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Beta glowplug wiring


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Like most Beta engines, my Beta 43 usually starts quite easily without recourse to using the heater plugs. However it has always seemed a bit reluctant when it has been left for a long time (say a week or more) and using the heaters seemed to make very little difference, so I started looking for any possible problems. One particular point I found was that the voltage on the heater plugs was only about 8.5 volts, even though the starter battery was good.

I spoke to Beta technical support but they barely listened to me, merely emphasised that their wiring loom had been designed by professionals and that there couldn't be a problem unless the connectors were dirty. Well the connectors were OK, but I have the extended loom which is 5m long, so the current for the plugs has to pass through more than 11m of cable as well as the fuse, the switch, and 2 connectors before reaching the plugs. Now the plugs are nominally 1 ohm each so could ideally be expected to take 48 amps (or presumably less as they heat up?), but the cable that Beta have used is only 2.5mm which not only is seriously under-rated for this current but also provides a significant voltage drop. It's probably a good thing that the cable limits the current however, as everything passes through a 40A blade fuse too.

Anyway, despite Beta's advice that it was a waste of time and would have no effect, this week I fitted a relay to the circuit so that  the plugs now get almost 12v. Result, after a month standing, and on a bitterly cold day, the engine fired up instantly after its 10 seconds of heating. SO if you have similar problems, look at the voltage on the plugs and consider fitting a relay.

Incidentally I added one small refinement, that I can now select whether the heaters are powered by the starter or the domestic batteries, which will allow me a better chance of starting if I am suffering from flat batteries.

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37 minutes ago, Keeping Up said:

... However it has always seemed a bit reluctant when it has been left for a long time (say a week or more) ...

I see this on my Beta 43 too. Does anybody know what would cause this? Why should leaving it for a few weeks make a difference compared with leaving it for a day or two?

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11 minutes ago, system 4-50 said:

I see this on my Beta 43 too. Does anybody know what would cause this? Why should leaving it for a few weeks make a difference compared with leaving it for a day or two?

I can only assume that it's a combination of the block and pistons taking more than one night to become really really cold, plus possibly then a bit of dampness or condensation forming inside the Cylinders as the temperature constantly cycles day by day.  At first I thought it was compounded by the fuel draining away, possibly flowing backwards through the lift pump, but then ruled that out by the fact that it still happened if it was left with the tank filled to the brim so the fuel was above the highest point of the engine.

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Our Beta 43 has 3000 hrs so I suppose it’s relatively new, but it always starts nearly instantly even in cold weather and I stopped bothering with the heaters a few years ago.

it seems to me that if leaving it for a few days, as opposed to one day, makes a difference then something changes during that time. Perhaps it is a fuel issue - we had a manual pump (on top of the filter) that sucked a tiny bit of air in over a period. But then you say that it happens despite your fuel tank level being above the engine (ours is well below). So perhaps it’s a reduction of compression due to bore oil making its way back to the sump, less compression = poorer compression ignition, but that can be compensated for by the heaters - when they are working properly.

When next on the boat, I’ll have a look at the heater voltage out of interest.  We have a reasonably beefy bus bar linking the heaters, but the supply cable does look fairly weedy.

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9 hours ago, nicknorman said:

Our Beta 43 has 3000 hrs so I suppose it’s relatively new, but it always starts nearly instantly even in cold weather and I stopped bothering with the heaters a few years ago.

it seems to me that if leaving it for a few days, as opposed to one day, makes a difference then something changes during that time. Perhaps it is a fuel issue

This is my experience too, I have only used the glowplugs once in 3 winters, and that was to see what difference they made (next to none).

Unless the engine is pretty worn, it seems to me to be more likely that fuel has somehow drained back to the tank.

Have you tried pressing the rubber plunger on the top of the oil filter a few times before trying to do a cold start?

Edited by cuthound
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Most installations there will be a stop valve on the fuel delivery line somewhere near the tank. Try closing that if leaving the engine off for a few days, then open it again just before trying to start. This should show if it is the fuel draining back to the tank or not.

I've also got a Beta 43. Ten years old and around 3k hours. As others, no problem starting whatever the weather. Using glow plugs will save a couple of seconds cranking, but can start without them down to minus silly temperatures when the canal is so frozen the boat isn't going anywhere.

On the wire length to the glow plugs, my understanding is that the earth return is via the engine block, so the length of 2.5mm2 cable is only from the Beta panel to the engine, not panel to engine and back. The return path is via the same path that the earthing for the starter motor takes. Worth checking the big plug and socket for corrosion on the connections as this can put a high resistance in the circuit and severely limit the voltage and current that the plugs see. Similarly with the earth lead back to the battery, but if the starter is spinning nicely then this is less likely.

Jen

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As a complete lay man with engines, I have to wonder why heaters actually exist if the consensus is that they shouldn’t be needed, even in winter, unless something is wrong?

