Mike Schrage writes,
This winter I replaced the fuel lines on the generator. As one thing typically leads to another, I ended up replacing the fuel pump as well. The replacement fuel pump directly from Cummins/Onan is $400+. After a little searching around, I found a more reasonably priced replacement – a Facet Electronic Fuel Pump; Model number 477060 (12 volt; 2.75 – 4.0 psi). You can find it here: http://www.yachtsupplydepot.com/mechanical-supplies/fuel-pumps/face…
After I wired it up to the same place the old pump was wired to (there’s a single wire that goes to a resistor in the control head) and hit the the ignition switch, I didn’t get any fuel flow. I checked the pump with a vacuum gauge to verify it wasn’t working. To determine if the pump worked, I wired it directly to the hot post on the ignition switch – it immediately started running.
With some assistance from my handy and helpful boat neighbor and fellow Commander owner Ron Sherman, we began to do some more trouble shooting and determined that the voltage at the resistor terminal was 10.3v while the voltage at the ignition switch was 13.5v. Apparently the pump needs more than 10.3v to operate. (Ron also helped me determine that the oil pressure switch wasn’t causing any problem.) At that point, Ron and I called it a night.
After sleeping on it and reviewing the service manual (which can be found in the Library section on this site) I decided to send Mr. Lee Dahlen of Glassic Boatworks ( www.us21.siteground.us/~glassicb/) a text at (704)287-3914. Within minutes he gave me a call and helped me continue to diagnose the problem. After sending him a picture of what I was looking at, he reviewed a wiring diagram and began to zero in on the issue. He had me measure voltage on another terminal coming out of resistor. That terminal had 11.5v at it while the engine was cranking (and only when the ignition switch was on.) His suggestion was to wire the pump to that post on the resistor. After doing that, I put the vacuum gauge on the pump and flipped the ignition switch – it worked!
After some cranking to get fuel pulled through the line, the generator sprang to life. One more item checked off the spring commissioning list.
A huge THANK YOU to Ron Sherman and Lee Dahlen for their assistance with this. Lee’s “blind” diagnostic work and talking me through the process over the phone to bring this one home was most helpful! His reach knows no state boundaries.
1971 35′ Commander Sports Cruiser**
**You can read Mike’s original post at the Commander Club website.