unusual starting Yanmar
any help would be appreciated.
my 2gm is an original from 1982.
it has been running fine and I am the original owner
the filters have been changed regularly
this season when launched it started normally and ran for ~5minutes before violent shaking and stopping!
now it will not start at 1/4 throttle( were it always did) I can start it at 1/2 - 3/4 throttle it starts and runs smoothly when I let it warm up and try to throttle back to neutral it starts to shake violently and stop.
I have bled the system to no avail. It was suggested to try starting on one cylinder at a time to see if they are equal and they are.
any suggestions at what I can look at or what may be the problem