Scored Piston

[RoyM]

What is the date code on the engine? Is there any other damage like a scored rod or main journal?

[KE4AVB]

Pull the crankcase cover, remove the rod cap, and if the crankshaft journal has aluminum transfer then it was ran without enough oil.

[Az Shadeguy]

the date code is 130905
the crankshaft and the rod look very clean with no alum transfer
One thing I did notice when taking this engine apart was the bolts were not very tight
Like the exhaust bolts the valve cover bolts ,one of the head bolts.
Lots of oil all over the engine
I don't think anyone has ever taken it apart.

[RoyM]

That engine is still within the warranty period. Some had problems with the improper piston being installed, however now that it is apart the point is moot unless you are an authorized dealer.

[Arkie]

If I see a piston skirt scored I also check to make sure the block is not overheating from lack of air or coolant flow. (cooling fins clogged on a air cooled engine or weak coolant flow on a water cooled engine.
A aluminum piston skirt expands faster than surrounding steel and starts scrubbing on the cylinder wall as the engine overheats and if engine is at low rpm it will sometimes sieze the piston in the bore before the rod overloads and breaks and when the engine is allowed to cool the pistons skirt shrinks and engine will (may) free up, therefore a scored piston is not always a lack of lube in the crankcase.
If engine is spinning at high rpms when starts overheating and pistons skirts are expanding into cylinder wall the engine may usually destroys itself, but at low rpm it may just sieze (lock-up) and stop running. (and if you are lucky it may give you a chance to correct the overheat issue without severe major damage but the lifetime of the engine is usually compromised)
ONE piston such as yours scored all around on the skirt and operating at 3600 rpm's and low oil in the crankcase was PROBABLY due to lack of lube if it has the correct piston from the factory. (small emergency gens have a tendency to get operated w/o close monitoring of the oil level especially if they have the larger 6 gallon or more gas tanks. A small engine with the crankcase breather tube going into the air breather and severe crankcase blowby will consume lots of oil and no external oil leakage seen and not much oil smoke out the exhaust. (it's in the owners manual to check the oil level before each gas tank refill)

[KE4AVB]

Roy, Would you happen the affected date code range on this? I don't see anything noted when I pulled the engine info on the Power Portal site; may be a little hidden from my view though.

[Az Shadeguy]

Thanks for the replies.
I am not a dealer
These generators did not come with a low oil shutdown so I think they may have ran it low.
This is a Briggs Generator Model 030550 rev 00
The manual call for 20 ounces of oil

[RoyM]

Roy, Would you happen the affected date code range on this? I don't see anything noted when I pulled the engine info on the Power Portal site; may be a little hidden from my view though.

I don't recall specific date ranges. We saw some failures in walk power engines, Durabore pistons had been installed in Koolbore blocks. I am a little suspicious because the piston seized without any evidence of scoring on the crank journals. I would expect dirt ingestion to cause excessive cylinder wear but not an outright seizure. To the op, when was the unit purchased and was it being used for consumer or commercial purposes?