The manual says 20 seconds, but I wouldn't crank it for a straight 20 secs.
Short bursts or you will shorten the life of the starter.
I asked the local diesel
we were tipping a few at "The Dock
He's been working on fishing
boat engines, here in Beaufort
, forever and is old as dirt.
He said 20 seconds is way to long if the engine is to specs.
He has 1000 hp diesels with over 5000 hours, start up in 5 secs. cold!!
He said the main reason diesels will not start cold is air in the system.
When the fuel is hot from the engine running it has lots of positive pressure pushing out of various connections.
As the engine cools the fuel 'shrinks" causing negative pressure which sucks in air at every connection with a bad/old seal.
A couple things he would look for are:
~ Injectors...what does the manual say for hours until maintenance/rebuild
~ Connections - check for tightness.... every one from the injector back to the primary filter replace or install new o-rings where necessary.
~Most likely it's the feed to the pumps both high and low pressure....that will effect all cylinders
I asked him what could be done if those things didn't work.....
Smart ass said:
"Live with it... buy a back-up starter... "
A man of few words....I bought him another beer