mike morley Posted October 18, 2021 Share Posted October 18, 2021 I'm trying to sort out a loco that, despite much tweaking, hasn't run right since the day it was built. The controller needs to be wound up far beyond the point needed to get any other loco under way before it even thinks about moving, then suddenly it takes off like a rocket. The controller is promptly wound back to what ought to be the level needed for a steady speed and the loco responds by slowing to a halt. Increase power by the merest fraction and it promptly resumes runaway rocket mode. (Old bikers amongst you: think 1970's two-stroke) My latest investigations have revealed that after just 10 to 15 minutes on the rolling road, with no load (obviously) and the body removed so nothing to retain any heat, the motor was rather more than merely warm. Is this another symptom or the cause of the problem? A quick survey of my loco fleet reveals that, astonishingly, I don't have a single other 1224-powered loco so I've nothing to compare it with, but I was always led to understand that all Mashima motors were cool running. Link to post Share on other sites More sharing options...
Paul H Vigor Posted October 18, 2021 Share Posted October 18, 2021 19 minutes ago, mike morley said: I'm trying to sort out a loco that, despite much tweaking, hasn't run right since the day it was built. The controller needs to be wound up far beyond the point needed to get any other loco under way before it even thinks about moving, then suddenly it takes off like a rocket. The controller is promptly wound back to what ought to be the level needed for a steady speed and the loco responds by slowing to a halt. Increase power by the merest fraction and it promptly resumes runaway rocket mode. (Old bikers amongst you: think 1970's two-stroke) My latest investigations have revealed that after just 10 to 15 minutes on the rolling road, with no load (obviously) and the body removed so nothing to retain any heat, the motor was rather more than merely warm. Is this another symptom or the cause of the problem? A quick survey of my loco fleet reveals that, astonishingly, I don't have a single other 1224-powered loco so I've nothing to compare it with, but I was always led to understand that all Mashima motors were cool running. https://en.wikipedia.org/wiki/Cool_Runnings Link to post Share on other sites More sharing options...
muddys-blues Posted October 18, 2021 Share Posted October 18, 2021 Hello, are you able to take out the motor / gearbox and run them separately from the chassis, to see how it performs running on its own ? what type of loco is it ? Are the wheels or connecting rods free running, with no gearbox or motor attached to the drive ? Good luck with finding the issue Craig 1 Link to post Share on other sites More sharing options...
muddys-blues Posted October 18, 2021 Share Posted October 18, 2021 PS is the model running on DC or DCC ? Craig Link to post Share on other sites More sharing options...
Jeff Smith Posted October 18, 2021 Share Posted October 18, 2021 Sounds like a friction/load problem. Can you undo the grub screw in the gear on the driven axle. Try controlling the motor (lubricate the gears). Check the endfloat of the motor shaft and thus the clearance between worm and worm wheel - it should be just detectable. 1 Link to post Share on other sites More sharing options...
Barclay Posted October 19, 2021 Share Posted October 19, 2021 14 hours ago, mike morley said: I'm trying to sort out a loco that, despite much tweaking, hasn't run right since the day it was built. The controller needs to be wound up far beyond the point needed to get any other loco under way before it even thinks about moving, then suddenly it takes off like a rocket. The controller is promptly wound back to what ought to be the level needed for a steady speed and the loco responds by slowing to a halt. Increase power by the merest fraction and it promptly resumes runaway rocket mode. (Old bikers amongst you: think 1970's two-stroke) My latest investigations have revealed that after just 10 to 15 minutes on the rolling road, with no load (obviously) and the body removed so nothing to retain any heat, the motor was rather more than merely warm. Is this another symptom or the cause of the problem? A quick survey of my loco fleet reveals that, astonishingly, I don't have a single other 1224-powered loco so I've nothing to compare it with, but I was always led to understand that all Mashima motors were cool running. I've never had a problem with the 1224, a lovely motor. I did have a 1024 seize up solid, which I finally identified as rust on the shaft, but it didn't cause these symptoms. This was a few years ago and you yourself gave me the confidence to have it apart and check/adjust the end float, so I assume this isn't the cause? Also assuming the problem isn't caused by a stiff chassis, it sounds a bit like it might be a broken wire to one of the poles - poor starting, lack of control at low speed, somewhat rough running? Whether this would cause heating I don't know but it might be worth checking. 1 1 Link to post Share on other sites More sharing options...
