Roto 35 Two Stroke Petrol Problems
Posted: April 10th, 2010, 1:03 pm
I would be grateful for any advice.....
I've a reasonable amount of petrol experience but most of it on Zenoahs
I bought a decent looking Roto 35 s/h last year. Finally got the model completed and the engine installed. Removed the pump diaphragm to unstick it and cleaned the needles.
My first attempts at running it (without cowl) were very reasonably promising. I got it acceptably tuned (knowing that it would change slightly with the cowl on) and gave it a good half an hour at various throttle settings. I stopped it and easily restarted it about 5 times. I always had the feeling that the tuning could be better - I would give it 7 out of 10 despite my best efforts.
The pump is pulling fuel from the tank back on the c of g without problems.
A week later with the cowl on I couldn't get it to keep running at all. It would generally fire but about three seconds was the longest it would keep going. I tried changing the L needle both ways without success. Went back to the default settings - no better.
Today I removed cowl, squirted carb cleaner through jets and ran it. Much like two weeks ago, reasonably OK but somehow not perfect.
Replaced cowl and I'm back to square one. Fires and a couple of seconds at best. No amount of needle twiddling helps. Back to default settings - no better. Removed cowl - still no better.
I'd be most grateful for any ideas.
Thanks
Chris
I've a reasonable amount of petrol experience but most of it on Zenoahs
I bought a decent looking Roto 35 s/h last year. Finally got the model completed and the engine installed. Removed the pump diaphragm to unstick it and cleaned the needles.
My first attempts at running it (without cowl) were very reasonably promising. I got it acceptably tuned (knowing that it would change slightly with the cowl on) and gave it a good half an hour at various throttle settings. I stopped it and easily restarted it about 5 times. I always had the feeling that the tuning could be better - I would give it 7 out of 10 despite my best efforts.
The pump is pulling fuel from the tank back on the c of g without problems.
A week later with the cowl on I couldn't get it to keep running at all. It would generally fire but about three seconds was the longest it would keep going. I tried changing the L needle both ways without success. Went back to the default settings - no better.
Today I removed cowl, squirted carb cleaner through jets and ran it. Much like two weeks ago, reasonably OK but somehow not perfect.
Replaced cowl and I'm back to square one. Fires and a couple of seconds at best. No amount of needle twiddling helps. Back to default settings - no better. Removed cowl - still no better.
I'd be most grateful for any ideas.
Thanks
Chris