My guess, air in fuel lines.....
which you will need to bleed out before the motor will fire.
Sounds like you have a 2 cylinder (2 levers) motor. On my 3 cylinder Yanmar, the compression levers, are forward (I think) when the motor is under full compression. Check those to see if they are in the right position first. Maybe call Mack-Boring (Yanmar Distributor) to make sure.
Aside for the compression levels, any air in the fuel lines will cause the motor not to fire. I'll try to verbally walk you through bleeding the lines, but there is a video/picture explanation from another Sailnet member (ArtbyJody?) that explains with pictures, but I can't seem to find it. A Yanmar manual will also have diagrams.
- If you have a Racor or other fuel filter/waterseparator, you need to get the air out of that first.
- There are two screws on to of the Racor filter, a larger thumb screw and a smaller slotted screw.
- Unscrew the larger thumb screw and raise it. It is a small pumping handle
- Unscrew the smaller screw all the way. This is the bleed vent.
- Pump the handle until only fuel comes out of the bleed screw. This may take a few minutes. If you want to speed it up, use a small eye dropper and drip in CLEAN diesel in the bleed vent until you can't put any more in.
- Close off the pump screw and close the bleed screw.
- Go to the Primary fuel filter (on the motor) and crack the small screw in the center of the top of the fuel filter housing
- Locate the priming fuel lift pump on the motor and press it until you displace all of the air in the line. This may take a few minutes.
- When no more air comes out, close the bleed screw and go to the bleed screw just before the injectors.
- Crack the screw and repump the fuel lift pump until a steady stream of fuel comes out.
- Tighten the screw, clean up any diesel spill, and try to refire the motor.
You may have to rebleed the fuel line if the motor fires and then shuts down a few minutes later. Some fuel lines have a secondary high point in them where air can be come trapped. This trapped air has now been pushed to the motor and needs to be bled off.