Hello and welcome to Yachting Monthly's How To series, brought to you
in association with GJW Direct. I'm Matthew Sheehan and over the course
of 13 episodes we're going to be dealing withsome of the key issues when it comes to maintenance
and talking to some of the experts to get their tips.
So we've done all our pre departure checks but with the best will in the world
sometimes the engine still won't start. We're going to see there are two main
probable culprits for that. The first is electrical and the second is fuel.
So what we'll do now is look at how we diagnose what the problem is
and how we can possibly get our engine started.
To do that let's go up to our test engine where we can get a better sight of things.
So here's our first scenario:
We've come on, you've switched on your batteries you come to start your engine
and nothing happens.
Now what you need to be able to do is with your multimeter
is quickly diagnose where the problem seems to be. You may be able to fix it,
you may not be able to fix it, but at least you'll be able to narrow down what the problem is.
So we can see we've got some power but it's not necessarily
enough power actually to turn the engine. So just seeing the light and hearing the
noise is not enough. You need to get your multimeter - you need to get to where your
start battery is and you need to test what voltage have you got at your battery.
So we're putting our multimeter onto the DC volt setting,
taking our two probes and we're just checking the voltage of our start battery.
Here we've got 12.45v which is a nicely charged battery so we should have no
worries turning this engine.
So with our systems on now we're just going to check
that we have proper voltage at our starter motor. On this model this is the
solenoid of the start motor which will fire it, so that's where we need to check for power.
Take our multimeter again, one probe on the positive, one probe on your
negative, and we're checking to see do we have voltage and in this instance again
we do have voltage, so we know the power is getting from the batteries to the
start panel and to this starter motor.
Now at any engine problem before you dive into the detail it is always worth
just having a good visual sense check. Is there something out of place?
On this engine we've come around to look at it and as we were checking for voltage
we've seen that this wire is hanging loose. Now you may not know exactly what
that wire does but it's a sleeve connector and there's a spade connector there.
The chances are that that is what's come loose. Now this also happens to be the power
that fires the solenoid and that must be what's stopping this engine starting.
That's it back on.
Now if that hasn't fixed your problem at least now you know
the problem is around at your starter motor. Nothing's turned, nothing's wrong
with the engine so far. We have power to start motor, nothing's turned.
Hopefully putting this wire back on will fix our problem and let's see if it does.
Another problem you can come across is that the engine turns but doesn't fire.
Now that can be a number of problems but whilst we're on the electrical section there is
a problem that you can identify here as well.
Your engine, on its governor, which controls the flow of fuel has a stop solenoid.
If this has failed for any reason that can also be what stopped your engine from running,
as it stops the supply of fuel to the engine. It takes specialist knowledge to know how to
check these but it is worth checking depending on what model you have,
whether it's in it on or off position and that might again
enable you to give technical support some greater guidance.
Another piece of electrical equipment you need
to understand on your boat is the alternator. This converts the power
produced by the engine into electrical charge, which is how you recharge your
batteries as the engine is running. Now you're going to find quite a few wires
coming off the back of your alternator but it's worthwhile just identifying in
advance the heavy-duty positive and negative cables that are attached to it
as this will allow you to conduct a basic check to see whether it's working or not.
We're going to put our multimeter on to DC volts and we're going to put
our two probes onto the positive and negative and we should see
a nice amount of charge coming off it.
Let's start the engine again and see what we get.
Good we're seeing a nice 12.8 volts now which shows we've got a
good charge coming from our alternator.
Well thanks for watching. I hope that was a help. Make sure that you like us, make
sure that you subscribe to us and stay in touch for the next episode.