Bad oil analysis

[winstonwilliams]

I have a bad knock in my 502 Mercruiser so I pulled some oil and sent it off to get analized and this is what they said:

Wear was well above average in the first sample from your Mercruiser. The high aluminum is
likely from the upper end, while lead and tin are from the bearings. Iron can be from any steel part. Silicon
may show an abrasive contaminant in the oil, or with coolant it may be from coolant or cooling water. Our
universal averages show typical wear from this engine model after an oil run of ~30 hours. We suggest​

having someone take a close look at your engine. Things don't look very good from here.

attached is the full report

 

[earthmover17]

Sorry Winston. Top end troubles might have not been so bad but they are saying you might have bearing issues. Bearing issues = motor pull.

Jack

 

[JeffMendenhall]

Winston, Putting my old mechanic hat on from years ago, they are right on the mark. Your levels indicate bearings. The iron could be from connecting rods or crankshaft if it is a pistion connecting rod bearing, but it can also be from a journal bearing on a crankshaft main bearing that is spinning. The knock you describe sounds like a connecting rod banging around. Get it checked before it blows.

 

[winstonwilliams]

Yeah now I need to figure out if I should rebuild or repower. Both of which sound expensive!

 

[Scottzzzy]

either way sounds like an expensive decision! Sorry to hear that.:smt089

How long did it take them to get your report back to you on the oil sample?

 

[winstonwilliams]

It was fast! One week from the time I mail the sample off they emailed me the results!

 

[CIC25]

Sorry to hear that bad news, Question what motor oil do you run, not that it anything to do with this.

 

[tobnpr]

Don't know how many hours you have on them, but they are fifteen years old. Did you send in an oil sample on the other engine? Perhaps not far behind.

 

[winstonwilliams]

This boat only has a single 502 so I guess I am thankful that I dont have to replace two motors. One is going to be bad enough!