Yanmar 2qm15 - How Far to Strip it Down ?

[Redbeard33]

I have a 1980 Hunter 33 with a 2qm15 yanmar, it has cosmetic issues one would expect from a 30 year old engine but runs strong and hasnt given me much fuss, however I plan on taking this boat pretty far and want it to be extremely dependable so I plan on pulling the engine this winter and repainting as well as replacing the obvious parts (filters, impeller etc.) and replacing parts that I would want spares of anyway (injectors, thermostat, fuel lines, belts)

With that plan being the baseline that I think I can get away with, how important would it be to get a "valve job" and get the cylinders bored with new rings, this is without a doubt much more effort and expense that I would avoid if possible.

The history of the boat is that it has been a weekender that hasnt left the ches. bay so hours are pretty damn low (still unknown however due to non functioning hour meter) but it is still 30 years old

So from prior experience does this seem like a "can of worms" or something that should be done for an engine of this age regardless of if its currently problem free?

[Arch Stanton]

I have the same engine in my SJ28.

Haven't had to work on it other than standard maintenance.

I scanned the complete (non-copyrighted) service manual into a .pdf. If you want a copy let me know and I'll PM you think.

[Redbeard33]

Also i plan on getting a part kit for this engine for $420, it would include:

Lube Oil Filter
Fuel Oil Filter Kit
Full Gasket Set (3)
Air Filter Element (1)
Injector Washer
Set of Zinc(s) + Gasket(s)
Can Engine Paint
Set of Belt(s)
Lift Pump + Gasket
Water Pump Impeller & Gasket
Parts & Service Manuals
Coolant Treatment (2)
Fuel Injector (4)
Marine Diesel Fuel Treatment
Fuel Bleed Screw & Washer
Thermostat & Gasket
MACK 726 Dry Box
Water Pump Seal

Is this a fair price, and what else would you include?

THANKS!

[djmarchand]

Redbeard:

Do these simple tests:

1. Start the engine cold. If it starts easy with just a few seconds of cranking then the compression is ok and the injectors are probably ok.

2. Check for an oil sheen on the water immediately after startup. If none, then the injectors are definitely ok.

3. Open the valve cover cap- where you add oil, and put your hand over the outlet. If you don't feel pulses of exhaust then the compression and valve guides are ok. This test is not really necessary if #1 is good.

4. Run the engine at wot in neutral for a few seconds. Does it hit rated rpm plus a hundred or two. This tells you if the governor is ok.

5. Once you determine #4 is ok run the boat at wot for ten minutes. Does it reach rated rpm? Does it overheat? Does it make a lot of black smoke? There are several reasons for not being ok but probably the most common is a plugged exhaust elbow- replace.

If all of these tests turn out ok, you are probably good for thousands of hours of uninterrupted service from this engine.

BTW the spares kit is a good price for what it covers and the injectors are worth the price of the kit, but you don't need 4 injectors. Two will do and make sure that these are well protected from rust.

David

[bljones]

Store the injectors in a jar of diesel to keep them fresh. djmarchand pretty much nailed the diagnostics- if you don't have any symptoms of engine unhappiness, pack the spares and change the consumables and run 'er.

[Boracay]

For mine the question is - Can you survive without an engine?

If you can, and you're happy to continue under sail and get a 30 year old engine fixed in a far away land then what you're planning looks fine. If cash is limited this could also be the be the best way.

If you're not so happy about the idea, have a significant other who has a few doubts or have marginal diesel mechanic skills and cash is not a major consideration then why not consider a new engine.

Extended cruising means extended engine use, so every part of your old engine is going to be tested.

I didn't see them on the lists but checking that your fuel tanks are squeeky clean, that fuel hoses are near new, the battery is sound and starter wiring is good is also necessary.

I had an old rusty Yanmar a long time ago that I had overhauled. Made no difference. An expensive waste of time and money. Same experience more recently trying to fix an old Ford. The mechanic who got it for free found bent pushrods.

Fixing old engines is a mugs' game.

[Tellie]

Also get the oil checked. It can tell alot on an otherwise good running engine.

[svrodeorm]

What I would add to the spare parts list: (for extended cruising to 'off' places)


An alternator
a starter
a head gasket (at least if the engine has +20 years and/or + 4000 hours.

Alternatively change them before you go and keep the old, but functional ones, as spares.

Also, depending what kinda/make the engine is, consider keeping several spares for everything that's in the 'marinisation' part of the engine. Most small diesels are more common than most of us think in far away places.... tractors, generators etc.