BMC 1.5 starting procedure

[ArJayAytch]

OK I know I have to warm the plugs for around 20s by turning the ignition on - but do I need to turn the key that bit further and see the voltmeter drop at the end of the 20s or for all of it? Cheers, Richard.

[Moley]

OK I know I have to warm the plugs for around 20s by turning the ignition on - but do I need to turn the key that bit further and see the voltmeter drop at the end of the 20s or for all of it? Cheers, Richard.

 

Make sure the button on the morse is pulled out to disengage gear (and (from experience) the 'engine stop' is pushed in), then I move the throttle lever to around two-thirds. The ignition key turned to what I would call position 1 does nothing other than turn on the electrics, I tend to hold the ignition key at position 2 (plug heating) for around 20 seconds from cold, (your voltmeter may or may not begin to drop, depending on the state and charge of your starter battery), then key on to position 3 and ours usually fires within 10 seconds.

 

Knock the throttle back to around one third for a minute or so until she's firing smoothly on all pots, then back to tickover.

 

You should only need to go through that pre-heat on the first start of the day.

[Speedwell]

I agree with all that Moley has said except mine did not like that much throttle, no more than about a third, but I expect they are all a bit different. The boat went in for some welding and the engineer said he could not get it started. He had been using full throttle, which he said had been needed by all the BMCs that he had known.

Arthur

[Liam]

I am probably hijacking the thread slightly here but... why do you need to put the revs on to start the engine?

[Chris Pink]

note; glowplugs can be considered consumables and without efficient pre-heating BMCs can be a right pig to start. The clue is lots of grey smoke (good) but no ignition (bad).

[LEO]

Hi,

 

I had a BMC 1.5 lovely little engines but could be a b....r to start, especially on cold days. Half throttle and at least 60 secs on the Glow-plugs plus you need a well charged battery. Started easily then

 

Careful if you take a glow plug out they can break easily (the heater rod) and then it's a head off job to replace it.

 

Hope that helps.

 

Albi

[RobinJ]

OK I know I have to warm the plugs for around 20s by turning the ignition on - but do I need to turn the key that bit further and see the voltmeter drop at the end of the 20s or for all of it? Cheers, Richard.

Some of the Thornycroft engines were fitted with an automatic timer (OK there not real BMC's)!

 

Hopefully you have a glowplug indicator that tells you when you've turned the key far enough, once its warm energise the starter by going all the way.

You can have the engine for for quite a few hours before it gets cold enough to need pre-heating again.

 

The cleaner the engine and heaters, the less you need, starts at about 15s and as it gets a bit sooty rises to about 30s. If it needs longer or is getting difficult you have to think about a decoke or checking the heaters are actually working!

[Bones]

OK I know I have to warm the plugs for around 20s by turning the ignition on - but do I need to turn the key that bit further and see the voltmeter drop at the end of the 20s or for all of it? Cheers, Richard.

 

I never look at my voltmeter, and I have a 1.5 too. Once it has fired up I let go of the key and it goes back to its resting position.

[Speedwell]

I am probably hijacking the thread slightly here but... why do you need to put the revs on to start the engine?

It usually helps but it's not mandatory. My present BMC 1.8 usually starts at idle even after several weeks stopped. My previous 1.5 was not quite so obliging but rarely difficult except after the winter lay up.

Arthur

[chris w]

OK I know I have to warm the plugs for around 20s by turning the ignition on - but do I need to turn the key that bit further and see the voltmeter drop at the end of the 20s or for all of it? Cheers, Richard.

 

Your glow plugs will draw about 40A -50A which will cause a 1 volt drop at least (due to battery internal resistance) even on a fully charged starter battery, (even a 2v drop on a non-fully charged battery) so you will definitely notice it on the voltmeter. It's the way to tell that your glow plugs are actually working (well drawing current at least).

 

Chris

[ArJayAytch]

Thank you all for the info. and opinions. Richard

[onthecut]

OK I know I have to warm the plugs for around 20s by turning the ignition on - but do I need to turn the key that bit further and see the voltmeter drop at the end of the 20s or for all of it? Cheers, Richard.

 

It's a good idea on the 1.5 to periodically take the glow plugs out to prevent them seizing in their bore. While you have them out put them across a battery and make sure they are glowing at the tip ----- I've seen more than one where they are glowing down the stem, which will give a good voltage or current reading but be useless for starting purposes. If the engine is in good order, putting some throttle on is irrelevant, as the pump defaults to full throttle at no revs. Once firing, a diesel in good order should tick over from the off, if required. If the engine is tired, then wind on a little throttle to keep the pace up when it does fire.

 

Mike.