Live steamer running slow???

Shawn

Shawn

Hiking, cross country skiing, snowshoeing
Yesterday and today i took my Accucraft Forney out for some running. While running I noticed it does not run as fast. I have throttle etc. up all the way and the speed is very slow compared to what it was. It chugs along at a perfect speed around the layout but thats at full throttle. It use to take off at full throttle.
-The pressure is fine pop valves goes off at arounf 40 and while running pressure stays at around 30.
- Im not seeing any steam leaks and the temp is perfect for seeing steam.
-the cyliders leak some water at the start but not during running as far as I can see.
-The pop valve will go off throughout the run and burner runs fine.
-The only thing different is the temps are colder outside. Today it was low 40's and sunny. I dont remember it running this slow in the cold weather last year.
Any ideas on what could be the issue or is it just the air temp being cold?
Two possabilities that were mentioned
Something partialy blocking the throttle valve (I took apart and blew it out etc.... will test tomorrow).
the oil being used. (I have been using the accucraft steam oil from day one)
Any other ideas?

My next step will be run it in my garage and see if there is a difference.

A second question how do you know when the timing is off and how do you fix?
 
The symptoms you describe point to the most probable cause being the valve timing has gone out of synch'. I am told US Accucraft locos are prone to this, by a UK Accucraft service agent, due to their design. Something to do with there being no positive system for pinning the whole lot in correct position, unlike a Roundhouse make. I have an Accucraft Mikado, Shay and Mogul and they have all required attention in this area after little use. Very frustrating.

You should also check you are getting full travel on the reverser (is yours R/C ? If so the check the servo is giving full travel to this item) and that is properly connected both sides to the motions. I've had that happen once or twice and it took a while for the penny to drop.

If the loco, as you have stated, is producing steam and keeping up pressure and you have noted no blockages in the steam delivery sytem or leaks then the above is where you should look next. The fault usually manifests itself progressivly but can happen without warning. Have a word with the dealer you bought it from or Cliff at Accucraft's service dept'. It's an easy fix nothing terminal.

I have heard of left over small balls of solder and flux getting jammed in the pipework so hooking up to a compressor might be an idea to blow it out if the valve timing is not an issue.

Max.
 
Almost certainly gonna be timing. Everything else sounds fine. Have you checked in both forward and reverse? Timing of Accucraft UK locomotives is very easy to check.

Lay your locomotive on its side. Locate the regulator reverser piston valve in the centre below the smokebox. It will have a scribed ring around the stainless steel piston rod.
Put the locomotive into reverse gear. As you do this the scribed line will just disappear into its steam chest. If it still shows, or goes in significantly more, then adjust using the locknuts on the shaft ? these may well be loose hence change in performance.
One this is complete, place locomotive starboard side down. Turn the wheels anti clockwise as if running forward. As the main axle cranks reach 6 o clock the scribed lines on the valve rod above the cylinder should just disappear in the steamchest. Adjust if required using the locknuts.

Repeat for starboard side. One of these three adjustments you will probably find have loosened off hence drop in performance.

Your loco is now timed.
 
Thanks guys.
Tag you said "Lay your locomotive on its side. Locate the regulator reverser piston valve in the centre below the smokebox. It will have a scribed ring around the stainless steel piston rod. "
I did this and Im not seeing any scribed line even when I put it in forward or reverse. Is their another way to tell or is the scribed line too far in that I cant see it?
I did put the loco on the side and checked valve rods. The line seemed to where it should be.
If I want to blow the lines with a compresor whats the best way to do this? Is there an adaptor that I need?
In ways Im glad this happened because it gives me a chance to learn how to fix my steamers now.
 
Tag,

Maybe you could show this on a YouTube demo?

:bigsmile:

tagorton said:
Almost certainly gonna be timing. Everything else sounds fine. Have you checked in both forward and reverse? Timing of Accucraft UK locomotives is very easy to check.

