721D HARD STARTRING

[CHARLEE475]

TAKES 5 MINUTES OF CRANKING TO EVENTUALLY START, AT THIS POINT COLD ENGINE WILL NOT START WITHOUT A JUMP.
I MADE A BIGGER BATTERY BOX TO HQNDLE A FULL SIZE AUTOMOTIVE BATTERERY I\ TO ACCOMODATE LONG CRANKING TIMES,
I AM CONCERNED I WILL EVENTUALLY BURN UP STARTER MOTOR.

 

[cpurvis]

721D is a diesel, correct?

Hard to start diesels are usually a case of the compression isn't heating the air enough to ignite the fuel. That's why the smaller ones have glow plugs or a grid to pre-heat the incoming air. When this is happening, there are usually puffs of white smoke (unburned fuel) coming out the exhaust.

Make sure the intake air pre-heat system is working.

 

[gone fishing]

TAKES 5 MINUTES OF CRANKING TO EVENTUALLY START, AT THIS POINT COLD ENGINE WILL NOT START WITHOUT A JUMP.
I MADE A BIGGER BATTERY BOX TO HQNDLE A FULL SIZE AUTOMOTIVE BATTERERY I\ TO ACCOMODATE LONG CRANKING TIMES,
I AM CONCERNED I WILL EVENTUALLY BURN UP STARTER MOTOR.

1) make sure you are using the glow plugs and if so check for power to glow plugs. 2) make sure you don't have any cracks in the fuel hose from the tank thru the inline filter and up to fuel lift pump on engine. 3) Observe that the fuel solenoid is pulling the fuel lever open on the injection pump when the starter is cranking the engine--if not check fuse. If you have compression and fuel with working glow plugs that unit should fire up in about 3 seconds.