G Scale Model Train Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter · #1 ·
Hello All,
I have recently acquired an Accucraft Nevada Shortline mogul from a co-worker of mine. Beautiful locomotive that pulls very well on my rugged railroad compared with my much smaller forney. One problem though, it runs like a champ...for about the first 15 minutes. It makes it through the steamup fine, and then it'll run beautifully for about 5 minutes after steamup, but then the fire starts to sputter and eventually it'll go out. But you can hear the gas hissing still, so it's not out of fuel. So I relight it and then it'll run ok for a while but the fire will be trying to go out again. I then relight it a couple more times before it finally runs out of fuel. Wondering if anyone has any insight into why this may be happening? I would also think that with such a large butane tank I'd get more than a steamup from a cold start and only about 10-12 minutes of runtime out of it, or is this normal?
 

·
"Rocky Canyonero"
Joined
·
471 Posts
Here are a couple things I would consider:
Is the filler valve leaking? Do you see frost on the valve or bubbles when wet?

Is the blast pipe loose or modified in any way? Steam in the smoke box could smother the fire. Similarly, excessive water and steam oil could be accumulating in the stack and blocking exhaust flow.

The mogul has very heavy cylinders which require a bit of time in heating to function properly. Even short stops can set back performance creating condensed water to head into the smoke box.

Best of luck
Jeff
 

·
Premium Member
Joined
·
1,101 Posts
You have a cracked superheater right where it splits to the steam chest,happened to a few locos because of expansion and contraction ,the original heater tube is to short to take that stress !Replace with a stainless steel tube or contact Rian !
Manfred
 

·
Premium Member
Joined
·
668 Posts
I think all You need is some warm water in the tender, around the gas tank. the gas after a 15 min run gets cold and turns to a liquid instead of gas. The warm water will keep it gas. Try it (LET US KNOW) You did say that it ran Great for the first 15 Mins. than pupped out and the Fire went out and Gas sputtered, That to Me is frozen gas tank. again Warm water in the Tender. If Superheated Tube was bad or broken You would never get the first 15 min. run
 

·
Premium Member
Joined
·
6,370 Posts
One more thing to try. See if it runs fine with the smokebox door open. Jeff's comment about blocking the airflow may be the problem. These locos need air flow up through the smokebox, so if your superheater tube isn't cracked, then maybe the holes at the bottom of the smokebox are somehow jammed with grunge. It's also possible, (again referencing Jeff) that there is a larger exhaust pipe fitted and that is blocking the stack.
 

·
Super Moderator
Joined
·
411 Posts
The original Nevada Shortline moguls had the gas tank in the cab, later ones in the tender. Can you check which one yours is? If the gas tank is in the cab, the sputter issue can somtetimes be caused by the tank overheating and pressure going too high. Check to see if the gas tank side is touching the side of the boiler in the cab, and to test things, jamb a thick piece of card between the two and see if it makes a difference, if it does, maybe talk to Ryan about a piece of insulating material. If not this, check all the things the chaps above note. If the gas tank is in the tender, later issue models, then it wont be this!

David.
 

·
Registered
Joined
·
237 Posts
I've run across a similar problem with an Accucraft loco where the gas tank filler valve vents prematurely, so it's only partially full. I had to switch out the valve; the good news is that replacements and the wrench to remove/replace them are neither expensive nor difficult to find. In another case, the valve didn't open/close properly and needed some (very) light oil to free up the spring mechanism.
 

·
Super Moderator
Joined
·
4,966 Posts
I'm with Pete and Jeff on this one--it sounds like its an issue with the exhaust and airflow knocking your fire out. Mine acts similarly with my smokebox door closed fully. I can crack it ever-so-slightly and it works much better. I need to do some work on it to open the airflow ports on the bottom of the smokebox so the oil can drain easier. (The thing drinks oil like a fish.)

Good luck!

Later,

K
 

·
Registered
Joined
·
22 Posts
Discussion Starter · #9 ·
Thank you all for your great replies!



To answer a few questions, yes it is a Nevada Shortline Mogul with the tank in the cab. I used the water and dish soap in a spray bottle technique to check all the connections up to the burner and none of them bubbled. However I do often see frosting around the filler valve when I fill it. I have a spare filler valve so I'll get the tool and try replacing that.


