llatsni

My Cen .16 MT engine is a little weird... I've run nearly 1/2 a gallon of 10% through it at this stage, but I still spend most of my time trying to tune in the engine (dial it in?). 9 times out of ten it starts as soon as I take it out of its bag and idles ok (I'll get to that later). It runs fine if I gun the throttle and I can tear around for a good while like that, but if I ease it off to about half way and try to slowly accelerate from there it usually cuts. The I spend about 5 mins trying to get it started again. Most of the time it doesnt apear to be flooded, or overheated (its supposed to run a little hotter than norm according to the manual). Just to include: I seem to get a good deal of air in the fuel line is this from the carb? I cant find any leaks (and I sealed the stupid primer on the tank)...

anyway onto the idle... sometimes it idles weird. When I first start it off its quite good, runs for over a min relatively even idle, other times it idles funny, staggered, and other times it idles to fast and the car wants to move by itself. Even other times it idles for a sec and cuts. I do realise that i'm still tuning it, but most of the time theses irregularaties appear without me making any adjustments. I usually adjust to try and fix them!

Sorry for the length... but I really thought that by 1/2 a gallon the engine would be much more smooth and reliable.

If this needs to be moved to the engine section sorry.

Cheers

gubbs3

My Feedback: (1)

Its sounds like the low end may be too lean. A lean low end will let the engine idle for a very long time but that is not the way it should be set. Most well tuned engines will idle for a minute or so quite well but if you hit the gas they will flood out and die. I always set mine so it would idle for about 10 seconds without loading up. A lean low end will also make the idle very erratic and sometimes too high.

A rule of thumb I always like to follow is:

Always make it richer before you lean it out. Its easier to diagnose rich symptoms than lean.

llatsni

Ok, lots of tweaking, reseting, tweaking, etc, etc, etc, and still no real breakthrough with this engine... I realised that if I run it and it does cut, and then I try to start it by priming it, fuel sprays out the joint where the flywheel meets the engine block. Sounds very odd to me, it also feels like some compression is lost?

I'm a little cautious about ripping open the flywheel mechinisim, should I bring it back to the guys in the hobby shop?

Please this is REALLY peeing me off... someone must have a clue?

Thanks

gubbs3

My Feedback: (1)

It sounds like an air leak at the front bearing. Its not complicated to check out. Take all the flywheel and clutch stuff and remove the back plate on the engine. Okay maybe it is complicated. Take off the cylinder head and pull the lower end of the conn rod off the crank so you can slide the piston out of the top. Then you can slide the crank out. On many engines there is a small o-ring on the crank that is recessed into a groove that seals against the bearing. Inspect that carefully and get back to us.