Hi everybody.Today I started my converted ST 3000 equiped with Walbro 28 size WA99B (Stihl Chainsaw) ,RCEXL ignition,rimfire spark plug.Oil to Gas ratio 12:1,temperature outside 5 celsius.
With Menz 19X8 7200 rpm,18X10 7450 rpm,canister muffler,about 200cc volume,12mm exhaust diameter.
My questions to you all my friends:
I can hold a steady 1600 rpm idle,but after a prolonged WOT engine stops.If I set idle to 2000 rpm,no more problems.Any Fixes?
After 4 hours of running at various rpm,I inspected inside the engine,it is shiny clean and no traces of anything.VERY oily everything.Can I lower the oil content to about 16:1 ?Oil used is common chain saw type,nothing expensive synth oil.
I did following modifications:On upper side of connecting rod i made 2 more oil holes 1.2mm diameter 30 degrees left and right of existing one,on big end I made 4 holes 1,2mm spaced equally left and right of existing hole.Advance timing is critical:32 degrees.3-4 degrees more or less are very significant in top end rpm gain or loss.
I forgot,the engine is old and used,but still good compression.

When it quits it must be too lean

Everyone runs 16:1 when using gas on these.

Tnx for reply,I must to tell you that I found the sweet spot on L setting and the idle speed I set with butterfly screw only.Quite smokey,does not seem to be lean.Has same performance as DLE 30.DLE 30 also quits if idle is set under aprox.2000 rpm,all this at good L setting.
YO8SSD

Today i made new tests.Here is a video.
http://www.youtube.com/watch?v=mj9D7B1ylms

I run mine at 50:1 ratio with out any problems

Well sir,I understand that,but I still have Bronze bushing in connecting rod.Otherwise the engine is absolutely clean inside and does not overheat excesively.I wish I have your maschining facilities,but we are living in a country where such machines are hard to find.I apreciate your work which inspired me a lot.Please keep going...

The engine sounded pretty good after you set the needle

Post some more videos when you run it more

Another video...

http://www.youtube.com/watch?v=jIK51Bw9xRI

Nice job!

Congratulations Nice Job

I tested Rinfire, SAito AND mine "Rcexl" Spark plugs
Really, not because is my brand but i get 200 rpm more than rimfire and saito spark plugs and a easy starting

http://www.youtube.com/alephterranova#p/u/4/uXlvWZjEr9o

Regards
MAx

I see 3 things I would change. Try a real muffler, put a stack on the carburator, this will stop the blow-by out of the carburator and the engine will be more consistent. Raise the fuel tank to the centerline of the engine. You are trying to draw the fuel up way too far.

Fuel tank level has little to no effect on Walbro or Zama pumped carbs.

AV8TOR