down in the cylinder bore. Check the gap with a feeler gage. Do this at top and bottom of the ring's travel to check the cylinder for taper.

PTmowerMech · Sep 19, 2019

cpurvis said:
Remove the rings from the piston(s). Then invert the piston and use it to push each ring down in the cylinder bore. Check the gap with a feeler gage. Do this at top and bottom of the ring's travel to check the cylinder for taper.

Ah, rats. Was hoping a there was a way to see the rings without having to pull them. At least the top one.

Fish · Sep 19, 2019

PTmowerMech said:
Ah, rats. Was hoping a there was a way to see the rings without having to pull them. At least the top one.

It's likely just the head gasket.......

31F707 0112 E1

More options

PTmowerMech

Lawn Addict

Fish

Lawn Pro

tom3

Lawn Addict

PTmowerMech

Lawn Addict

Fish

Lawn Pro

PTmowerMech

Lawn Addict

cpurvis

Lawn Addict

PTmowerMech

Lawn Addict

Fish

Lawn Pro

Footer Links 1

Footer Links 2