which cylinder is #1? yanmar 2qm15

[SEADANCE]

Hello All,
We recently have been trying to replace a head gasket on our raw water cooled yanmar 2qm15 engine. We were about to remove the rocker arms and push rods but were a little confused about being able to adjust the lash when we put it back together. We could not find the hash mark on the crankshaft pulley that is suppose to line up cylinder 1 with tdc. We also have hit a snag in identifying cylinder 1. The old 2qm15 manual says it is on the flywheel side but our after market manual states that all models except qm are on the flywheel side. It states that #1 is on the front of the engine closest to the crank shaft pulley. Does anyone know which one is #1 and is there a way to identify top dead center without a visible mark to indicate it?

 

[Bill Roosa]

Uber mechanic days

Well you're in the thick of it now.
Don't worry there has to be a way to time the thing. Can you find timing marks on the flywheel or crank pulley? That should lead to at lease finding them on the engine block.
In a last resort you can take out an injector and use a screw driver to feel the top of the piston to see when it is at DTC. Then look at the mark on the pulley/flywheel and find something (could just be the engine block bottom case mating surface!!!) that lines up.

After you get it all back together be sure to hand crank the engine to check the valve timing. One tooth off and you will bend a valve or crack a piston!!! Two complete turns of the crankshaft with no binding means you don't have a valve interfering with a piston.

 

[RichH]

If this helps .... the 2QM20 (and 3QM30) has its TDC mark on the portside front of the engine just in front of the oil filter mount. This is a mounted thick sheet metal 'el' bracket. held to the engine with 2 screws. The TDC mark lines up with a 'mark' on the 'base' of the crankshaft Vee Pulley.

Sorry, I dont have the drawings for the 2QM15 ... so there may be differences. the 2QM20 and the3QM30 both have the #1 cyl. at the 'forward' (not the flywheel) end.

 

[garylinger]

Looking at the Service manual for the 2QM15, it shows the timing marks on the camshaft gear and the crankshaft gear, located behind the timing gear case (front of the engine). It does not specify which cylinder is #1. I believe there is an online .pdf file for the service manual. If you can't find it and need it let me know. I may be able to point you to a copy.