Accucraft Mortimer not steaming correctly

W

Winsley

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As a newcomer to live steam, I have just one engine, a second hand Accucraft Mortimer. It used to run beautifully until it had a derailment at speed, on a curve, and rolled over 360 degrees.
It appeared to have no damage, however.......
Since the accident, when I start the loco, the gas burns well, the pressure builds correctly, but as soon as I open the regulator the fire goes out. I'm guessing steam is leaking into the gas jet somehow.
Anyone else had this problem and can suggest where to start to look for the fault?
 
That sounds a bit odd. Have you checked that there isn't a blockage in the flue, or the blower pipe?

The flame could go out if steam were directed back towards the burner, but there is usually plenty of space for it to escape from the smoke-box. Try again with the smoke-box door open, if there is nothing obvious,

Another possibility is a cracked super-heater tube, that would allow steam close to the burner.

I'd like to know what you find.
 
have you got a blocked jet?
take off the jet cone and give it a squirt throught with your gas nossle on the can you use to fill, it may be dirt which is in the cone and got dislodged when the engine rolled. is there any old pt tape or perished tape round the banjo or jet? are your o rings in good condition?
 
When I leave my accucraft loco for a long time between use, it find sometimes the gas control is a bit temperamental, if you unscrew the gas control valve and apply a very small amount of steam oil to the thread and then replace it can help a a lot.

Obviously make sure the tank is empty when you do this!

Dan
 
Triple posted.
 
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a98087 said:
When I leave my accucraft loco for a long time between use, it find sometimes the gas control is a bit temperamental, if you unscrew the gas control valve and apply a very small amount of steam oil to the thread and then replace it can help a a lot.

Obviously make sure the tank is empty when you do this!

Dan
Click to expand...

I find Vaseline better than steam oil for the gas valve. It seems to stay put longer than steam oil.

Winsley's problem seems to be 'flame out' as soon as the regulator is opened, so I don't think it will be dirt in the jet. Having said that, no problem with giving a blast through to make sure.
 
Triple posted
 
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Hi

Does your gas burner have the adjustable ring that can move back and forth over the air inlet holes???

Accucraft started to supply this a few years back, It sits over the air inlets and held by a single thread.

If so it is just possible that this shifted in your "roll over" accident and needs readjusting! Loosen the screw and gently slide back and forth to optimise the burner!

If you don't have one, it's probably the other solutions suggested above. Though Accucraft used to supply the ring as an FOC after sales fix for troublesome burners.

Also I had a similar problem with a direct water leak from the back of the steam regulator, which dripped straight onto the burner inlet, if that's the problem, it would be visually obvious!
 
Thanks very much for the suggestions.
I've cleaned out the gas jet - perhaps it helped because the loco lit on the first match, first time ever!
In looking through the loco, I noticed that the the chuff pipe was hanging by only a thread so I've tightened this up.
The result of this is that the loco fired up perfectly this evening, into forward gear, and with a bit of pushing and nudging of the wheels whilst it was up on two blocks of wood, it would go fowards without putting out the flame.
When in reverse, lots of hissing and steam from the front end of the engine, but the wheels would not turn at all. Leaving the regulator open for too long in reverse puts out the flame....
Also, should my super-heater tube glow red just beneath the gas jet?
 
It certainly will if the regulator is shut, they are made of stainless steel so can stand a little of that.

It sounds as though the sudden stop may have dislodged something in the valve timing. It certainly bears checking.
 
As far as the original problem of derailing is concerned, a lot of people will tell you that suspension is not required on these 32mm and 45mm locomotives.

However, my experience is that full suspension - and if possible, a correctly loaded leading truck or bogie - makes for much more stable running and a big increase in possible cornering speeds.

On locos without these features I would be very cautious on cornering, especially with a wheel base as short as the Mortimers.
 
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