Yanmar 2QM15 Rebuild

[OwaDestiny]

Last season we discovered an oil leak at the rear main bearing seal. Upon removal of the main bearing housing with bearing and seal, I found that the main bearing was .001 of an inch out of the wear limit. This calls for replacement. But if one of the main bearings is out of limit then most likely all bearings on the crankshaft are bad too. So, I will be pulling the engine and rebuilding it this month.

I am asking all experienced mechanics for advice as to what items need mandatory checking and replacement for this engine? I intend on tearing down the engine to the main block. The head will be removed and sent to a shop for a valve job and valve seal replacement. What is the likely hood that piston rings will need to be replaced? I would expect that I need to hone the cylinder walls like any other engine so the rings can reseat, but this is not mentioned in the service manual. The service manual states that the fuel pump should be left alone. I intend on following these guide lines because the engine ran fine last season.

I don't know how many hours are on this engine because there is not a tach or chronometer on the boat. I have only two indicator lights high temperature and low oil pressure. I really hate idiot lights for any engine, car, boat, plane, etc. Therefore, I am looking for a source of gauges for this engine too.

Thank you all in advance.

[motion30]

replace the rings no questions I would most likely replace the pistons as well

[Chief Engineer]

Rings, valves, bearings, the whole enchilada.....have you priced the parts yet?

[OwaDestiny]

Chief and motion,

Thank you for your responses. I have priced parts via marinedieseldirect.com for the gaskets, main bearings, injector insulator, etc. What I have not been able to determine is what gaskets are included with the "engine overhaul" set, part number 724070-92605.

I will include two sets of rings into this list. I was hoping to be able to reuse the pistons and values if they measures to have minimal wear. This I wouldn’t know until I get into the beast.

Are you aware of any special trick to working on this engine? I have made most of the specialty tools and have standard shop tools for most applications. I will not be going into the transmission but I will be flushing and replacing the fluids.

Thanks again for you suggestions.
Brian