Re: Yanmar 2gm20f
Not a mech, so remember advise given is worth about what your paying for it.
"Is it any chance to have fuel pressure for second but not for the first injector?"
After making sure all fuel line fittings are tight and then adjusting your throttle governor screw (to reduce rpm's)I'm thinking could be
symptoms of troublesome injection pump.
Would sure be nice to find out some history of who last worked on
this motor, and what they did...maybe yard mech or previous owner?