Engine bog/elec drain when trimming

[mark1905]

All of a sudden, when I trim up or down.. the engine bogs, the stereo cuts out, and the gauges go funny.

Sounds like a short somewhere..? Where do I look first?

 

[Fishermark]

Re: Engine bog/elec drain when trimming

Sounds like a bad ground to me. Double check all your electrical connections.

 

[mark1905]

Re: Engine bog/elec drain when trimming

Hmm.. I knew something was funny.

Brought it home, checked battery voltage with meter.. 11.3v. Tried to start it.. not enough juice. Starter just clicks.

Brand new cables, all connections good. 2 year old HO DB Electrical alternator.

Sounds like maybe the alternator isn't charging though? Maybe everything was just running off of battery power so engaging the trim motor was enough draw to bog everything?

 

[Fishermark]

Re: Engine bog/elec drain when trimming

That would do it. Go ahead and get your alternator checked.

 

[Don S]

Re: Engine bog/elec drain when trimming

Brought it home, checked battery voltage with meter.. 11.3v.

Try checking that voltage with the engine running at around 1500 rpm? If it's still 11.3, it's not charging. Is the altenator wiring to and from it Ok?

 

[mark1905]

Re: Engine bog/elec drain when trimming

Just checked both voltages.. running @ 1500 and stopped. Both read the same. (After charging for a little to crank the engine.. around 11.7)

I checked the voltage both at the battery and at the alternator post.. both were the same.

Although.. I put the meter between the alternator output post and the black ground case connection on the alternator, and nothing. When the ground lead for the meter was put back on the battery, it went back to 11.7.

Does the alternator need to be grounded to be supplying a charge?

EDIT: When in doubt, check the service manual.. you think? Duh. Very strange that the ground wire on the alternator seems to not be seeing ground..

 

[Don S]

Re: Engine bog/elec drain when trimming

Normally, there is a ground connection on the alternator, check your wiring. Since you installed the new alternator, is it the same, is all the wires hooked up correctly?

 

[cr2k]

Re: Engine bog/elec drain when trimming

If you accidentally sparked or reversed the polarity you would have fried the diodes too.

 

[mark1905]

Re: Engine bog/elec drain when trimming

Yeah.. alternator is over a year old. Everything hooked up the same.

I disconnected the main engine harness, and there was mass corrosion around the power pins. Used some contact cleaner and wire to clean it all off.. reconnected.. and now the wire is reading ground. Charging the battery now, as it's still drained. I'll run more tests tomorrow after the battery is full and report back.

To clarify.. with the engine running above 1500, I should be seeing around 13v at the battery.. correct?

 

[dingdongs]

Re: Engine bog/elec drain when trimming

14.2v whilst running or thereabouts.

 

[mark1905]

Re: Engine bog/elec drain when trimming

Let the battery charge all night.. had 12.7v this morning. Ran it at 1800-2000 rpm, and the voltage at neither the battery or the alternator charging post was different than when the engine was off. Steady 12.7v.

I'm assuming the alternator is therefore bad? Hard to believe being as that I just replaced it 2 years ago, but I do run the hell out of it and it was an aftermarket DB Electrical unit and their products have never been known for longevity in my book. Cheap, yes..


Side question: What is the consensus about replacing the stock 65 amp alternator with a high output 105 amp model?

 

[bruceb58]

Re: Engine bog/elec drain when trimming

yes, or wired incorrrectly.

 

[mark1905]

Re: Engine bog/elec drain when trimming

yes, or wired incorrrectly.

It was working fine for 2 years prior and you would have to be quite inept to mis-wire a 3 wire alternator, although I'm sure it can be done.. lol..

Looks like it's a new one for me.

 

[mark1905]

Re: Engine bog/elec drain when trimming

So yeah.. I start testing the alternator wires, and the purple exciter wire pops off in my hand from inside the black plastic plug on the back of the alternator. I pull the whole alternator off, and I can even hear something shaking around inside the thing.

I called DB Electrical, and sure enough.. I purchased it on Aug 31, 2009. It's barely a month out of warranty. Like I said.. these things are cheap, but you get what you pay for. It seems like I have to replace their cheap-o starter motors once every year and half too. Just.. buyer beware.

Also, I talked to the tech there and swears that no wiring upgrades need to be performed when switching from the stock 65 amp model to the 105 amp replacement. Just drop it in. At least.. that's what he says.

 

[Fishermark]

Re: Engine bog/elec drain when trimming

Also, I talked to the tech there and swears that no wiring upgrades need to be performed when switching from the stock 65 amp model to the 105 amp replacement. Just drop it in. At least.. that's what he says.

You don't need any wiring upgrades, but unless you are running a lot of accessories, you also do not need the amp upgrade. If the price is the same, go for it. If it costs more, I would suggest keeping the extra change for fuel. You will not see any performance gains with a higher amp alternator.

 

[bruceb58]

Re: Engine bog/elec drain when trimming

Hard to say if you need to upgrade your wiring. What gauge wire is on there now?

Basically, if the wire is on the smallish side you will have a voltage drop for a given current. What you will probably find is that with a smaller wire you won't be able to reach your peak 105A because the voltage drop will basically limit the current.

 

[mark1905]

Re: Engine bog/elec drain when trimming

Also a quick follow up on this thread for reference purposes:

After doing even more checking, the main white, square click together harness back by the transom/battery area was totally corroded, and was actually shorting things out when applying power via the trim switch or other accessories. Cleaned all that crap off, and re-did/connected the main power and ground wire connections separately from the harness, and it's all good. Check ALL your wiring regularly.

 

[Fishermark]

Re: Engine bog/elec drain when trimming

Thanks for the update - glad you got it fixed!