IAME X30 HW-27A Carb Maintenance


(Colin Jones) #1

I have recently switched from a Rotax Max to an IAME X30 engine, and I was wondering if someone could help me out with the carburettor’s maintenance. The engine currently has 5 hours on it, and from my research at this point the carburettor is due for a rebuild.

I purchased a pop off gauge as well as a full and a half rebuild kit, and when testing (connected the gauge directly to the fuel strainer) the carb popped off at 9psi, and then held steadily at 7psi. From what I’ve seen online, this means that the carb is still in a good condition and does not need a rebuild yet.

This brings me to my question, at which point should I fit in the half rebuild kit, and at which point should I fit in the full rebuild kit? The Tillotson guide mentions the following, however I’m not sure what leaking and sealing exactly refer to.

If it is sealing well, it is necessary to fit a DG kit only; however if it is leaking or not sealing, it is advised to fit an RK kit.

There are also some other things that I am unsure of:

  • Is there any reason why I should test the pop-off pressure with the carburettor dismantled using the adapter, as opposed to testing by just connecting the pop-off gauge to the fuel strainer?
  • Should I replace the spring at some point, or should I change it only to alter the pop-off pressure? With regards to the latter, from what I’ve read changing the pop-off pressure seems to richen or lean the carburation throughout both the low and high jet. If so, what is the point of altering the pop-off when you can achieve the same thing by tuning both jets?
  • Apart from the things I mentioned, is there anything else to keep in mind to keep the carb performing optimally?

Thanks in advance for any help!


(Tony Zambos) #2

Pop-off pressure is not the only determining factor in rebuilding a carb. The amount of usage or the length of time between carb rebuilds will have more influence. If the carb does not hold pressure, could be a sign of a worn or damaged needle and seat. With time and usage, the pump diaphragm loses some of its elasticity. We have a short racing season, so I will replace the needle and seat once a year. As for the diaphragm, after every couple of race weekends works.


(Colin Jones) #3

Thanks for your reply! I will open up the carb this weekend and have a look at the state of the diaphragm. If it looks worn, I’ll fit in the half repair kit.


(Tony Zambos) #4

If you are not aware of your carbs history, may just want to install the gasket set to have a base line on the carb. There are several videos online on rebuilding the carb. Of coarse, I couldn’t find the video I wanted, but these will give you a start. Good luck.