bécasse Posted October 19, 2021 Share Posted October 19, 2021 I had a 1224 which showed just these symptoms. When I replaced it I opened up the can and found that one of the magnet pieces had broken and become loose - that's terminal. 1 1 Link to post Share on other sites More sharing options...
mike morley Posted October 19, 2021 Author Share Posted October 19, 2021 (edited) Thanks for all your responses. To cover all the points raised . . . The loco is a Dean Goods with a Hornby body, a compensated Perseverance chassis under the loco and a compensated Comet chassis under the tender. At one point I replaced the Perseverance chassis with a Comet chassis but it made no difference and I didnt like the Comet chassis so I went back to the Perseverance. During one of the chassis changes it went from Gibson wheels to Markits. It began life with conventional wiper pick-ups on just the loco, had them added to the tender later then changed again to American-style pick-ups. Nothing made any difference. The motor is a rather tight fit in the firebox and at one stage I wondered if the problem was caused by the motor being squeezed. That theory was able to be rejected when removing the body didnt make the slightest difference. At another stage I wondered if drag from the tender was causing the problem. Again, removing the tender made no difference. One thing I have noticed is that the problem is far worse on the track than on the rolling road, to the extent that on more than one occasion I've come to the conclusion that my latest tinkering session had been successful, only to discover that it quite definitely hadnt when I tried the loco on the track. This is the first time I've noticed the motor was getting hot but it might always have being doing that without me noticing before. With regard to end float, I've found with 1220s that "running clearance" is a little tighter than they like and that they prefer just a little room room to move. That's the clearance the 1224 has got and although I dont remember doing so I'm sure I would have experimented with clearances during one of my previous abortive attempts to cure the problem. It's DC powered and after finding another loco of mine, powered by a Mashima 1628, is extremely controller fussy and will only run properly on a beaten up old wreck of a cheap and nasty Gaugemaster I experimented with everything from an ancient H&M Duette to a high-spec Kent Panel Controller via the aforementioned Gaugemaster without, as usual, it making the slightest difference. So much has been tinkered with or replaced without making the slightest difference I'm starting to suspect the problem has to be the motor itself, simply because there's not much else left to try! Barclay's broken wire to one pole will be investigated but the matching symptoms means Becasse's broken magnet is what I'm expecting to find. Thank you all for your assistance. Edited October 19, 2021 by mike morley Link to post Share on other sites More sharing options...
mike morley Posted October 19, 2021 Author Share Posted October 19, 2021 Footnote, prompted by re-reading all your suggestions and realising I'd failed to mention Jeff Smith's. It's fitted with a Perseverance gear bracket and Romford 40:1 gears. When I first built it I was suffering from a plague of gearwheels that werent quite concentric (I had four or five, all from different sources) so mesh, concentricity etc. would have been checked and rechecked very carefully then and the motor run in on the bench connected to just the gears. Link to post Share on other sites More sharing options...
Denbridge Posted October 19, 2021 Share Posted October 19, 2021 14 minutes ago, mike morley said: Footnote, prompted by re-reading all your suggestions and realising I'd failed to mention Jeff Smith's. It's fitted with a Perseverance gear bracket and Romford 40:1 gears. When I first built it I was suffering from a plague of gearwheels that werent quite concentric (I had four or five, all from different sources) so mesh, concentricity etc. would have been checked and rechecked very carefully then and the motor run in on the bench connected to just the gears. Are you certain the gear bracket is true, with no twist? I would think that is the most likely cause of your problems going by your descriptions. I once had one of these in a loco that had been bent up wrong, and the bearings also out of alignment due to the builder opening the holes out too much. I substituted a London Road gear mount & gears, resulting in a total transformation to the owners joy Link to post Share on other sites More sharing options...
Jeff Smith Posted October 19, 2021 Share Posted October 19, 2021 My experience with Mashimas is that if the motor is controllable when unloaded on pure dc (I use a Gaugemaster) then it is a good motor. 1 Link to post Share on other sites More sharing options...
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