Are you running the glow plugs? Think the 2305 is probably like my 4010. You have to put the range lever in L or H; turn ignition key all way to "start"; count for about a count of 6; move range lever to N. Should start instantly. If you haven't regularly been doing this, and the engine cranks a bit before starting, you're not really using the glow plugs. Even on my 25 year old Benz, glow it, and it starts instantly.
Another option to using the range lever is to pull up the PTO button, go to "start", release the button after 6 seconds. In summer, it's only 2 seconds needed.
You CAN find a glow plug position on the ignition switch by putting a test light on a glow plug and run to ground. You'll find that the light comes on half way between "on" and "start". Trouble is, without the light, you cannot consistently find that position. So, we have to trick it with the range lever or PTO button.
Ralph