Jeff I understand exactly what you mean. I remember when I was getting my TM built and even the owner encouraged us to run throttle at full speed. Like 3500 rpms! If people on this forum could understand that with heatexhanger technology half of the success has to do with control of truckmount tempature. These days we use 25HP engines to run 45 . 22HP is plenty to run that kind of truckmount. I remember having two White Magic slide in truckmounts. One was a Pro 1500 which had a 24HP Onan engine which ran somewhere around 2500 rpm. The blower ran at 2900. The engineering into the vacuum side of the TM was outstanding. I also had a Pro 1700 which had a Kawasaki 20HP LC engine with a 45 blower which ran at around 3000. Having a coolant preheater heatexhanchanger made the 1700 out perform the 1500 as far as heat but not vacuum. They were both the same.. The 1500 would run with temps around 190 and for us we really liked it. The truckmount ran at ease almost and yet produced outstanding cleaing. The 1700 did equally as well if it were not for a defective Kawasaki engine. Not White Magic's fault. Many of us back in the 1990's did not feel we needed 250 degree heat but rather 190 to 200 was fine and for the technology of the day these machines did pretty well. Other machines would run their engines slower with heatexhangers and there were less problems with them and pumps etc...I think some had the idea that just because and engine is aircooled it must run at full rpms to get adequate cooling but with truckmounts it just doesn't work out that way. I would not be supprised if customers for the less expensive EZ;s Ametex's etc...would have completely different truckmount experiences if they just ran their engines at much lower rpms. True your heat would have been less and your vacuum would have been slightly less but I think there would have been far less problems with these machines. I will take a steady diet of 180 degree heat with less worries of overheating and burning up heatexhangers than running these machines at full tilt and constantly having issues while have superheated soltuions burning up pumps as well. I could be wrong but it may be as simple as this . Running machines within reasonable limits may have prevented a ton of problems related to over heating and vibration! I am not an engineer but I think this is common sense.