DF150 odd start

[Harper]

I have an '07 DF150 with about 120 hours. I've never had a single issue with the motor. But a strange thing happened on a startup this past weekend. It wasn't the first start of the day, but the engine was cold. We had been anchored at the same fishing spot for about five hours. I always let the engine go through its diagnostics before cranking, and did so this time. When the key is turned on, the four warning lights come on, alarm sounds, lights and alarm go out, tach indicates about 1100 RPM, then back to zero, then I start the engine. When I did that this time, the engine caught right away, but went immediately to 2000 RPM, lingered there for a couple seconds, then died. I turned the key off, then back on and I let it go through its diagnostics again, and cranked again only to experience exactly the same thing. So I turned the key off and cranked it immediately without letting it go through the diagnostics. This time it acted normal and never gave me another problem. It ran fine all the way back to the ramp. I did not turn it off and try to restart again, so I don't know whether it would have had a problem again. When I later ran the engine on the muffs to flush the salt, it started normal, after going through the diagnostics as usual. Hopefully it was just a starnge, one-time hiccup.

[boats.net]

Sometimes things like that happen, no explaination.

[Harper]

still doin' it.....

My DF150 is still having the starting problem. Happened quite a few times on my last outing. Pulled the IAC, thinking I would start there. It checks out fine. I just read on another forum that this is not that uncommon, and seems to be an issue with a fused white wire that goes directly from the battery positive terminal to the ECM relay, and/or could be battery cable connection issues. Seems the ECM is very sensitive to any slight voltage drops and will shut down if it sees anything that it doesn't like. I'll be checking all connections on the battery cables and that white wire and fuse. Hopefully will find the problem.

[drifterny]

Same thing has happened in the past with mine.

I think it has something to do with fuel in the system.

I dont think its a big deal as I have over 1000 hrs on my 07's and they run great.

Actually thinking of upgrading to 175's

[Harper]

It's not a fuel problem. It's the sub battery cable, a fused white wire directly from battery positive terminal to ECM/main relay. Problem is, boat dealer did not connect the sub battery cable to the battery, but somewhere else. I have yet to figure out where. Nor can I locate the 15 amp fuse associated with the cable.

[Harper]

Well, I found where the sub battery wire is connected. I had forgotten that there is a terminal block in a compartment in the transom. The attachment is there, but I don't see that that should be a problem, since the ECM should get at least as much voltage there, running through 10 feet of 4/0 cable from the battery vs. running through 10 feet of 14 gauge sub battery cable. I've done a cursory check of all the connections, and the other listed causes of this problem (besides loose/dirty connections) is a weak battery. So if the problem persists, I will disconnect and clean terminals and also consider the batteries as a possible culprit. I intend to manage the batteries differently to maintain charge on one for starting, as I have up until now used the same battery on one trip, running a baitwell pump and electronics during engine shutdown periods, then starting on that same battery. Then would alternate batteries for the next trip. I'll be on the water again over the Thanksgiving weekend, and will switch batteries each time I shut down the engine, using the one battery for starting and the other for accessories and electronics. We'll see how that works.

And actually, drifterny, I think it's a great engine, too, and wish they had offered the 175 on my boat, since it's rated for a max 175 hp. But they only offered the 150.

[Harper]

Problem Solved

I was on the water several times over the Thanksgiving Day weekend, and by managing the batteries differently, was able to avoid the problems outlined in this thread. No more starting problems. Previously, I would normally use one battery for the whole day, and use the other battery on the next trip. This time, I always started and ran on battery #2 and when stopped, would run accessories (electronics, bait well, etc) on battery #1. By switching back to #2 to start, I assured that there was adequate voltage to start the motor and not have any voltage drops that would upset the ECM. I don’t care for the way the boat manufacturer set up my dual battery system, so I am going to install a dual battery isolator lead to charge both batteries at once, and a different dual battery switch (a Blue Sea 5511e Dual Circuit Plus) in place of the one the factory used. This will permanently isolate the starting battery from the house battery, and preclude my having to do it manually all the time. From what I’ve discovered in my research in many forums, the sub battery cable and/or low battery power or corrosion on electrical connections is the sole cause of this particular starting problem on the newer large DF series motors. Again, the symptoms are, normal start, rev to a higher than normal start (up to 2000-2200 rpm) hover at that rpm for a second or two, then die.