cnbhome

My Feedback: (2)

I know there have been other threads on this subject, however, I have done everything suggested to no avail. I have a 3W 150 blue cyl engine in a Carden 330 40%. My field is at 5000 ft and the air is very dry 10-25% generally. The condition is that when the plane is inverted, at mid range RPM, it starts to 4-stroke (rich), it will fly in this condition forever, however, it is not generating much power. Immediatly upon rolling upright the engine clears up. I have the elbow installed, standard mufflers, 1 1/2 low and 1 3/4 high needle, the air outlet hole is of standrd size and the moulded carb inlet area has been open and closed. The gas tank is right infront of the wing tube and the lines are straight to the carb. The plane is trimmed to fly in the same attitude upright and inverted. The RPM is only 5500 with a Fuchs 32/10 on the ground. I have the low needle set so that it is hard to start, any leaner and it won't. The transition from slow to fast RPM is good with no stumble. The engine has been back to Gerhard and he says it is ok on the test stand. I am stuck, Help.

Chris

rmh

Reno -- I guess you are still using the old field in the hills?
when you get a condition like you mention --and the tank is reasonably close to being in line with the carb--
(as low in the fuselage as possible -- and the carb is not acting up due to cowl proximity-- then the diaphragm setting MAY need to be tweaked - for more throw -- ask 3W first!!

DMcQuinn

My Feedback: (13)

I have a 3W 100 on a 35% cap232. at half throttle and below, when I roll inverted, the engine slows down noticably and sounds very rich. Makes gurgling sounds. Never quits and begins running strong when the plane is returned to upright flight. I also bought the 90 degree intake manifold and connected the diaphram reference line to the intake manifold. I had also tried to route the reference line into the fuselage.
It seems to me to be too rich, but if I lean out the low end any further, it hesitates upon advancing the throttle.
Ideas appreciated.

captinjohn

Hear is my Idea...get a used chainsaw engine carb off a dead saw and try that. Some dealers have a collection of good used carbs. I believe Sthil has a newer carb that automaticlly leans the mix...even if the air cleaner gets plugged. I am thinking about what could be happening with your engine goig rich, but I cannot come up with a good answer. Maybe RCIGN 1 can. I will do a search to see what I can come up with. Have you tried mounting fuel tank above C.G. ....then when you going inverted it may help the going rich problem?? Good Luck Capt,n

cnbhome

My Feedback: (2)

Some people just like to be the fun of the party, I wish I had the time to reinvent the airplane engine, I just want the one I have to run like it should.

On the 100 I have a 3W 100 in an Aeroworks Edge and it runs perfectly, no conditions at all. It does not have an elbow only a small intake bell that I made. The front of the plane is slotted not completely open and it has a relativly small air exhaust with a gurney lip on it to create a negative pressure zone to extract the air.

On the 150 I have even changed the spring pressure up and down on the in gas needle valve to see what affect that would have but to no avail.

The only thing left to do is to replace the carb.

cnbhome

My Feedback: (2)

Dick... Our field is north of town in Hungery Valley and is at 5000 ft.. I will check with 3W and probably replace the diaphram, it is original and could be the problem.

I plan to fly the plane without the cowl this weekend and see if that changes anything.