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Just got this older (green) Craftsman, with an 18hp OHV briggs, 31P7770299E1 (has oil filter) Finally got it to crank. But man O man O man, when it did, it blew the PCV tube off the breather, and soaked the side of the engine and the front tire with oil.
I had checked to see if it had oil in it first, but didn't really look at the level. Well, it had too much in it. Way too much. Like an inch above the full mark. So, I sucked some if out, down to the right level, and cranked her up again. And It was still coming out like crazy.

Any other hints before I remove the head? I'm thinking it's a head gasket. But would like some feed back first.

Yes you a lot of pressure building up in the crankcase. Very well could be the gasket. Might as well dive into it.

Did the oil smell like gas or was thinner than normal ?

Drain the oil, refill with the correct amount and try again.

If the problem isn't resolved, THEN start looking for mechanical problems. Start by checking the crankcase ventilation system. I don't see how a blown head gasket can pressurize the crankcase.

cpurvis said:

Drain the oil, refill with the correct amount and try again.

If the problem isn't resolved, THEN start looking for mechanical problems. Start by checking the crankcase ventilation system. I don't see how a blown head gasket can pressurize the crankcase.

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I removed the head. And the gasket, to me, didn't look too bad. It didn't look great. But I didn't see any breaks in it. The top of the valves weren't oil soaked. Which mean the rings aren't bad. Thanks goodness.
$10 for a new gasket. New oil and filters. Which it was going to get anyways.

The PCV wouldn't be stuck open, would it?

Boudreaux In Eunice La. said:

Yes you a lot of pressure building up in the crankcase. Very well could be the gasket. Might as well dive into it.

Did the oil smell like gas or was thinner than normal ?

Click to expand...

I dove.

The oil had a little fuel smell to it. But mostly smelled like oil. But then again, I had some gas on my hands from trying to crank it.

cpurvis said:

Drain the oil, refill with the correct amount and try again.

If the problem isn't resolved, THEN start looking for mechanical problems. Start by checking the crankcase ventilation system. I don't see how a blown head gasket can pressurize the crankcase.

Click to expand...

A Blown head gasket will let compression into the valve rod valley and go straight into the crank causing pressure there and sometimes out of the carb..........

(But I didn't see any breaks in it. The top of the valves weren't oil soaked. Which mean the rings aren't bad. Thanks goodness.) Your post.

The break on those are on the block side of the gasket. It will be a very small area on the skinny part between the cylinder and valve rod valley. When you take the gasket off the block and turn it over there she be ~!~!

Remember to torque the head to specs.

Boudreaux In Eunice La. said:

(But I didn't see any breaks in it. The top of the valves weren't oil soaked. Which mean the rings aren't bad. Thanks goodness.) Your post.

The break on those are on the block side of the gasket. It will be a very small area on the skinny part between the cylinder and valve rod valley. When you take the gasket off the block and turn it over there she be ~!~!

Remember to torque the head to specs.

Click to expand...

Yeah, that's the side I'm talking about. It didn't look good. That's for sure. But nothing like I was expecting. Oil was shooting out of the PCV tube like a foot, the first time I cranked it. So I was expecting a complete tear in it, with like a big gap. But then I pulled out enough oil to put the level at the right spot. And the amount coming out, was significantly reduced. But still coming out. There should only be air coming from that tube.

BTW, I've only had like two sips of coffee. At this point, I may not even be talking about the same mower. he he he he he (que a cute coffee smiley)

hrdman2luv said:

Just got this older (green) Craftsman, with an 18hp OHV briggs, 31P7770299E1 (has oil filter) Finally got it to crank. But man O man O man, when it did, it blew the PCV tube off the breather, and soaked the side of the engine and the front tire with oil.
I had checked to see if it had oil in it first, but didn't really look at the level. Well, it had too much in it. Way too much. Like an inch above the full mark. So, I sucked some if out, down to the right level, and cranked her up again. And It was still coming out like crazy.

Any other hints before I remove the head? I'm thinking it's a head gasket. But would like some feed back first.

Click to expand...

just this statement alone tells me it was not the head gasket that caused the oil to blow out the pcv........either there was fuel in the oil from a bad carb float or someone added too much oil or there was water from sitting outside mixed in. The piston with good rings just paddled through the excess oil and pressurized it.

willys55 said:

just this statement alone tells me it was not the head gasket that caused the oil to blow out the pcv........either there was fuel in the oil from a bad carb float or someone added too much oil or there was water from sitting outside mixed in. The piston with good rings just paddled through the excess oil and pressurized it.

Click to expand...

What chu talkin bout Willis ? You mean I over did it? I Went too far? Done way more work than was necessary?

You're probably right.

Lying in bed last night, I was thinking about this. The first time the oil shot out of that tube, there was way too much oil in it. So I took just enough out. But, there was still oil in the tube, PCV etc etc. Which was probably clogging up that entire little PCV system. The 2nd time, it only ran for a few seconds. I'm thinking if I'd have let it run a little longer, it might have cleared up. I should've taken the tube off the carb, pointed it down into a drain pan and keep feeding gas to it, so it would've kept running.

Now, today is Sunday, and I can't get a gasket until tomorrow.

yea, sometimes I wish that home depot or lowes had a parts department for small engines.....at least they have better hours of accessibility than the mower shops around here in jersey.......they never seem to be open when you need them too

Boudreaux In Eunice La. said:

A Blown head gasket will let compression into the valve rod valley and go straight into the crank causing pressure there and sometimes out of the carb..........

Click to expand...

You're right. I was thinking about a flathead.

Found a good used head gasket and put it on. And that seemed to have solved the problem. All that's left now is the carb rebuild.

C Purvis I did that one time posting on another forum. I jumped in and said something about a valve cover not being on 6.75 HP engine. One guy said I was out of date on my engines and sent a link to the mower. A intek with OHV.

I crawled and ate crow. Well the guy never posted a number or NADA Just Briggs and the HP. He did mention a valve cover so everyone, Besides me thought is was a OHV.

Well in a later post he mentioned the spark plug came off with the valve cover. Lo and behold it was a L Head engine like I thought. My prognosis was spot on.

So yep I did the same thing, but It had a ironic twist to it..