Heliproz has a good selection of collets, I would give them a call and see what they say. Glow engines can be a bit challenging to get started in the cold, but it usually comes into effect if it is under 30F. My remote glow igniter makes the meter read low as well if. If you put the igniter on a loose glow plug it should read normal, I have never had a starting problem caused by the inaccurate reading on my OS. To add pix just click upload pics (or files, I forget) and choose what you want.