🚀 go-pugleaf

 
I am currently having engine problems with a repaired Fox 40. The engine
was crashed in such a way that it destroyed the carburator and
sucked a lot of grit into it. I have replaced the carburator and cleaned
the engine out and installed it in a new plane. The problem is that I can't
get it to run for more than about 2 seconds. If I squirt fuel into the air
intake, the engine will start but does not appear to draw any fuel from the
line and just stops after a couple seconds. The lines are clear since with
everything dry, I can blow into the muffler line and hear air coming out
in the carburator. The following are the possible causes I can decide for it.
 
1. The model is built in such a fashion that the tank is fairly low relative
to the engine. The engine is side mounted with the fuel intake on top and
the intake is level with the top of the tank. Also, the plane is a tail
dragger and that places the tank lower than the engine when on the ground.
I can't get the tank any higher or the engine any lower, do I need a pump?
 
2. The piston and liner got scratched in the crash by the grit and when I
squirt WD40 into the cylinder and turn the prop, I get a little escaping
gas as the piston approaches the top. As I loosing so much compression that
the crankcase suction that is supposed to draw fuel in is failing? How can
I test this and what is the solution?
 
3. I have set the needle valves according to the Fox literature but am
uncertain if they are right. Can someone with a properly adjusted
Fox .40 BB engine measure the amount of exposed thread on both needles
so I can check my setting? also, does the end of you high speed needle
have a bit of metal sticking off of one end or is the end of the needle
flat?
 
4. Is there any parts on the crankshaft directly below the carburator
that help the fuel draw that might have been damaged in the crash?
If so, how do you remove the bearings and crankshaft to check this?
When I cleaned the engine, I could not find a decent way to remove
these parts without major force being applied.
 
Any other ideas? or is it time to buy a new engine?
--
Randy Buckland                               "It's hard to work
North Carolina State University               in a group when you're
randy_buckland@ncsu.edu (919) 515-5491        omnipotent"       -- Q
 
 
time to buy a new engine!