Briggs and Stratton L Head - Low Compression

[gibbywmu]

Hi All,

This is actually an engine on a pressure washer. I was hoping that someone having experience in repairing B&S L Head Engines could provide on insight on my issue, before I decide to just scrap this engine for parts.

I have a Husky Pressure Washer with a B&G L Head Engine. The Engine Model is the 10L902-0010. Pretty much a standard B&L L Head Engine. The cylinder is low on compression, around 80psi. It runs very, very rough......not to the point that it stalls, but very poorly. Changed plugs and still did not resolve.

Background Info - Purchased for $25 at a local online swap sale. Ran ok for about 5 min, discovered it needed a new pump. Purchased for around $70. Purchased new carb (kit w/ diaphragm and all), new air filter, sparkplug, and fresh engine oil. Started running funny, realized sparkplug hole was stripped. I definitely did not do this, so purchased another head on Ebay for $10. Inspected cylinder and seemed ok. No knicks or pitting. Piston looked ok with normal carbon buildup. Intake manifold looks ok. Did not disassemble, but no signs of cracking.

The head gasket looked ok, but not sure how to tell if its 100% ok? Wondering if this is the main issue? I see they are very inexpensive, around $5 on Ebay. I'm definitely willing to take the risk for that amount.

I don't have any sort of leakdown testers, so I won't be able to tell where the air is coming in at? I'm thinking its got to be sucking air somewhere.

I don't mind taking the head off again if someone needs to see a picture of the head gasket.

Any suggestions on where else the problem is? Or am I right and thinking the head gasket is not ok?

 

[cpurvis]

Re-using head gaskets is generally not a good idea.

While ebay may be a good source of cheap parts, I don't consider it to be a good source of good parts. Too many counterfeits around.

I believe that engine uses o-rings to seal the intake tract.

 

[tom3]

Could be an easy start engine? That would have a compression release that works up to a certain rpm to reduce the pull needed to start, give you a low reading on the test. I'd suspect the diaphragm carb has a warped base and the new diaphragm can't seal up on that.

 

[gibbywmu]

Tom,

This is not the "Easy Start" or "Ready Start" B&S Engine. I don't believe any of the L Heads have that, its only on the OHV Engines. Regarding the carb, as mentioned, I put a NEW carb and NEW diaphragm on this. I can't see the carb being an issue.

Should I just try and put a new head gasket on? Only $4 on Ebay for new.........

 

[Telesis]

I highly doubt it's the head gasket but it is cheap enough to put a new one on to rule it out. When you did the carb, did you clean the screen on the bottom of the plastic pickup tube? Also, I'd consider removing the pump and checking how the engine runs without a load. I know you put a new pump on but this way you'll get a better idea how the motor is running. IMHO, 80psi on these 4 cycle L heads should run just fine. I have 5 pressure washers in my shop right now, that all had bad pumps and the motors ran badly due to pump issues. The pumps have bad check valves, or the unloaders have blown an "O" ring or are frozen up due to corrosion etc.etc. Point is, isolate just the motor first.

Keep us posted!

 

[gibbywmu]

Telesis,

Thanks for responding! Not sure if you missed it, but there was no cleaning of the carb necessary. I put a brand NEW carb on this motor, which also contained a brand new gasket and diaphragm. Lets rule out the carb . We can rule out the pump as well, the pump is brand new and that was also removed prior to testing the motor again. W/out the pump, the motor ran like garbage. It stayed running, but ran awful. Wouldn't stall out though.

I'm going to go pull off the intake manifold right now and search for fractures/cracks. Didn't appear to have any, but of course couldn't see the bottom side.

 

[Scrubcadet10]

I think 80 pounds is about right, looking at the cam from this engine, it had a compression release.. Might ought to check valve clearances.

 

[gibbywmu]

Hi All,

Here are some more pics from today. I removed the intake manifold and inspected, it was fine. No cracks or fractures. It may be this head gasket, its not in the greatest shape and some oil was coming out of the bottom of the cylinder head. Piston, Cylinder, and valves look ok. Both valves seat properly after turning the flywheel to inspect.

What are your thoughts on this head gasket?

 

[Fish]

Unplug the kill wire and then try it.

 

[gibbywmu]

Fish,

After watching more You Tube videos, I'm pretty sure that head gasket is shot.........especially considering oil was leaking out the bottom of the head. Do you really think it could be the kill switch? The switch is on the front cover, which has 2 leads that the wires connect to. I know closing that switch of course kills the engine.............but if that switch isn't even connected at all, how could it be that wire is causing it?