Sparks coming from my 2343 F3 engine

Clean your wheels and pick up rollers and spray electric contact cleaner on the pins on the rollers and clean your pullmor motor up with the contact cleaner and brushes and bend your brush springs down and oil bushing bearing on top brush plate and check bearing in brush plate if its worn replace brush plate and check your armature with ohms meter at the three copper sections to center shaft ground. If you get a reading the motor is shorting out and also make sure your armature has 0.30 end play. There is adjustment screw on top of brush plate. Also check all your wires if in good shape no bare places etc. 

Sparking is caused by bad electrical contact between the wheels, pick-up rollers and the track.

Cleaning and lubricating the motor, and oiling the axle bearings will result in a smoother running locomotive that will use less power.

Use hardware store naphtha to clean everything.

Larry

Most of the F-3s have horizontal motors.  I have a 2333, 2343, and 2353 and all have horizontal shaft motors.  Poor lubrication will cause the motor to draw excessive current and cause sparks.  Barring that, clean the wheels and track.  A little sparking by the pick-up rollers is normal.  

To properly oil an F-3, you are going to have to disassemble the power trucks.  There are bearings and gears inside the gearbox that carries the wheels.  Use ordinary motor oil to lube everything.

I have a 2353 that I have had since 1976 that developed some unusual noises.  It was making clunks and I could hear something that sounded like a motor shaft that needed lubrication.  I took the shell off and discovered one of the motors would not take oil.  Ended up using a can of WD-40 to clean out the oil hole and then lubed it with motor oil.  This is messy, so don't try it on the carpet.

One thing that will help is replace the original powdered iron rollers with new turned steel ones. This will reduce the sparking a lot.

In addition to what Chuck recommended, the 2023 type collector assembly(2023-22/2023-46) is a good retrofit for the old style 622 type rollers. The rollers rotate on the pin instead of the roller rotating in the bracket.