[SEL] Diesel Engine Starter With Oil Pump

[MaytagTwin at aol.com]

Hi Francis,
Yes, I think it is common for a diesel to have oil pressure before starting, 
or, if not common, very desirable.  

My Yanmar 155D small (15 HP, 2 cylinder) diesel tractor owner's manual 
suggests this starting procedure:  open fuel petcock, pull speed control to stop, 
turn on the electric switch and note the oil pressure light is glowing red,  
release the compression, crank the engine (electric starter) until the oil 
pressure light goes out and then, after closing the compression release,  advance 
the speed control whereupon it will start.  I do believe Yanmar wants an oil 
cushion between the bearing surfaces before that diesel starts knocking, and it 
does knock a little at start.  Having the compression released certainly makes 
it easier on the starter motor as the cranking time to get the oil light out 
is 20 seconds or more.

An old military surplus aircooled diesel generator set I have instructs one 
to release compression, crank until the oil pressure gauge reads normal, then 
give it compression and crank until it starts.  Again, oil pressure is 
desirable before running. 

I have some of the China diesels with oil pumps, and they want you to crank 
until you see the tell-tale oil pressure indicator pop up before releasing the 
compression lever.  These don't have gauges, just a little rod that extends 
from a springloaded piston/cylinder and receives pressure from the oil pump.  
When there is pressure, the little rod rises a quarter inch or so.  No pressure, 
and it drops back out of sight.

Regards,
Ron Carroll
Nokesville, Virginia

In a message dated 10/27/2005 12:34:21 AM Eastern Daylight Time, 
FRM8198 at aol.com writes:
Is this a common practice to pressurize diesel engine's internal  oil system 
prior to starting?  

Francis  Maciel
Santa Maria, CA