DF 175 2008 Electrical issue

[Werrty]

So i have 2008 175 Suzuki I have had an electrical issue where you can be out all day doing around 25- 30NM and not have an issue then next minute you go to move get up on the plane and when I have the house and starter batteries paralleled the sounder and GPS turn off then with in like 5secs the revs drop. From like 4500 to 3000 then back up and sometimes with full throttle only get 4000 revs. No error codes or anything showing or alarms. So I would stop the motor and shut it down and isolate both batteries. Leave it for a min then fire it up with no issues all day. I then had the Suzuki dealer replace the isolator and wires from the battery to the isolates cause that’s what he thought was the issue.

Took it out for a trip of around 40NM’s no issue.

Went out a week later and had it out had done the normal 30-40 NM and got the boat up On the plane with no Issues then went to trim the motor and soon as I hit the trim switch on the throttle leaver the revs dropped from 4500 down to around the 3000 revs then revs up and down until I dropped the revs right down and shut it down and isolated it. Then did prob another 20NM with no issues.
Any help
Would be great.

[Harper]

Sounds like a bad connection somewhere. Likely ground connection. Going to have to check it really good. I don't know how old your wires are, but check everything. Could be a bad wire, not just a connector. Going to require a very thorough going over of the entire harness.

[redlowrey]

So i have 2008 175 Suzuki I have had an electrical issue where you can be out all day doing around 25- 30NM and not have an issue then next minute you go to move get up on the plane and when I have the house and starter batteries paralleled the sounder and GPS turn off then with in like 5secs the revs drop. From like 4500 to 3000 then back up and sometimes with full throttle only get 4000 revs. No error codes or anything showing or alarms. So I would stop the motor and shut it down and isolate both batteries. Leave it for a min then fire it up with no issues all day. I then had the Suzuki dealer replace the isolator and wires from the battery to the isolates cause that’s what he thought was the issue.

Took it out for a trip of around 40NM’s no issue.

Went out a week later and had it out had done the normal 30-40 NM and got the boat up On the plane with no Issues then went to trim the motor and soon as I hit the trim switch on the throttle leaver the revs dropped from 4500 down to around the 3000 revs then revs up and down until I dropped the revs right down and shut it down and isolated it. Then did prob another 20NM with no issues.
Any help
Would be great.

''''''' This is going to be a simple fix or a hard one, rev's dropping up and down could be from numerous reasons, but when you mentioned the trim switch when you hit it you had problems. I would start at the fuse box check all the fuses mainly the thirty and sixty amp, the sixty amp supplies your trim relay with battery power, and I think also the voltage regulator out put wire goes to the sixty amp fuse and fed back to the main battery cable at the starter.

The thirty amp supply for the ecm relay might be having a voltage drop problem there also, I would be starting at the fuse box.

[Werrty]

Thank you. Are you talking about the fuses and fuse box on the motor? Also I once I had isolated it and it was running fine I then played with the trim with no issues.

[redlowrey]

Yes, I think you have a voltage drop problem not a blown fuse, it could be on the supply side or the ground side. I would run the motor and get someone to trim up and down while you checked the voltages for drop and grounds for voltage on them.

You could have a voltage drop on your main control relay and the output voltage low that would do what you are saying, you need to be electrically savey to be able to check all this.

[Hoosmatroos]

You can pull every fuse and inspect the connections on the fuse and the holder. After that also check all your connectors. Pull the connectors apart and see if any of the contacts are corroded. Clean and push it together.

Like Redlowery said, can be simple or a PITA to find it.

[artdf175]

might check battery post while in the process. clean and tighten
we don’t think about the ground connection as often as the plus side so would take and redo those points as well both at the battery and where they connect to the engine
Art

[pniksnut]

2 batteries on 1 engine is not possible even with an isolator. The new suzukis have 2 regulators for each battery, thats the way to do it. Because you have 2 batteries on 1 regulator in the engine you probably have an voltage issue when the isolator switches from battery or something lake that.

[Harper]

2 batteries on 1 engine is not possible even with an isolator. The new suzukis have 2 regulators for each battery, thats the way to do it. Because you have 2 batteries on 1 regulator in the engine you probably have an voltage issue when the isolator switches from battery or something lake that.

Not sure what you're saying here. Two batteries certainly ARE possible with one outboard, at least in Werrty's case. My DF150 has dual batteries. This has been possible at least since the 2006 models. They are both charged simultaneously by the single outboard through an isolator circuit, and in my setup, one is the house battery, the other the start battery. If needed, the BlueSea battery switch will parallel the batteries to use both to start. Now, if your comment pertains to leaving those batteries in parallel while running, with each battery being charged on a separate circuit from the outboard, I don't know if that would cause problems or not, but I don't think it would. Also don't understand your assertion that new Suzukis have two regulators for EACH battery...?.... Anyway, Werrty hasn't indicated how his batteries are set up.

In any case, if two batteries were wired in parallel, directly connected to the outboard without any isolator, and were both used for the entire electrical system on the boat, including the outboard, that's definitely no problem. It would be the same as having one single higher capacity battery. The attached are pages 11-12 from the 2007 DF150/175 setup manual. It shows the built-in isolator system.

[pniksnut]

didnt know that