Lay your locomotive on its side. Locate the regulator reverser piston valve in the centre below the smokebox. It will have a scribed ring around the stainless steel piston rod.
Put the locomotive into reverse gear. As you do this the scribed line will just disappear into its steam chest. If it still shows, or goes in significantly more, then adjust using the locknuts on the shaft ? these may well be loose hence change in performance.
One this is complete, place locomotive starboard side down. Turn the wheels anti clockwise as if running forward. As the main axle cranks reach 6 o clock the scribed lines on the valve rod above the cylinder should just disappear in the steamchest. Adjust if required using the locknuts.

Repeat for starboard side. One of these three adjustments you will probably find have loosened off hence drop in performance.

Your loco is now timed.
Click to expand...
 
Either that or a chapter in live steam workshop 2. Love that book. With an imminent move to live steam these threads are invaluable.
 
I made a mistake the engine runs at 20psi at full throttle not the 30psi I thought (I read guage wrong) I blew lines out and checked the timing and all seem to be good. I also cleaned the jet and jet line and still doing the same. My next step is to put a new jet in. After that if i still have no luck Im at a lost.

I tried the jet and still no luck. I did find that the reverser piston does have the ring on it and it does go inside farther then it should. I will adjust that and give it a try.
 
Shawn said:
I made a mistake the engine runs at 20psi at full throttle not the 30psi I thought (I read guage wrong) I blew lines out and checked the timing and all seem to be good. I also cleaned the jet and jet line and still doing the same. My next step is to put a new jet in. After that if i still have no luck Im at a lost.

I tried the jet and still no luck. I did find that the reverser piston does have the ring on it and it does go inside farther then it should. I will adjust that and give it a try.
Click to expand...

Bit baffled by this. The pressure in the boiler is nothing to do with how much the regulator is open. The pressure will tend to drop if thrashed of course, but the pressure is dependent on the fire. At what pressure does the safety valve blow??
 
Hi Shawn,
Could be a blockage in the cylinder block, you say the steam lines are clear and presumably the reg is clear, is it possible to connect an air supply direct to the block to see if the wheels rotate? case of elimination.

Shaun.
 
While it must be frustrating to have a fault develop with a previously reliable loco I would strongly recommend you contact the dealer it was bought from or Accucraft's ever helpful service department rather than wind yourself up trying to chase the fault. It's usally the quickest and most relable option. Cost effective too if the loco is still under warrenty.

If the loco is not raising steam or maintaining corect pressure asks the question - is there a leak in the system ? You mention a missing "ring". If its purpose is to seal then it begs the question is this causing the reduced operating pressure ?

Burner problems on Accucraft locos are usually down to poor "broaching" of the jet, a coomon manufacturing fault but that would have been apparent from first use. The only remedy wold be to replace the jet, A blocked jet can be caused by contamination in the gas used or left over debris from the manufacturing process, e.g. flux/corrision, in gas tank or supply system working its way down to the jet. That usually manifests itself in difficulty in lighting up or a tendency for the flame to blow out easily and/or not raise sufficant steam or maintain boiler pressure. One would have to flush out the gas tank, deivery pipes and jet with a solvent (keep away from painted surfaces) and give a gentle heating after flushing and draining in an oven to get rid of any residue before reassembling and re-installing.

All said and done go see the dealer.
Max.
 
Tag the pressure goes up to 40 psi and pop valve blows. It will stay at that until I put throttle up, then it will go down to 20psi. As soon as the throttle is off pressure goes up with no problem. If I turn burner way up it will jump to around 28 when throttle turned on. Some Water does leak from the cylinders and the valve rod. Is that suppose to happen?


Max I did replace the jet and still the same. I will try to give accucraft a call but I really want to learn how to diagnose and then fix on my own. I feel its the only way to learn. I doubt it is left over solder etc..... I have had the engine for a year and it has been run many times since. The missing ring I mentioned was the scribed mark on the piston not a ring to seal. My mistaker.
 
Agreed, the best way to learn is to try to do it yourself, so you know what/how to in future. However, there comes a point where one risks accidental damage which ends up costing to fix rather than a cost free warrenty claim. Especially when one starts taking things to bits. It also can be equaly educational to be able to watch and ask questions as the person doing the "on the spot diagnosis" goes about their business. It works for me, but then I'm a lazy so and so :bigsmile:

If this loss of performance was sudden rather than progressivly over time then it seems to point more to a component failure, an unwitting change in spec of fuel or steam oil (or a replaced component) that does not suit the loco or a foreign body causing a partial blockage in either the steam or gas flow. You see why I'm favouring the service dept' option ?

