Weak performance from Accucraft Mimi or Ruby.

[First Gen]

I purchased my Mimi in 2005 and believe it’s a generation one but produced after the steam chest issue, or that is what AI tells me. I am realizing AI is questionable. I put the Mimi in my garage 3 years ago and fired it up a couple of weeks ago. I am not having fun.

When I put it away it was running better than it ever did and now it’s struggling to pull its tender. Along with the Mimi I purchased ithe RW dual servos and Laser 4 Tx. The Mimi was new and fully assembled. I worked long hours at my job (now retired) so it was a journey laying brass track and converting the Mimi to inside admission and tweaking it good enough to pull 3 AMS ore jennies. So after it’s 3 year hiatus I got it to run but frequently stalls due to low power.

I just received the 2 high temp o-rings to replace the originals and hoping that will fix the problem. It is the 3/4” bore not the more efficient 1/2” upgrade. I spent a few frustrating hours following AI’s instructions on piston removal and luckily didn’t break the cross head. After following it’s instructions and only removing the front lid I asked wouldn’t it be easier to bring the pistons out through the back and the reply was “yes, you can do it that way too”! I took me less than 5 minutes to remove both pistons,

Is there a preferred way to cleaning and what lubricant to use prior to re-installing the new new rings?

Thanks…Rich

 

[dunnyrail]

I purchased my Mimi in 2005 and believe it’s a generation one but produced after the steam chest issue, or that is what AI tells me. I am realizing AI is questionable. I put the Mimi in my garage 3 years ago and fired it up a couple of weeks ago. I am not having fun.

When I put it away it was running better than it ever did and now it’s struggling to pull its tender. Along with the Mimi I purchased ithe RW dual servos and Laser 4 Tx. The Mimi was new and fully assembled. I worked long hours so it was a journey laying brass track and converting the Mimi to inside admission and tweaking it good enough to pull 3 AMS ore jennies. So after it’s 3 year hiatus I got it to run but frequently stalls due to low power.

I just received the 2 high temp o-rings to replace the originals and hoping that will fix the problem. It is the 3” bore not the more efficient 1/2 upgrade. I spent a few frustrating hours following AI’s instructions on piston removal and luckily didn’t break the cross head. After following it’s instructions and only removing the front lid I asked wouldn’t it be easier to bring the pistons out through the back and the reply was “yes, you can do it that way too”! I took me less than 5 minutes to remove both pistons,

Is there a preferred way to cleaning and what lubricant to use prior to re-installing the new new rings?

Thanks…Rich

Hm be interesting to know what a Mimi is, perhaps some pics may help particularly of where you are trying to remove to replace 0 rings.

 

[First Gen]

Hm be interesting to know what a Mimi is, perhaps some pics may help particularly of where you are trying to remove to replace 0 rings.

Hi Dunnyrail, the Accucraft Mimi #11 for the most part is a Ruby but it’s a 2-4-2 with extra gingerbread. The black ring is the over 11 year old original. I need to replace it with the red high heat ring and the entire assembly goes in the steam chest. I don’t know if steam oil is too thick or what the best lubricant would be. AI was telling me to remove the cross head. Even with the 0,035 Allen screw removed it wasn’t going anywhere.

 

[maxi-model]

Accucraft, US, UK, D & AUS market typically use ISO 460 grade steam oil. At least my US & UK locos do. Mimi and Dora's are a bit notorious to get running right. Yes, new seals. I take it the gas burner is running evenly with no spluttering sounds and the boiler is raising and maintaining pressure, around 40 psi. Check for leaks in the gas supply system and that the gas jet is clean with no debris partially blocking. Pop jet in some thinners to clean, no pins in the broaching and blast a bit of gas to blow back clear. Click to enlarge image, Accucraft supplied product but any 460 grade will do.