STARTING ENGINE

DAVEYB24 · Posted: Sat Jun 05, 2010 9:32 pm Post subject: STARTING ENGINE

I have twin Yamaha 40's on a 22'. The starboard engine starts fine. the port engine is more difficult to start. When I engage the key to start on the port engine, i get one turn on the starter and then nothing. I then bring the key back to "off" and try and again, and then the engine will then turn over and usually start. The one interesting thing is that the instrument gauge for that engine will cut out until the engine starts. It will show the RPM and hours on the engine. the startboard engine instrument panel (guage) does not cut out. I;m not an electrician, but think it is an electrical problem. any body have any ideas? thanks

BrentB · Posted: Sat Jun 05, 2010 9:45 pm Post subject:

I would begin by checking the electrical connections at the battery. It maybe a loose connection, some corrosion or bad terminal.
Remove wires, lightly sandpaper connections, clean, add electrical protector and discard wing nuts and use washers and hex nut

DoryLvr · Posted: Sat Jun 05, 2010 9:56 pm Post subject:

I had this issue on my last boat. You may have a loose connection on the battery...which in turn has caused an issue with the starter. You may need to replace the starter and also tighten the battery connection. The loose connection arcs and causes a power surge to the starter. They were nice enough to replace my starter under warranty. It was a Yamaha too.

thataway · Posted: Sun Jun 06, 2010 5:32 pm Post subject:

I would pull all of the battery connections (both engines) and wire brush them, clean them, and re-assemble, with a corrosion block material. Same for any fused connections you ca find. It is often in the ground circuit.

drjohn71a · Posted: Wed Jun 09, 2010 6:05 pm Post subject:

If the gauges are cutting out on the start, you most likely have some battery or connection problems like Dr. Bob says.

I had a 12V outlet put in each of my battery circuits so I can plug in one of those battery dial readout things and that has helped me to understand how a battery can seem to have power, but not actually be able to deliver the full load.

Also, I don't know how or why it happens, but sometimes the in line fuses on mine will partially 'blow', i.e., a slightly darkened area on the fuse link, but not enough to totally shut down the system. If in doubt, clean and tighten all connections and replace any old or questionable fuses.

John

BrentB · Posted: Wed Jun 09, 2010 9:01 pm Post subject:

What is the fuse rating?
Are the fuses loose in the holder?

drjohn71a · Posted: Thu Jun 10, 2010 9:57 am Post subject:

The fuses on the TomCat's charger are 5 amp for the two starting batteries and 10 amp for the house batteries. Also, there are the fuses wired directly to the battery cables just off the terminals for bilge pumps and some other devices.

In my case, the red 10 amp fuses have partially "blowed" with a dark area on the fuse connector metal, but not enough damage for it to separate.

The 10 amp on the house batteries will blow if your house batteries are low and you plug in a spotlight or enough accessories to draw over 10 amp. The charger fuses will blow if you draw more than 5 amp over a low starting battery and more than 10 amps on the house battery.

The charger that comes with the TomCat is plenty capable to my thoughts BUT it seems to tend to boil the water out of the batteries. For very long term storage, I use those little 450 milliamp float chargers from Harbor Freight on all my farm trucks, tractors, mowers, etc.. The boat I use all year long, so it gets the higher amp charge.

I know there are ppl here who tout the need for a faster, higher amp charger, but the 5,5, and 10 amps are high enough to boil the water out.

Anyway, I have had problems with the batteries running low on water, then losing their potency and then the charger fuse blows or partially blows when you draw 10 amps or more.

Additionally, I have found that the partially blown fuses get really really hot and think they could become a fire hazard if left for long.

John

BrentB · Posted: Thu Jun 10, 2010 11:29 am Post subject:

Thanks, John

I thought the fuse was not seated fully or a gap in the fuse connector and arcing was occurring

mjsiega · Posted: Thu Jun 10, 2010 7:56 pm Post subject:

John,

Why does the 10 amp fuse blow only when the house batteries are low and you plug in more accessories? I would imagine that if they are low, they're not going to have the voltage to deliver the the amperage all the accessories are trying to pull.

-Mark

journey on · Posted: Thu Jun 10, 2010 11:07 pm Post subject:

Mark,

The accessories run with power, not voltage. Since power = voltage X current, as the voltage goes down, the accessories draw more current. As the current goes up, da fuse blows.

