Diesel generator starting issue

[motion30]

I have a westerbeke 8K diesel generator and has developed a problem while starting. The starting procedure is to hold the switch for the glow plugs for 10 seconds or so and then hit the starter switch. The problem that has just developed is when the motor starts it barely wants to run for the first 15 seconds or so then it seems to straighten out and run normally for hours. Power production from the generator is fine. This problem just started a few days ago and no work has been recently performed just looking for a direction on where to start looking

[Sailmonkey]

Are your glow plugs working?

When you’re operating the glow plugs can you hear the electric fuel pump running?

I’d start with the glow plugs, be sure they’ve got voltage, and that each one has continuity.

Then move to fuel if the glow plugs check out. It’s possible you’ve got an air leak into the fuel that takes some time to clear out.

[Scott Berg]

In order: Verify that the preheat/prime relay is working (using voltmeter): then verify that the fuel pump is getting power (same voltmeter); verify that fuel pump works from direct 12v connection; then check the glow plugs for power (same volt meter). If they have power check resistance (pull one for best reading; should be 1-6 ohms or so... one of these is probably it.

[Wotname]

I concur with Sailmronkey, check to see if all the glow plugs are working - one or more may have failed.

For a quick and dirty glow plug check, try putting the glow plugs back on immediately after starting (but during the first 15 seconds of poor running). If the engine immediately picks up, then perhaps it isn't a glow plug issue, rather perhaps a low compression issue. If so, always start with the easiest checks like valve lash etc.

[motion30]

Yea I was thinking glow plugs it's a 3 cylinder so should not be a big deal to check. If the glow plug is good the terminals will have continuity through the terminals yes?

[Sailmonkey]

Originally Posted by motion30

Yea I was thinking glow plugs it's a 3 cylinder so should not be a big deal to check. If the glow plug is good the terminals will have continuity through the terminals yes?

Correct, but you’ll need to remove the bus bar connecting all the plugs and measure continuity to ground for each one.

Check for voltage before going this far though

[Mikado]

Originally Posted by motion30

I have a westerbeke 8K diesel generator and has developed a problem while starting. The starting procedure is to hold the switch for the glow plugs for 10 seconds or so and then hit the starter switch. The problem that has just developed is when the motor starts it barely wants to run for the first 15 seconds or so then it seems to straighten out and run normally for hours. Power production from the generator is fine. This problem just started a few days ago and no work has been recently performed just looking for a direction on where to start looking

I have a Westerbeke 7.6 BTD and had the exact same issue. Turned out it was picking up a small amount of air at a fuel fitting. Once it started it barely ran for 10-15 seconds while it burned thru the accumulated air. Once it got past it then it would run perfectly until the next time that I started it cold.

Good luck,

Jeff

[motion30]

Jeff
I will look at the fuel fitings. Damn thing vibrates enough to shake anything loose

[Lepke]

When you start most generators, pressing the start button bypasses the coolant temperature and oil pressure safeties. Releasing the start button transfers the run condition to the safeties. A short or loose wire to the sensors or a weak sensor can also cause the problem.
But an air leak is where I would look first. Air entry into the fuel system while stopped can allow the fuel to drain away from the injector pump. The engine starts on the fuel in the pump and then the pump receives the air. Because air compresses, fuel in the injector line doesn't have enough pressure to allow the injector spray to overcome the thick, condensed, air in the cylinder. You get a partial ignition or no ignition at all in that cylinder.
Injectors I know have some mechanism to close off the injector from the ignition as soon as injection is complete. Usually spring closed needle valves. Without proper pressure the valve either doesn't open or open all the way.

[transmitterdan]

On our Westerbeke I have to hold the glow plug switch engaged while cranking the engine. The glow plug switch bypasses the oil and temp switches so the fuel can flow during starting. If I let go of the glow plug switch too soon after it fires the engine stops.

[Mark Thurlow]

me thinks you are too warm a place for real glow plug issues!

Air leak, certainly a bleed will sort this out.

[motion30]

Originally Posted by Mark Thurlow

me thinks you are too warm a place for real glow plug issues!

Air leak, certainly a bleed will sort this out.

I am thinking an air leak as well. , as the problem has gotten worse. I'm going to try to check it out tomorrow. These westerbeke 8K generators are supposed to be self bleeding do they have electric fuel pump

[Sailmonkey]

Originally Posted by motion30

I am thinking an air leak as well. , as the problem has gotten worse. I'm going to try to check it out tomorrow. These westerbeke 8K generators are supposed to be self bleeding do they have electric fuel pump

They will self bleed, but is the leak is far away from the generator there could be quite a bit of air in the line.

[motion30]

Follow up..
Finally got the motivation to take the sound shield apart, there was diesel fuel on the bottom of the enclosure. So i tightened a couple fuel clamps and checked everything else ,everything seem tight. Still no change in the starting issue. So I cleaned up the mess then I went down in the bilge again today and tighten the clamps a little more and the three fittings that come out of the fuel injection pump. that was the issue. It starts right up there with no hesitation there runs great I'd like to thank everybody for their invoice and happy New Year's to you all