Dropped off TB2 at Sunset Marine, and discussed the problem with Head Mechanic Doug Mallas. Right now, the suspicion is that one or more of the fuel injectors were also damaged by the earlier salt-water-in-the-fuel problem, and may have finally given up the ghost. He thinks BRP will cover it under warranty, especially given the number of problems I've had, even if the underlying cause was not their fault. I'll keep my fingers crossed.

Took TB2 out today for a "real" fishing trip, rather than a boat test. Headed out to the Coronados again, looking for yellowtail and bonito. No luck there, but the weather was fantastic - partially cloudy, too warm for a jacket when the boat was drifting, very little wind.

Water was 62 degrees, almost no swell or wind chop, weak current. Lots of bait in the water, and I did see one spot of breaking fish early in the day, but, as is so typical of this time of year, they did not stay up long enough to get a lure to them. Did not meter any fish down low, either. Lots of seals and porpoise. A great day out on the water, even with no fish.

On the way in, I stopped at a couple of spots that had some obvious large bait schools and structure, and drove around, trying to figure out if the Raymarine Sonar unit's automatic mode was operating correctly. It appears as if there may be some issues with the automatic settings, regardless of the "digital" aspect of the sonar. While on the "Automatic Fishng" mode, the unit was not marking obvious bait schools (I could see them in the water), but by going in to manual mode and increasing sensitivity, they appeared. I suspect in automatic mode that there is some surface clutter cleanup logic tied to gain level that is causing these bait schools to be treated as surface clutter or noise. I'll call Raymarine next week to discuss.

But now the bad news - the boat ran great almost all day, but as I entered SD Harbor at the end of the day, the engine started missing, then would not run over 3000 rpm, and was surging/hesitating! At first I thought it might be the engine's failsafe mode (I think they call it SLOW), but there were no alarms going off. It was acting very much like it was having a problem with fuel line blockage, so I stopped the boat, pulled the hood, and looked at the inline fuel filter. It had clean fuel, squeezing the fuel primer bulb sent plenty of gas into the filter, so if it was a fuel problem, if was happening downstream from the inline fuel filter.

Idled in to the docks, and went home. I called Sunset Marine from the car to give them a heads up

Simrad called back, and was able to reproduce the problem. The bad news - a replacement motherboard would be required. Since the unit was out of warranty, the new board would cost around $485. Ouch! Unit was sent to me via UPS Ground the next day.

Got a call back from Simrad, they said the drive unit checked out OK! They gave me a couple of other things to check - whether or not there was any water damage to the controller (opened it up, dry as a bone), and some resistance measurements on internal connections inside the fluxgate compass (also checked out OK).

After I called them back with this news, we reviewed what I had observed, and the history behind the unit, including the hard-right turn that would occur after the unit got hot. They said they would attempt to simulate the problem by having the unit run overnight, and hitting it with a heat gun.

Called Simrad tech support in Lynwood, WA. They had me check the input voltage to the drive unit (checked out OK), and double-check the motherboard LEDs (still dead). Too bad, now it's time to take the drive unit off and send it to Simrad?

This was the step I was not looking forward to. Not that it's hard, just a bit messy.

The first step is to pull the steering wheel. This is the part I don't care for, as the automobile steering wheel pullers do not work on the boat's steering wheel without jury rigging something (see our auto-pilot article). But the wheel came off fairly easily, the rest of the work required to pull the SRD-12 drive unit was a piece of cake.

I put the steering wheel back with the the original Teleflex NFB cable drive so I could run the boat in the meantime.

Opened up the AP to try to figure our what is wrong. The unit continues to emit a continuous alarm tone when powered up, and the red status LED on the hand control does not light. Looked inside the SRD-12 drive unit, and the montherboard LED is not lighting up, either. It's supposed to blink to signal certain types of faults, there is absolutely nothing.