Generac Starting Problem

[Rook]

My Coach has a Generac Diesel Generator. It barely starts, even with a full charge of the house batteries and plugged into shore power. If the batteries are down a bit, then I have to use a jump start from my Toad to get it going. I measured the voltage right at the starter solenoid and it is 13.4 volts not under load. As soon as I push the start button, the voltage drops to 7.8 volts and the starter barely will turn. I found that the heavy size #2 battery feed cable does not come directly from the house battery bank. From the battery bank, it goes to the 12V Distribution panel, to one side of the battery boost relay, then through the Battery Disconnect Relay, then through a 150 amp circuit breaker, then to a terminal......and then it runs about 30 feet to the Diesel starter solenoid through the #2 cable. I have measured the resistance of all the possible places that I could be loosing the 6 volts under load and found no suspects.

Anyone had a similar problem and found a solution? Rook

[srydve]

I had a similar problem on my generac, I did not measure load voltages but did clean all the junction points I could find to no avail. I jumped 12 v. from my good chassis batteries directly to the starter and found it would still barely turn over. It was a bad starter. I replaced the starter, not a lot of fun to change, and it's been good since. Good Luck.

[Rook]

Thanks Dave, checking and the cleaning of corroded contacts, especially the generator ground connection, was next on my list of things to try. I hadn't thought that it might be a bad starter....or perhaps worn brushes in the starter. The former owner said it used to start easily.....so something has changed. Changing that starter looks like a "lyng down on your back" job and I'm too old and stiff for that stuff anymore. Rook