Check the following items carefully:
(1) Is the glowhead tight, and not leaking compression-is there(1 or more) copper gaskets fitted under the head and are they in good condition? Is the centre electode stem OK and not loose?
(2) Are ALL the holes in the sparaybar and carb clean and open-the hole in the gold anodised assembly where the fuel line attaches, the hole on the inside that feeds to the venturi itself, and the three tiny holes around the venturi
(3) Are there any air/compression leaks-where the venturi screws in to the plastic housing, at the front of this housing and at the back of the housing
(4) Is the plastic carb housing split or distorted?
(5) Is the collet at the front of the engine behind the prop driver done up tight-but not so tight as to distort the plastic housing?
(6) Is the backplate tight?
(7) Is the pressure nipple on the right side of the crankcase below the carb drilled out or sealed? If open, block it with a small piece of plugged fuel line
(8) Are the exhaust ports free of any burrs caused by improper use of tools?
(9) Are you using appropriate props (7x3, 7x3.5, 7x4) and appropriate fuel (min 20% oil, 15-30% nitro)?
(10) Is the needle itself undamaged-tapered tip not bent or snapped off?
(11) Is the fuel tank located appropriately-top on the same level as the needle valve assembly?

If all thes check out OK then the engine WILL run-no matter how old and/or worn [though if old and worn it may be harder to start and have less power than one in better condition]

'ffkiwi'