generator 2003 Windsor 7500 Onan not starting,

[danwegand]

how difficult is it to access and change glow plugs? 

[Ivan K]

It would depend on the engine but on my Isuzu it would be difficult to do without access from the top. See if you can get to them from the top opening, I suppose there is a removable access door on yours too.

I would check if they even get power, I find it unlikely for all of them to quit.

Edited November 21, 2022 by Ivan K

[jacwjames]

On mine I would have to pull the top off the generator also.  But that's not hard, while you have it off look at the belt, might be worth changing. 

[Doug and Nicki]

If it is an ONAN with Kabota engine, they are right on top. What makes you think they need changed?

[OhReally]

Some Onan generators get cantankerous and start but then stop shortly thereafter when the oil level is low. You might want to rule that out before going further.

-Jamie 

[MyronTruex]

I had to replace at least one glow plug years ago and changed all three at the same time. My generator is on a slide so getting inside is not difficult.

At 1000 hrs I did the recommended maintenance which was belt change, thermostat, and I can't remember the rest but the glow plugs have been fine since the first issue. 

So if you are close to that mark you might want to gather all the components for a full maintenance. 

[michaelivan]

Was it running and stopped, or just won't start?  One thing to check is the fuel level on the main tank.  On our Windsor, when the fuel level drops below about 1/2 full the generator won't run because of the fuel pick up location in the tank.

[tmw188]

When do the glow plugs activate? If you push to start top of switch or is it in the down position? I know pushing it down shuts it down, but before starting it seems to run the fuel pump just like in the normal start position?

[jacwjames]

This is right out of the manual

"Preheat is the period of time
prior to engine cranking when the glow plugs preheat
the combustion chambers. The time is automatically
varied by the genset controller on the basis
of engine temperature."

So if it is cold enough the engine won't start until the glow plugs have been activated long enough while holding down the control switch while starting. 

[tmw188]

1 hour ago, jacwjames said:

This is right out of the manual

"Preheat is the period of time
prior to engine cranking when the glow plugs preheat
the combustion chambers. The time is automatically
varied by the genset controller on the basis
of engine temperature."

So if it is cold enough the engine won't start until the glow plugs have been activated long enough while holding down the control switch while starting. 

Ok understand all that, but if you push down on the switch as if you were shutting it down but before you try starting it, it sounds as if it’s priming it also that’s my question?

[jacwjames]

From the manual

PRIMING THE FUEL SYSTEM
The fuel system should be primed after replacing
the fuel filter or running the genset out of fuel. To
prime the fuel system hold the control switch down
in its Stop position for at least 1 minute.

So if you hold the stop button down too long it may start to prime.  Just a guess. 

[Ivan K]

Holding the gen switch down before starting only runs the lift pump to get fuel to the mechanical high pressure pumps. Holding it up to start also runs the electric pump plus the controller decides whether and how long the glow plugs need to be preheated prior to cranking. Easy to confirm with a test lamp on one of the plugs.

[tmw188]

Good to know. I’ve serviced the Gen without having to engage that dedicated prime switch, now understand the reason for having that option. Thanks Jim and Ivan.