md1 wont start

TQA said:
Here is a real last resort trick. It was demonstrated to me an Irish gaffer as we were trying to retrieve a large digger that had got caught out by the tide and spent 6 hours submerged.

We needed to get the engine running and it was almost going but not quite, He removed the air filter, produced his copy of the Sun and removed page 3. He crumpled up three or four pages and poured a little diesel over them. He then put them in the air cleaner and set them on fire. Once the fire was going he put the top back on and told us to give her a go. It started within seconds. The exhaust was ' interesting' for about 20 seconds then settled down.

This merely replicated what the old CAV Thermostart did.

Anyway I offer it as a last resort option.
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I wondered how a thermostart worked. You're snookered though if you don't happen to have a copy of the Sun
 
Kurrawong_Kid said:
I once had an MD2B die on me because the cold start button "extension" got the wrong side of the control lever behind the plate on the back of the engine. Once replaced the correct side the engine ran fine.
Since you freed off the control button during the winter have you inadvertently done this? In effect if the button is the wrong side of the lever it is the same as shutting the engine down with the throttle cable. This would explain why it wont start.
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Good thought - unfortuneately am now away from the boat for a week so can't check this till next weekend.
There is fuel getting to the injector so I'm thinking that the cold start/throttle is ok?

Today I managed to manipulate the fuel lines to the injector such that I could check the injector by holding it into a plastic bottle - there does appear to be a fine mist of fuel being ejected, but no way of telling if it is correct - I'm now suspecting its a compression issue.
Anyway, injector has now been dropped of at the local garage who will send it to Glasgow for servicing.

To further complicate matters - I removed the cover from the valves/rockers and found a piece of metal that appears to have broken off something!
No idea what it is or where it could have come from, and there are no similar pieces in the vicinity - will try and post pics tomorrow.
Extremely odd, but the engine is turning over quite smoothly and there are no knocking or grinding noises
 
gavin400 said:
To further complicate matters - I removed the cover from the valves/rockers and found a piece of metal that appears to have broken off something!
No idea what it is or where it could have come from, and there are no similar pieces in the vicinity - will try and post pics tomorrow.
Extremely odd, but the engine is turning over quite smoothly and there are no knocking or grinding noises
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Eagerly awaiting the pictures.
Last time I found bits of metal amongst the valve gear they were bits of broken valve spring! The valve, the piston and the cylinder head were all a very sorry sight.
 
Could this piece of metal be the valve cap - item 28 in the Volspec diagram for your engine. If it has come adrift somehow the valve timing will be seriously wrong & likely affect starting. There was a thread very recently about a similar problem on a VP 20XX engine when the cap detached itself after the valve clearance locking nuts slackened off.
 
The piece of metal was lying on its edge between the springs.

From the look of it, it has quite clearly broken off from somewhere but where from, and what is it?
 
The radius section does fit nicely over the decompression lever, but I don't ever recall seeing it there and what would it be for - it's not shown in the owners or workshop manuals for that part of the engine
 
gavin400 said:
The radius section does fit nicely over the decompression lever, but I don't ever recall seeing it there and what would it be for - it's not shown in the owners or workshop manuals for that part of the engine
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Cant find a parts diagram of a MD1 ( Dunno where Rosie was looking) but the diag of a MD1B shows it #33 Just called "spring" You have found half of it reckon the rest is in the sump by now!

3912.jpg
 
VicS said:
Cant find a parts diagram of a MD1 ( Dunno where Rosie was looking) but the diag of a MD1B shows it #33 Just called "spring" You have found half of it reckon the rest is in the sump by now!

3912.jpg
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Thats it! - I suppose its an obsolete part and no longer available.

Do you think that is the cause of the non starting?
 
Looking at your photos you'll see that the top of the arm has also been damaged as I described earlier,and the spring as stated has broken, both probably due to wrong clearance of the D/c lever to the arm.
I can't see how a correct clearance can be set accurately with the valve casing off or on, but in operation it does not need a lot to keep the valve open enough to work and decompress. Hope you're able solve this puzzle.


ianat182
 
This is an old engine and most probably a worn out one.It's also a very simple one.By this time I would have it in pieces on my bench.Trying to get worn out machinery to run is a mistake because even if it eventually starts it'll be unreliable at the best of times.I don't know if spares a re still available for this model but it most likely needs a rebore,new rings and piston,valve seats,valves and springs (and that bit,decompressor? that broke off) crankshaft ,maiin and big end bearings checked and maybe new shells,seals,etc.Face it it's an old engine that's given up.
 
gavin400 said:
Thats it! - I suppose its an obsolete part and no longer available.

Do you think that is the cause of the non starting?
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I dont think it will prevent it starting but it might have done if it was lodged somewhere that prevented the valve closing properly. Presumably the decompression lever is secure in the rocker cover without the broken spring ????

The action of the decompressor is adjustable . With the cover on and oil filler plug removed turn the engine until the exhaust valve is closed. Lift the decomprssor lever to vertical, turn the adjuster until it just touches the rocker arm then another 1/2 turn. Lock it in this position with the lock nut.

The instructions are in more detail in the workshop manual ( page 10 in the one I am looking at)

Your photo shows damage to the rocker arm perhaps due to the decompressor having been used to stop the engine!
 
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VicS said:
I dont think it will prevent it starting but it might have done if it was lodged somewhere that prevented the valve closing properly. Presumably the decompression lever is secure in the rocker cover without the broken spring ????

The action of the decompressor is adjustable . With the cover on and oil filler plug removed turn the engine until the exhaust valve is closed. Lift the decomprssor lever to vertical, turn the adjuster until it just touches the rocker arm then another 1/2 turn. Lock it in this position with the lock nut.

The instructions are in more detail in the workshop manual ( page 10 in the one I am looking at)

Your photo shows damage to the rocker arm perhaps due to the decompressor having been used to stop the engine!
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Possibly used to stop the engine under previous ownership - I fully close the throttle and the engine gently stops
 
That's because the throttle lever pushes the control lever(in the crankcase) above the governor to the stop position and the engine is starved of sufficient fuel to run. That's why I think your problem is that the cold start button is the wrong side of the lever and stopping the engine starting. Since freeing the cold start button was the only thing you did during the winter that you havn't checked I think it is the most likely to be causing you the problem./
gavin400 said:
Possibly used to stop the engine under previous ownership - I fully close the throttle and the engine gently stops
Click to expand...
 
Kurrawong_Kid said:
That's because the throttle lever pushes the control lever(in the crankcase) above the governor to the stop position and the engine is starved of sufficient fuel to run. That's why I think your problem is that the cold start button is the wrong side of the lever and stopping the engine starting. Since freeing the cold start button was the only thing you did during the winter that you havn't checked I think it is the most likely to be causing you the problem./
Click to expand...

I will check this on Friday, although there is definately fuel getting to the injector
 
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