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Yanmar 2QM15 Rebuild

23K views 21 replies 10 participants last post by  dreuge  
#1 ·
Hi,

In early July, I came to my boat after being away for three week and found the engine seized. It was locked up solidly, in that it would not budge even a little bit after soaking the cylinders with Marvel Mystery oil for several days. It turned out to be a blown head gasket which let salt water into a cylinder.

I hauled the engine out with the boom and rebuilt it for a cost of only parts and machine shop work. The engine is back in and is working great. I have posted photos online if anyone is interested.

Yanmar 2QM15 Rebuild - a set on Flickr (www.flickr.com/photos/dreuge/sets/72157631067396554/ )

Unless you live near a Yanmar distributer, knowing which part numbers to order can be time consuming and costly. I include my list below in order that it may help someone down the road.

My total cost was about $825.

Machine shop work

Cylinder head work $300
Honing piston rod bushings to fit piston pins $40

YANMAR 2QM15 PARTS
Price quote from Mastry Engine Center


Gaskets

head gasket (124060-01331) [$28.79]
valve cover gasket, o-ring type bonnet (124060-11311) [$8.47]
oil pan sump gasket (124060-01743) [$16.26]
exhaust manifold output gasket (124701-11911) [$9.15]
exhaust manifold Adj. gasket (124770-13131) [$1.87]
exhaust flange gasket (124770-13171) [$27.43]
engine zinc cover gasket (124450-11681) [$1.53]
thermostat gasket (104211-49160) [$1.36]
exhaust manifold forward flange gasket (124770-13181) [$9.00]

Engine parts
piston rod bearings (124060-23300) [2@$13.38]
piston w/ rings (724060-22722) [2@$86.37]
piston pin bush (124060-23910) [2@$5.08]
cylinder liner (724070-01900) [1@$111.77]

Other Parts
zinc (27210-200300) [2@$3.60]
zinc packing (23414-250000) [2@$0.85]
thermostat (124770-49200) [1@ 27.10]

Misc. item
Lubriplate #105 assemble lube
(coating piston, rings, piston pins, bearings) ~$7
Copper Cote gasket spray
(for head gasket and copper exhaust gaskets) ~$5
Permatex form-a-gasket #2
(gasket dressing for other gaskets and hoses) ~$4
 
#7 ·
I want to add another point regarding Yanmar exhaust mixing elbows.

The 2QM15 service manual lists the part numbers for the two mixing elbow options(see pages 11-10 & 11-11) . Part number 124070-13500 is for the downward angled elbow. The U-type mixing elbow option is part number 124070-13520.

The Yanmar list price for the part number 124070-13520 is $186.26. There is an option for a cheaper (both price and part quality) yanmar mixing elbow. Yanmar part number 128270-13600 which lists for $147.16.

I was reluctant to go with the cheaper mixing elbow because I was told the cheaper one last only a year before needing to be replaced, and in the long run one can save $$ getting the better unit.

I search around and found that HGE manufactures the the better U-type mixing elbow. The part number is HGE3520. One can buy it online for about $70!

See "www.mmiseattle.com/e/manifolds_e_hge_yanmar.htm" or "bpi.ebasicpower.com/c/YAN-D-EXH/Exhaust%20Parts%20for%20Yanmar%20Diesel%20Inboards".

I purchased one from MMISeattle (great folks), and it came with a 3 year warranty!
 
#10 ·
Dreuge,
Thanks for great post. I have a similar set up with a 30 year old Yanmar 3GMD and will be looking at having to do the same in the not to distant furture I am sure.

Did you notice any changes in exhaust or operation before the engine siezed up?

I get some white exhaust (steam?) when I run my direct sea water cooled engine and am wondering if it is sea water entering the cylinder through a bad head gasket. Thinking maybe somtime soon I should pull the engine and spilt the head and block, clean all the cooling passages, replace head gasket.

Also, I have been flushing with fresh water after use, maybe buy a little more time out of her.

Regards
 
#12 ·
I just purchased a 2QM15 to replace the Atomic 4 in my boat. I received the Parts List and the Service manual with the engine (1977) To answer Banjo Boy's request for part numbers this is what I have;
Oil Sensor 124060-39451
Coolant Sensor 46150-004530 replaced with 127610-91350 (200 degrees)
Hope this helps
 
#19 ·
Dreuge,
Where the fuel injectors go into the head, there are several washers, packing, and an o-ring. It looks like you may have removed these to clean the head. Did you install the old or install new? If you took these parts out, was that difficult?
Regards