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Lister hb3 won't start - compression issue?


Ca Jon
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This might take some explaining, so...here goes

I went to start the engine and noticed that though the engine turns over, the starter was not sounding right. Really hard to explain, but it almost sounds like its turning without engaging  and the engine is not starting.

So I took the starter to Graham at Willowbridge marina who serviced it and reported it as working. But the problem remains. My question is what else might make it sound like that? It turns over, but without the oomph, which is why I was thinking about compression. I really dont know, but if anyone has any ideas, they will be gratefully received. 

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What is the start battery voltage while cranking?

 

Have you cleaned the mating surfaces of the battery terminals to bright metal and refitted them? I would use a  smear of Vaseline between the two surfaces if it were mine.

 

If you had lost compression it should spin over faster than normal - with a good battery. I can't see how you can gain compression that would slow the cranking unless water has got into the cylinders.

  • Greenie 1
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Have you got a hand start fitted? There will be three compression strokes for two revolutions of the crank shaft. If you can turn it over any of these (without the decompressors in operation), then you have lost compression. If you can't wind it over any of the three compressions, then you should have enough compression for it to start and run.

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46 minutes ago, Tony Brooks said:

What is the start battery voltage while cranking?

 

Have you cleaned the mating surfaces of the battery terminals to bright metal and refitted them? I would use a  smear of Vaseline between the two surfaces if it were mine.

 

If you had lost compression it should spin over faster than normal - with a good battery. I can't see how you can gain compression that would slow the cranking unless water has got into the cylinders.

Thanks Tony. I’m going to put a heavy duty fully charged battery on and check all connections. 

15 minutes ago, David Mack said:

Have you got a hand start fitted? There will be three compression strokes for two revolutions of the crank shaft. If you can turn it over any of these (without the decompressors in operation), then you have lost compression. If you can't wind it over any of the three compressions, then you should have enough compression for it to start and run.

Hi David, there is a raised hand start, but it’s disconnected. 

5 minutes ago, Tracy D'arth said:

Decompressors off?   Is the starter turning the engine over at all, can you see the pulleys moving?  How long since the engine was started last?

Roof exhaust? Could it have got rainwater down it?

The engine is turning, roof exhaust is covered. I’m wondering if the starter is at fault (it’s making a noise like it’s not fully engaging.). Going to check fuel delivery tomorrow. 

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4 minutes ago, Ca Jon said:

Thanks Tony. I’m going to put a heavy duty fully charged battery on and check all connections. 

Hi David, there is a raised hand start, but it’s disconnected. 

The engine is turning, roof exhaust is covered. I’m wondering if the starter is at fault (it’s making a noise like it’s not fully engaging.). Going to check fuel delivery tomorrow. 

If its not engaging, the engine will not turn. OR if its badly engaged and the engine is turning it will make an horrendous grinding noise leaving you in no doubt that its wrong.

Can you turn the decompressed engine by hand on the flywheel or pulleys with the decompressor in operation?

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6 minutes ago, Ca Jon said:

The engine is turning, roof exhaust is covered. I’m wondering if the starter is at fault (it’s making a noise like it’s not fully engaging.). Going to check fuel delivery tomorrow. 

If the engine is turning then the starter is engaging. Can you judge if it is turning over at the same sort of speed as it did when you last started it successfully?

Could it be that the water pump or alternator has seized and is stopping the engine rotating at normal speed? Try slackening/removing the drive belt(s) and starting again. If it fires this time you know what the problem is. But don't let it run for long without the water pump running.

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11 minutes ago, David Mack said:

If the engine is turning then the starter is engaging. Can you judge if it is turning over at the same sort of speed as it did when you last started it successfully?

Could it be that the water pump or alternator has seized and is stopping the engine rotating at normal speed? Try slackening/removing the drive belt(s) and starting again. If it fires this time you know what the problem is. But don't let it run for long without the water pump running.

Alternator is free and it’s air cooled. 

14 minutes ago, Mike Hurley said:

Starter battery not good enough is my bet, or dodgy connections.

Going to check those tomorrow 

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4 minutes ago, David Mack said:

Was running fine a week ago and turns over on the starter? I would be checking that the decompressors are not holding a valve open, then looking for a fuel problem.

Thanks David. How can I tell if that is happening?

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Best get someone a bit knowledgeable to have a look at the motor................also ...if the starter is a CAV axial .its possible for the internal clutch to slip..........its always handy to have some spare starters you can rob bits out of,because CAV spares are expensive.

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7 hours ago, john.k said:

Best get someone a bit knowledgeable to have a look at the motor................also ...if the starter is a CAV axial .its possible for the internal clutch to slip..........its always handy to have some spare starters you can rob bits out of,because CAV spares are expensive.

Thanks John

i had the starter looked at by a specialist. Might have to go back if all the other things mentioned on this post don’t turn out to be the problem. 

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51 minutes ago, Ca Jon said:

Not sure if this link will work. But here is a video of the starter

 

https://share.icloud.com/photos/025EWVwdCSqS48YLnd4V8PtvA

That sounds like a decompressor is in operation …I’m not sure if they are linked or individual on each cylinder on that engine….looks like they are the same for both cylinders whatever as there seems to be no real compression resistance from that video. Is it the same if you crank it for a bit longer?

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20 minutes ago, roland elsdon said:

Ok glad of that!

can you decompress the engine on all 3 pots and turn it on the belt ( in neutral) and hear the injectors creak?

 

and how is thefuel filter supplied gravity or pump.

I see what you are saying but from the sound on the video there doesnt seem to be any compression for whatever reason...which I would expect even with no fuel. If it was running OK then my money is on an open valve either due to carbon or decompressor.....and it would be unusual for that to happen on all three cylinders....Id expect just a misfire or similar. 

 

I think try turning over by hand by some means even if its the Alternator belt to see if it gets compression at any point would be my next move.

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Cant get video too much of luddite.

really needs to get compression checked.

cant see how you would get no compression on all cylinders , unless the  cam has slipped or broken and he says rockers move.

ours still starts on one even with carbon under seat you start on one and then the carbon gets crushed and flies past your ear.

 

ive even run one for a while with cracked head it just chuffs

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