I will definitely try running it with the smokebox door open. It seems like its starved for air now that I think about it because it starts to get a blue haze coming out of the stack, and not the same color you see when the steam oil pops and burns off. So I'll try that and I'll also see how gummed up the current damper is in the smoke box. And I'll also check the spacing of the gas tank to the boiler.


If that all doesn't prove to work, then I'll start looking at superheated pipes and jets and things of that sort.


Trevor
 

·
Premium Member
Joined
·
6,370 Posts
I do often see frosting around the filler valve when I fill it. I have a spare filler valve so I'll get the tool and try replacing that.
Some icing is normal when you fill, it cools as the gas enters the tank at lower pressure - sounds like it is working fine.
 

·
Registered
Joined
·
126 Posts
When you say a rugged railroad do you have changes in elevation which requires the fuel to be turned on high? When running well how much pressure is on the Pressure Gauge?
On almost any loco if the gas is turned up real high the fuel will not last that long. from what you described in your first post, you might just be running out of fuel.


Steve
 

·
Registered
Joined
·
22 Posts
Discussion Starter · #12 ·
When you say a rugged railroad do you have changes in elevation which requires the fuel to be turned on high? When running well how much pressure is on the Pressure Gauge?
On almost any loco if the gas is turned up real high the fuel will not last that long. from what you described in your first post, you might just be running out of fuel.


Steve

Yes I do have changes in elevation, however I never have to play with the gas valve. The engine pops off right around 40 PSI. I know its not running out of fuel because when the fire goes out, I can still hear the gas hissing and if I open the smoke box door and stick a lighter in there, it will relight and run for another few minutes until the fire goes out again, and then I relight it again. That goes on until it actually runs out of gas.


Trevor
 

·
Premium Member
Joined
·
2,073 Posts
Trevor, I have the very same locomotive. I found the gas tank in the cab was getting cold so I inserted a piece of copper pipe between the boiler and tank, kept the gas warm but not hot, I don't think that is your problem, and certainly not recommended by the.manufacturer. Have you tried adjusting the air collar, mine is opened to the max?
 

Attachments

·
Registered
Joined
·
22 Posts
Discussion Starter · #14 ·
Hey Guys,


So I did some investigating on the mogul today. It turns out the exhaust pipe was loose. But upon closer inspection, I noticed something. The top of the pipe was crimped!


I took it out and it had been crimped, then a notch cut into it, presumably to make a chuffer or something? Well if definitely didn't work well. So I reversed the crimp and opened the pipe back up again. I then reinstalled it and guess what! Upon first steamup, a volcano of water came out the stack! And boy the cylinders cleared up a lot faster as a result of all this. But she took off and ran the railroad for a good 15 minutes after steamup with no issues. And when the fire finally did sputter, 20 seconds later the fire went out and I cranked the gas valve, no more hiss so it actually ran out of fuel this time!


So it appears the mogul is to a point where it can operate a lot more reliably and fire well! Thank you to everyone who posted on the forum! Still a few more issues to iron out. And that brings up another question?


What pressure is the mogul supposed to pop off at? The pop valve on mine stopped working, so I took my 40 PSI pop valve off my Forney. Wondering if this is the right pressure or whether its supposed to be higher?


Thank you again to everyone!
 

·
Premium Member
Joined
·
2,073 Posts
On mine the top of the exhaust pipe was crimped but it also had a hole in the side. I think Accucraft did that so the hot water/steam wasn't directed straight up, kind of a safety feature. The pop valve on mine lets go at 50, Enjoy the loco now that you have it working better. LiG
 

·
Registered
Joined
·
1,491 Posts
Every Accucraft butane fired loco I have seen has an exhaust tube like that and if you fill the boiler up too much the water injected into the smokebox could douse the flame in the boiler.

I have straight stacks on all of my builds and do have a geyser once in a while. A proper starting boiler level usually prevents that.

That very small hole in the side probably causes some back pressure also, so the conversion you did may have added benefits.
 

·
Premium Member
Joined
·
1,054 Posts
If warm water in the gas tank doesn't work, then remove the gas jet and clean it out by blowing gas through it backwards. DO NOT try and run anything through it as that will enlarge the hole and ruin it.
 
1 - 17 of 17 Posts
Top