Boris

Rwinemaker · Posted: Fri Jun 11, 2010 7:29 am Post subject: Starting Engiine

Boris,

I think your explanation is off. Using E=IR, current or I=E/R then if E goes down current will also go down. Using the power formula P=IE, if the voltage goes down the power in watts also go down. I've seen something similar on my boat but I'm running twin Hondas. The last time I had the problem I tried to turn over the problem port engine when I got home and it turned over fine. I'm interested in hearing what causes the issue too.

Russ

edwardf · Posted: Fri Jun 11, 2010 8:35 pm Post subject:

Guys,

So here's something to ponder. Put a wrench across the terminals of your starting battery as in a dead short. What would the terminal voltage E be then? E would go down to zero wouldn't it? What would the current, I, be at that moment? Zero right?

It be OK to do this because as E goes to zero I would go to zero, right?? I mean according to ohms law.

Ed.

journey on · Posted: Fri Jun 11, 2010 9:11 pm Post subject:

OK, Russ,

What you say is true for a pure resistive load. Such as a wire wound heater. However, look at an electronic device. They regulate the voltage down to some level required by their electronics. As the input voltage drops, the electronics wants a constant power level, and the regulator will use more input current.

And as voltage drops on a DC motor, the speed will drop and the current increases. Remember a DC motor balances load torque and back EMF. So as it slows down, the back EMF decreases and the current increases to drive the load (I hope.) That's why DC motors are such good servo motors. They generate maximum torque at stall, and use a lot of power doing it.

So if you turn on "accessories" and a fuse blows (current gets too high,) I'll bet those accessories use constant power.

As for the battery, the current will increase until the internal battery resistance balances the battery voltage. E=IR. I used to take my brothers dry cells and short them with wire and watch the wire melt. Never grew up.

As for the Honda, I only solve starting problems for 2-strokes.

Boris

Byrdman · Posted: Fri Jun 11, 2010 9:55 pm Post subject:

Loose ground more than likely.
A large portion of issues get back to the ground, or lack there of.
This, of course, can change from the time we load our boats and drive cross town/state/country.....as, what is tight will become loose, and what should remain loose...well...it just get tight.

Hate it when that happens.

Byrdman

drjohn71a · Posted: Sat Jun 12, 2010 10:01 am Post subject:

I offered my experience on this odd occurrence , 10 amp charger fuse blowing when a 12 amp spotlight is turned on over dead battery, because I have been fighting electrical problems for quite a while on the house and Port engine circuits.

The start of the problems new seems to have been that, when new, I first installed those battery filler tubing sets over the aft Port two batteries, assuming that they would be on the same circuit since they are next to one another.

The symptoms I was having was a low or dead Port starting battery and weak house batteries, even after long charging at the slip. Of course, using the jump connector switch let everything work OK.

It now seems that, when I flooded the water filler tubing, it had connected the Port engine battery with one of the House batteries (one is adjacent to the Port battery and the other House battery is under the dinette cabinet) it was shorting out the two circuits causing a brief overload and partially blowing the 10amp fuse on the battery.

I would come back to the boat, connect the jump, the batteries would charge while cruising, and all was OK for awhile, but the system did not work well or hold a charge well.

While at the slip, I would notice that the 10 amp House charger fuse kept blowing and it was not until I plugged in a spotlight, while charging, that I saw that, evidently, when the battery is dead and you draw over 10 amps on the circuit, it blows the fuse. Dr. Bob and all you electronics experts are welcome to wade in here, but this realization is what finally led to my solving the problem.

So, I put separate water filling tube sets on each battery, put a 12V socket on each battery's circuit so I could read out what was happening on each leg separately, and replaced ALL of the fuses when I figured out that some had "partially" blown. Perhaps it was that a brief connection between the battery systems with the filler tubes was partially blowing the fuses.

At any rate, I know for certain that, if you put a heavy draw on a dead battery while it is being charged, that exceeds the amperage of the charger, you will blow a charger fuse. I was buying 10 and 5 amp fuses by the dozen trying to figure this out.

btw, my first hint of troubles should have been when I notice the Port bilge pump was not working. I had thought that the pump had probably frozen over the winter. Now I see that the problem with the pump was that the Port engine battery was shorting out on the House battery circuit.

John