Surely the fact that they exist means that something quite normal happens to require their use?

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4 minutes ago, Richard10002 said:

As a complete lay man with engines, I have to wonder why heaters actually exist if the consensus is that they shouldn’t be needed, even in winter, unless something is wrong?

Surely the fact that they exist means that something quite normal happens to require their use?

In my experience the Beta 43 is the exception in not requiring the glow plugs to be used to assist cold starting.

Certainly the Mitsubishi 1.4 and BMC 1.8 in our previous boats wouldn't start without the glow plugs being used in really cold weather.

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My engine has done about 3000 hours

Last month it had been left for 5 weeks and it was extremely difficult to start. The fuel tank had been topped up before we left the boat, so the fuel was at least a foot above the top of the engine. So it couldn't be draining back into the tank. Pumping the primer a lot felt as if there was fuel there and didn't help. When the engine did finally start, there was a big cloud of black smoke (not blue or white) which seems to suggest that there was no lack of fuel.

The negative return is indeed via the block.  But the positive supply travels from the engine up the harness to the dashboard to the switch and back to the engine, so 10m plus about 1m around the engine first

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5 minutes ago, cuthound said:

In my experience the Beta 43 is the exception in not requiring the glow plugs to be used to assist cold starting.

Certainly the Mitsubishi 1.4 and BMC 1.8 in our previous boats wouldn't start without the glow plugs being used in really cold weather.

How true. I have owned two boats with beta 43 jobbies in and both always started instantly. I at present have an Isuzu which again is awesome but will not start even in summer without heaters, its no big deal as that's why they fit heaters but why is this? Mechanical bod please inform as I though they were of a similar design engine. The only boat engine I have owned that started quicker was a Bukh that started by just looking at the key instantly whatever the weather.

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6 minutes ago, mrsmelly said:

The only boat engine I have owned that started quicker was a Bukh that started by just looking at the key instantly whatever the weather.

Does the Bukh stop when you look away from the key then?

If so progress along the cut must be difficult. :giggles:

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15 minutes ago, Keeping Up said:

My engine has done about 3000 hours

Last month it had been left for 5 weeks and it was extremely difficult to start. The fuel tank had been topped up before we left the boat, so the fuel was at least a foot above the top of the engine. So it couldn't be draining back into the tank. Pumping the primer a lot felt as if there was fuel there and didn't help. When the engine did finally start, there was a big cloud of black smoke (not blue or white) which seems to suggest that there was no lack of fuel.

 

Stumped. A weird one and not typical of the Beta 43 as you've gathered.

The obvious solution is to go boating more often!

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48 minutes ago, Jen-in-Wellies said:

Most installations there will be a stop valve on the fuel delivery line somewhere near the tank. Try closing that if leaving the engine off for a few days, then open it again just before trying to start. This should show if it is the fuel draining back to the tank or not.

I always close this when leaving the boat so its not this. The engine is on 1300 hours. As for more boating, if only the family would permit it!

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Another Beta 43 user here.

4500 hours on the engine. It too fires up straight away without using the glowplugs.

The OP mentions a 40 amp blade fuse. Is this the one that lurks behind the gearbox oil cooler, dangling on a couple of wires?

Strikes me as not the best place to hide put a fuse!

 

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My Beta never needed the plugs in its first year or so. Perhaps the situation is:

Beta wiring makes the plugs ineffective.

Beta's don't normally need the plugs so it doesn't normally  matter.

I have an issue which can make it difficult to start after a week or two. So does System4-50, it may be the same issue or a different one.

The issue can alleviated by using the heater plugs, but only if they are working properly.

More boating is the best solution.

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4 hours ago, cuthound said:

Have you tried pressing the rubber plunger on the top of the oil filter a few times before trying to do a cold start?

<pedant mode> I think you mean the fuel filter? <\pedant>

:giggles:

Not often we catch you out, ch :D.

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1 minute ago, BruceinSanity said:

<pedant mode> I think you mean the fuel filter? <\pedant>

:giggles:

Not often we catch you out, ch :D.

Yep I meant fuel filter. I blame a combination of my phat phingers and autocorrect. Together they come up with frequent gibberish and rarely a real word in the wrong context. :blush:

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2 hours ago, mrsmelly said:

who the hell are these so called Boaters who don't start their engines for over a week? Masses of solar power? Do you push the boat everywhere? seems weird to me.

The power of one solar mass would keep a engine going for over a week...

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8 hours ago, cuthound said:

In my experience the Beta 43 is the exception in not requiring the glow plugs to be used to assist cold starting.

Certainly the Mitsubishi 1.4 and BMC 1.8 in our previous boats wouldn't start without the glow plugs being used in really cold weather.

Neither would my Vetus M3-10. Absolutely no chance without the heaters. 

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