Yamaha 40hp & Electrics

Glenn collins · 31 May 2010, 20:10

Hi all.

I am hoping someone can point me in a direction with this.

I have been reading around the site in relation to how i "should have" installed my electrics, having had a bit of a worrying moment the other night when out and about, engine stalled and nothing left to get her started again.

I run an SR4 with a battery, cant tell what the amp hour is as its outside and raining so this will be a little hypothetical. The battery is wired to charge of the leads that come out of the engine. Its a Yam 40hp Autolube from a pic of the serial no Bellow hopefully someone may be able to confirm the exact model.

I have from the control box (where key and throttle are) found a permanently live feed and have used this for wiring, through a fuse box my fixed VHF and Single bi directional nav light. The switching panel has a cigarette lighter for plugging in my germin GPS.

I keep reading about the term "Lighting Coil" on outboards and that his is there, as it says on the tin, to power your lights of. Should i have found this if my motor has one and wired the lights and ancillaries of this and kept the battery for starting the engine. By the way, when i turned everything off there was loads of power to start the engine...

As you can guess on not particularly familiar with 12v electrics.

Nos4r2 · 31 May 2010, 22:39

You need an isolator in tthe circuit somewhere.

Personally I wouldn't have done it the way you did, but it shouldn't have killed the engine.

It'll charge through the battery wires. Ignore the term 'lighting coil'-it's a reference to old 2 stroke motorbikes and the type of charging system you have. The 'lighting coil' is part of your battery charging system.

jyasaki · 01 June 2010, 02:03

Are you sure your battery is charging? Put a voltmeter across it, and check voltage with motor off, and with it running. You should have slightly over 12V without running, and somewhere between about 13.6 to 14.8 when running (depending on rpm.) Then, with the motor running, turn on each of the devices you are powering (GPS, VHF, lights, whatever else) one at a time, and make sure you don't get a noticeable drop in voltage. A drop would indicate that something is pulling a *lot* of current.

If that checks out, you may want to check continuity between battery and motor. IF the battery is charging, there should have been no problem cranking the motor.

You can run the electronics and lights and whatever off a fused feed tied directly to the battery (use a distribution block or similar to keep things neat.) Each device/circuit should have its own appropriately sized fuse. In this configuration, you do need to be a bit careful when powering things with motor off to make sure you retain power to start the motor.

Luck;

jky

9D280 · 01 June 2010, 10:38

Does your choke solenoid "click" when you hit the choke switch?

That may indicate that you have a dodgy connection somewhere. I'll try && keep this simple - if you have a duff / dirty connection or a dodgy battery switch, when you apply power to the starter, Ohm's law for resistances in seruies kicks in. This basically says 2 resistors (Motor & dodgy connection) will proportionally share the avaialble voltage" so a chunk of the battery voltage ends up across the switch / diirty connection. Net result is a lethargic or "dead" starter as it will only see 8, 7 or some far lower volts depending on how bad the connection is. (the bigger resistance fgets more of the volts)

The choke doesn't tend to be affected as much in that situation as it has a far higher resistance than the starter. It's only an indication tho'.

Glenn collins · 25 June 2010, 20:54

Having been out on the medway today I think the problem may be different..

Healthy charge with engine off at 12.5v tested the install of the fish finder. At 2/3 throttle making 5 notts on the yam 40. The fish finder was reading 17v ?? I stopped to take a call on the phone for five mins or so and I noticed that during this time all the electics had gone off. And would not give me anything. There seemed to be ample power to start the motor but nothing for the electronics, I had on the VHF and fish finder.

Any ideas or does this look like the regulator is on it's way to the great boat years in the sky.

G

Nos4r2 · 26 June 2010, 06:17

Quote:

Originally Posted by Glenn collins

Having been out on the medway today I think the problem may be different..

Healthy charge with engine off at 12.5v tested the install of the fish finder. At 2/3 throttle making 5 notts on the yam 40. The fish finder was reading 17v ?? I stopped to take a call on the phone for five mins or so and I noticed that during this time all the electics had gone off. And would not give me anything. There seemed to be ample power to start the motor but nothing for the electronics, I had on the VHF and fish finder.

Any ideas or does this look like the regulator is on it's way to the great boat years in the sky.

G

Maybe, or possibly you've got a problem with your main isolator switch too. Voltage will rise quite steeply and possibly cut electronics out if the isolator breaks contact.

I'd change both.

Glenn collins · 26 June 2010, 06:33

Thanks nors.

Anyone have a price on a regulator. Isolator I can get locally

g

9D280 · 29 June 2010, 10:07

Isolator cheaper - change that first, then see what happens.

At risk of having a rant, considering how important electrics are these days, why doesn't someone inventy as marine isolator that is actually waterproof?????

Nos4r2 · 29 June 2010, 13:28

Quote:

Originally Posted by 9D280

Isolator cheaper - change that first, then see what happens.

At risk of having a rant, considering how important electrics are these days, why doesn't someone inventy as marine isolator that is actually waterproof?????

Someone has, but it's for trucks. We use them on fuel tankers. They still don't last more than a couple of years though.