Briggs and Stratton L Head - Low Compression

cpurvis

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Part of the head gasket is missing.
 

gibbywmu

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Right. I noticed after posting, and watching more YouTube videos relating to head gasket repair, that this was pretty much shot. I've got one on order from Amazon that will be here on Friday. I'm hoping this resolves the issue.
 

bertsmobile1

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FWIW I get a lot of mower gaskets from Lanni @ CoppergasketsUS.
They solved to continuing saga of inteks blowing a gasket a season
Even better fitting a copper gasket allows me to bypass machining the mating surfaces.
Looks like Briggs cuts them with a flycutter.
Some are quite good but a lot have machining swirls better than 0.010" deep and these seem to be the ones that blow a gasket every season.
 

tom3

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One thing I've done a lot with head gaskets is to give the gasket a good coat of aluminum paint on both sides, bolt together while the paint is still tacky. Helps with old engines with not so good surfaces etc. There are products for this but the paint seems to work fine.
 

gibbywmu

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Thanks Tom. Honestly, I'm not throwing any more money at this engine. Don't have any aluminum paint. Also, I don't have feeler gauges, valve spring tools, lapping compound, lapping tool, leak testers, etc.........so I'm not about to throw more money at this engine nor does it make sense. If replacing the gasket doesn't work, so be it. I paid $25 for the pressure washer and I'll sell it for parts if its still not running right. Just thought I would get as far as I could with the tools that I have.
 

Fish

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It is just a good idea to remove the wire at the coil, then test run. A bare/thin spot anywhere in the wire can cause arc-ing to ground to nearby metal, and cause rough running. The head gasket should be replaced, as it has lost some material from the first removal, and may not last long.
The head gasket on these l-heads is not as critical as on OHV models, so it is not likely your problem at this time.

I once worked on a small pressure washer that ran like crap, and a new coil was the only cure.
But I always take the time to make sure what the problem is before buying any parts, and suggesting others to do so.
So, while you have it apart, replace the head gasket.
 

nbpt100

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Did you put a straight edge on the new to you head to make sure it is flat? New head gasket is a good idea. I would also check the air intake tube and make sure it is tight. There are 2 screws that connected it to the intake and they can loosen. I have also seen these crack. They are now all plastic. Usually if that happens it will not run. But a tiny crack may cause the issue. Also I have seen them wear down from rubbing against the metal bracket the carb screws to. The oring needs to seat well there. If it is worn down it may be an issue.
When you inspect the plug is it black and sooty? Rich condition? Or is it whitish suggesting a lean condition?
 

gibbywmu

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Fish/NBPT,

Thanks for the advice on the arcing from the coil. When the new head gasket comes in tomorrow, I'll replace that, then remove the kill switch wire and see what happens. I don't see any nicks in the cable which could cause arcing to nearby metal, but of course not out of the question.

Yes I did inspect the plastic air intake. I actually removed the whole piece and inspected top/bottom for any cracks or fractures. It's in mint condition so that's definitely not the issue. I still think its that head gasket and when I removed it the 1st time it was pretty bad, so I tried reusing and of course it was worse.

After putting in a brand new plug, within minutes it was already black and sooty as you mentioned, so its definitely burning oil.

My other question is..........this had brand new engine oil that I put in a week ago..........now the oil is sooty and smells like gas. Is this because gas is someone leaking down past the piston because of the bad compression?
 

gibbywmu

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Hi Guys,

Well, I installed the new head gasket this morning and its still not running right :(. I'm really at a loss here. Looks like its still leaking some oil, and the plug gets pretty nasty after a minute or so of running rough. Not sure if its running rich or burning oil. No idea what else to look for?

Do these mufflers have gaskets, so if the gasket was bad it could be sucking air? Can't be the carburetor.......since that's brand new. No clue what else to look for here :(. Not willing to invest in compression tester or other tools. Will just likely scrap this engine.
 

tom3

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These little engines on washers really get a workout, high rpm and loaded about 90% of the time. Did the cylinder bore look smooth and shiny? Could be a valve guide is worn and sucking oil from the crankcase, letting combustion gas back into it. I'd probably buy a new washer much like yours and save the new pump for future use, those don't last long either sometimes. Look for a commercial series engine with an iron sleeved cylinder.
 
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