Max.
 
Shawn said:
It will have a scribed ring around the stainless steel piston rod. "
...I'm not seeing any scribed line even when I put it in forward or reverse.
Click to expand...
Shawn,
The scribed line is very fine, and could be obscured with oil.
You may need to look more closely, and give it a wipe with a fine cloth.
Here's one I prepared earlier:_
5d8bc2fc6bd44674a5a1efe2b19efa94.jpg
 
could your fuel be cold and thus getting less heat into the boiler-
seems simple-but ive had this happen to me and its not always immediately obvious-at least twerent to me
 
Its def not the butane being used in cold weather. I used the same last winter in colder weather with no issues. I also ran it in my garage and still same plus the tank is plenty warm. My next step is to take burner out and clean it. A friend is going to
check the lines for steam leaks with me. I think its going to be one of the two. Im just not seeing the leak, hopefully my friend will be able to.
If anything I did learn to take steamer apart and put back together lol
 
Shawn said:
-The pressure is fine pop valves goes off at arounf 40 and while running pressure stays at around 30.
-The pop valve will go off throughout the run and burner runs fine.
New Haven Neil 2 said:
Sounds more like a partially blocked superheater to me??
Click to expand...
Click to expand...
Doesn't sound like a burner problem.
I'm inclined to go with NHN2 on this one.

But, aren't Accucraft S/V's usually set to blow around 60lb?
In UK anyway.
 
MRail said:
Shawn said:
-The pressure is fine pop valves goes off at arounf 40 and while running pressure stays at around 30.
-The pop valve will go off throughout the run and burner runs fine.
New Haven Neil 2 said:
Sounds more like a partially blocked superheater to me??
Click to expand...
Click to expand...
Doesn't sound like a burner problem.
I'm inclined to go with NHN2 on this one.

But, aren't Accucraft S/V's usually set to blow around 60lb?
In UK anyway.
Click to expand...

I hope its only a blocked line but I did blow the lines out good and still nothing. The reverse valve is off so going to adjust that.
Accucraft is set to blow at 40psi at least their smaller ones. I know people tend to reset them to blow at 60psi.
 
Thanks guys for all the help. After ruling out multiple things we ended up discovering what the main cause is. After taking it apart and putting back together the pressure stayed but the speed was still slow. It was discovered the vlaves were showing signs of wear. Steam was leaking out. It was enough to show the difference in speed. My friend is going to machine new valve pistins? ( think thats what they are called) They will last a lot longer then what Accucraft uses and help improve the engines performance. He had seen this happen to another Forney but much worst. I should have it all fixed by monday. Now I just need to get a lathe etc.... so I can start making my own parts.
 
Shawn said:
Thanks guys for all the help. After ruling out multiple things we ended up discovering what the main cause is. After taking it apart and putting back together the pressure stayed but the speed was still slow. It was discovered the vlaves were showing signs of wear. Steam was leaking out. It was enough to show the difference in speed. My friend is going to machine new valve pistins? ( think thats what they are called) They will last a lot longer then what Accucraft uses and help improve the engines performance. He had seen this happen to another Forney but much worst. I should have it all fixed by monday. Now I just need to get a lathe etc.... so I can start making my own parts.
Click to expand...

Worn out???? What oil were you using in this Shawn? The valves are stainless steel centerless ground running in honed brass bores. Properly oiled with steam oil as per the instructions they should be just about the last thing to wear out of all the moving parts on your locomotive. The only time I have come across 'worn out' valves on Accucraft locos was some years ago when quality control was not the same as today and the valves were, effectively not tight to the bore ? ie effectively worn out from new. If this is the case then I would contact your supplier and ask for a replacement set of steam chests complete with valves. Locally we have Accucraft locomotives that have been running for many years with no sign of wear on the valves. Indeed I have two coal-fired Accucraft locomotives, one five years old and my favourite runner.
 
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