Clean air filter

Clean fuel filter

Inspect fuel tank, line and engine for poor seals

Return needles to factory-recommended settings

Replace glow plug and/or change glow plug filter

Adjust idle-speed screw clockwise

Lean out low-speed mixture

Richen low-speed needle

Take clutch apart and fix the problem

Tighten glow plug

Replace glow plug

Seal engine with high temp sealer

Clean or replace bearings

Lean out low-speed mixture

Replace clutch spring/shoes

Install a hotter plug

Seal engine with silicone

Richen low-speed needle

Richen high-speed mixture

Clean fuel filter

Replace piston and sleeve