# Aster Jumbo



## zephyra (Jan 2, 2008)

Does anyone here operate an Aster Jumbo with any success. I've been trying to get mine working well but really struggling to get consistent performance. I've re-lined the smoke box, trimmed the wicks, replaced the wicks etc etc but still can't get more than about a lap before it loses power.

The operating sequence is that it comes up he pressure quickly, pulls ferociously for about a lap then quickly loses power and pressure.

One of the the challenges is that the engine has no sight glass which leaves you guessing on water level. It has a very effective axle pump that can quickly overwhelm the boiler and I think this injection of cold water is part of the problem. On the other hand, without the axle pump active, the engine runs out of water very quickly and I don't seem to be able to find that perfect 'cracked open' position for the bypass valve.

Any help gratefully received. Otherwise it is back to the big stuff.....

Robert


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## steamtom1 (Jan 2, 2008)

You mean like this...


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## cocobear (Apr 23, 2012)

Robert, I pm'd you my experiences.


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## thumper (Jan 31, 2009)

Robert, the Jumbo in Tom's video is mine, and I can tell you from experience that it not only pulls well, it is a thirsty devil.

If everything is not working correctly from a plumbing standpoint, it will get low in water and die quickly. Right now, I have to reseat the ball in the check valve, so mine is on the repair bench.

It is essential that you pay attention to the bypass valve exhaust pipe to the tender tank. If there is even the smallest leak, you will run out of water.

Good luck,

Will


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## highpressure (Jan 2, 2008)

* Here's one I scratch built with measurements from Will Lindleys that I took at Diamondhead.*

* 



*


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## dougiel (Jun 3, 2008)

Robert, I have two of these nice loco's.

Novelty was a kit built loco which had not run when I bought it. It had a problem when first tried as the fire kept going out. After help from AsterUK I cut the wick tubes down by 4mm and also the wicks. Extended the meths sump breather by the same 4mm and all was well. Pulls the side of a house down but is twitchy with regards water level. You have to keep a close eye on the chimney. Once you see water or a lot of steam the pump MUST come off.

Hardwicke was a factory built loco purchased unrun from a UK reputable supplier. Unfortunately it showed evidence of being dropped. After a lot of work it runs but I can not get the clack valve to seal. I did the wick mods on this one as well. It shows the same problems as yours. Pressure will rise to 4 Bar in a very short time on the blower, It will run but the pressure will drop to about 2 Bar where it can struggle. I am unsure if the leaking clack valve could cause this. With the bypass closed no water comes back into the tender but it appears no water is going into the boiler either. Usuing the hand pump does seem to work as pressure will drop so water must be going into the boiler.

Dougie L


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## zephyra (Jan 2, 2008)

dougiel said:


> Robert, I have two of these nice loco's.
> 
> Novelty was a kit built loco which had not run when I bought it. It had a problem when first tried as the fire kept going out. After help from AsterUK I cut the wick tubes down by 4mm and also the wicks. Extended the meths sump breather by the same 4mm and all was well. Pulls the side of a house down but is twitchy with regards water level. You have to keep a close eye on the chimney. Once you see water or a lot of steam the pump MUST come off.
> 
> ...


Thanks - I did already extend the breather tube by a couple of mm and cut back the wicks. I didn't think of cutting back the wick tubes but now you mention it, the wicks do seem very close to the boiler. 

Robert


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## dougiel (Jun 3, 2008)

Robert,
did your fire go out while running before you adjusted the wicks and breather tube. If not I would have left things as they were according to the instructions. You must have about 11 to 12 mm of wick length above the wick tubes. Lowering the breather and shortening the wicks will cause less heat in the fire.

If the fire did go out I would suggest cutting four mm of the wick tubes, shorten the wicks by four mm keeping 11 to 12 mm above the tubes, and lowering the breather tube by four mm. This keeps the same amount of wick for the fire while giving more room beteen the flame and the boiler.

Another thing, do not pack the wicks tight !. They need to be quite loose. I was surprised by AsterUK when he showed me how loose. As long as they do not fall out when turned over. They also will swell after the first use so check yours.

Hope this all helps.

Dougie L


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## zephyra (Jan 2, 2008)

dougiel said:


> Robert,
> did your fire go out while running before you adjusted the wicks and breather tube. If not I would have left things as they were according to the instructions. You must have about 11 to 12 mm of wick length above the wick tubes. Lowering the breather and shortening the wicks will cause less heat in the fire.
> 
> If the fire did go out I would suggest cutting four mm of the wick tubes, shorten the wicks by four mm keeping 11 to 12 mm above the tubes, and lowering the breather tube by four mm. This keeps the same amount of wick for the fire while giving more room beteen the flame and the boiler.
> ...


Thanks again - I do have issues with the fire self-extinguishing, so I think I will cut down the tubes as suggested. I always pack my wicks very loosely - it's the one 'magic' trick I always use when helping newcomers who complain that their machines don't create enough steam.

I will let you know how I get on.....

Robert


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## AsterUK (Jan 2, 2008)

Very soon after the Aster Jumbo was launched in 1998, I issued some Tuning Tips which have been added to over the years. A copy can be had by sending me a PM.

Basically Dougie L has covered the key to improved performance which is to reduce the burner wick tube height by 4 mm and the wicks by the same amount. However the breather tube on the fuel tank MUST be extended by at least 4mm to compensate. do this and your Jumbo will do what it should! You can also check out




 AsterUK


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## zephyra (Jan 2, 2008)

AsterUK said:


> Very soon after the Aster Jumbo was launched in 1998, I issued some Tuning Tips which have been added to over the years. A copy can be had by sending me a PM.
> 
> Basically Dougie L has covered the key to improved performance which is to reduce the burner wick tube height by 4 mm and the wicks by the same amount. However the breather tube on the fuel tank MUST be extended by at least 4mm to compensate. do this and your Jumbo will do what it should! You can also check out
> http://youtu.be/GZm03uEJB-0
> AsterUK


PM sent.

I did the modification to the burner tubes yesterday. Was only able to test on rollers but it seemed much better. First run still had the tendency for the fire to extinguish when the regulator was opened but I thinned out the wicks even further and now it seems to be running well. 

Interestingly, I have a second Jumbo (LMS - Black) which I have not fired yet - this one appears to have the burner modification already done.

Robert


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