- Mar 6, 2012
- Reaction score
Can give you some Chris.
Hi Jack, to answer your question over compressing would not do this to your rod. I wonder if your cylinder is not slightly out of alignment with your crank. This would cause a ton of stress on the pivot points and that's what you're gettingCheck out the bend in the conrod big-end. I'm obviously doing something wrong. Could over-compressing the engine cause the conrod to bend?
Your Midge is running under-compressed and quite rich-you need to wind the compression screw in further still yet. All these model diesels have a sweet spot of about 1/8" turn (it depends a bit on how fine or coarse the comp screw thread is) for any particular prop load-at which the engine will run smooth without misfiring-less than this optimum and it will run 'rough' as you call it-more than the optimum-and it will start to run 'hard' and laboured. Once you have the comp setting right, then you can play with the needle valve to get it running most economically (ie the setting that it will run longest on)-again-go too far and it will start to misfire and labour to a halt.Hi Gerard,
Thanks for the compliments. Just today I tried to get the other Midge running. It's been sitting on the bench in my workshop waiting for me to find the motivation to try and get it running again. It needs to have the compression screw wound in a long way for it to fire. It will then start and run very roughly. If I back the screw out it stops running.
I also think there may be something wrong with my carb. The engine will run (roughly) with the needle jet removed and my thumb placed over the hole that the jet screws into. I have no idea what that means.
Here's a video of it running. I hope that somebody will be able to diagnose the problem for me.
Hi Chris,Your Midge is running under-compressed and quite rich-you need to wind the compression screw in further still yet.