I've got an RCS 140 that I've run several tanks thru it on the bench . I had the engine mounted upright and it ran just fine. Now I've mounted it inside the plane, inverted, and it doesn't want to start as easy, nor idle. I've found that if I keep a little choke on, it will idle , but still has a tendency to want to cut off, and will die immediately if I turn off the choke. I'm running same fuel, and tank. I have installed a tee inline with carb and clunk for filling the tank. I have the same vent as before. I have not adjusted the needles any since it was run on the bench. I'm running large tygon fuel tubing, large tee, and large brass tubing in the tank. I have added a large Sullivan crap trap filter inline also.
My question is do I have a mixture problem? Since this is a walbro carb, which is pumped, shouldn't it remain the same whether it is mounted upright or inverted? And should I have to tweak the needles any? Does it sound like it's too lean on low needle? Any help is appreciated.

PS- newbie on gas engines!

Hey Jai

With the engine slightly choked you are increasing the richness of the mixture, so I would open the low speed needle.

With that said, Inverting the engine should not change the mixture? I would check the fuel lines and your filter to make sure there are no obstruction in them. If you pull the fuel line off of the carb, does the fuel flow easly?


I have been look at this engine and the 180, what plane is yours going in?

http://www.rcshowcase.com/

Doug

Hey stomper,
Thanks for your input. I was thinking it might be a little lean on the low needle, it is also slow to transition to full throttle. I had the engine adjusted before I mounted it in the plane, because I don't have access to the needles. I really didn't expect such a change in the mixture after mounting it. It looks like I'm going to have to drill a hole in the top of the fuselage to reach them. Really didn't want to do that.

My rcs is going in my toplite p40. It's a tight fit, but with the custom muffler from Bisson it worked out allright. I'm hoping to get the bugs out before the weekend so I can test fly it. I really hope I don't have any cooling problems.

It's a little heavy at 11 1/4 lbs. , but most warbirds are! Topflite suggests 8.5 to 10.5 lbs. I've flown the model already with a 1.20 four cycle and it did ok, you just have to really watch it on landings with the crappy robart retracts. The arms bend very easily.

Here's a picture:

another picture

and another...

Oh boy ! I love it . Nice bird, good engine choice, you'll like it when you get adjusted.

I made a hatch to access the mixture screws, I think there is no way around it. What is rhe part number of your muffler ? BTW your plane looks great.

Thanks for the compliments, guys! It's been a long hard road.

I did drill an access hole for the carb needles and made adjustments. Got it right back where it needed to be! I was a little surprised that it would need re-adjusting. I guess maybe the added fueling tee and filter must have restricted the flow some.

foxx -There isn't a part number unless Jim Bisson assigned one to it! It's a one-off. I emailed him pictures and measurements and he worked his magic. He really does a great job. You could probably ask him about this and he'd remember, it hasn't been very long ago.

Here's his email: [email protected]

Wow! It flew like a different plane. That rcs140 really set this warhawk on fire! Now if I could just learn to land it without bending or breaking anything.