Your last generator Maintenance Run

[slckeys]

My 5k Onan failed to start this past outage.. Turns out the starter fuse blows every time power is tried to be transferred to start it. Gotta figure this out before winter hopefully.

Maybe it'll give be an excuse to finally pull the trigger on a 10-15kw diesel generator vs the little 5kw propane that it is now. It's wired to run everything in the house now, but really grunts when the hot water heater kicks on. But that and the water pump... Almost stalls the generator.

So... Anyone have any simple thoughts? Transfer switch works perfectly. Battery to start the generator sits at 13.x volts to fire it up. Don't see any corroded or broken wires. Could use spark plugs though. I'm thinking of tearing the starter out and finding something comparable? Thanks for any thoughts or ideas... Stumped.

 

[grsthegreat]

Did you leave tester on battery while trying to start it to see what voltage does. I know on older generac units the 5 amp glass would blow if either the starter had issues or the battery voltage UNDER LOAD dropped excessively. Also remove battery cables and ohm them out. Also at same time sandpaper connection point where ground wire attaches to frame.

 

[3930dave]

Great points grs. Green-fur grabs attention, but it doesn't take much oxide at all to cause headaches.

sic - not saying directly relates, but definitely do plugs. One of the "problems" with propane is both plugs and oil often look really clean, but have tons of hours on 'em.

Rgds, D.

 

[slckeys]

Thank you both.. I'll replace the plugs, and check the voltage on the battery. I'll see what my battery tester does in the load test. Never thought that could cause the glass fuse to blow. Good to know that!

 

[grsthegreat]

if the starter is beginning to go bad, that will also blow the fuse.

 

[slckeys]

Can I test the starter by just applying 12v to it?

 

[3930dave]

Can I test the starter by just applying 12v to it?

That will usually tell you if you have a locked rotor (mechanically jammed).

Starters going "off" can sometimes have weird current draws, seeming to spin, but drawing abnormally high current. Easier to assess if you have a known good starter. Chicken/egg, I know.

Start by comparing the battery voltage under starter load, with what voltage actually appears @ the starter terminals - that may help track down connection issues like grs was describing.

Rgds, D.

 

[ultrarunner]

Had a starter pegging the needle on draw and turns out a starter shaft bushing had worked loose and the mis-alignment the reason...

 

[slckeys]

That will usually tell you if you have a locked rotor (mechanically jammed).

Starters going "off" can sometimes have weird current draws, seeming to spin, but drawing abnormally high current. Easier to assess if you have a known good starter. Chicken/egg, I know.

Start by comparing the battery voltage under starter load, with what voltage actually appears @ the starter terminals - that may help track down connection issues like grs was describing.

Rgds, D.

As far testing the battery under starter load, I can't with the generator itself. Before the generator even tries to do anything, that fuse blows. This weekend I'll hopefully..

1. Disconnect battery and load test(battery is close to 6 years old come to think of it)

2. Put in new spark plugs

3. Double check all wiring more thorough

Thank you all for the ideas and what to check. I'll report back with any good/bad results.

This is hands down one of the most helpful forums I've been part of

 

[3930dave]

Had a starter pegging the needle on draw and turns out a starter shaft bushing had worked loose and the mis-alignment the reason...

Good example.

Rgds, D.