Description of Problem

Cause of Problem

Solution of Problem

Engine will not start

Out of fuel

Fill tank with fuel

Wrong type or poor quality fuel

Replace fuel

Carburetor not primed

Prime carburetor

Glow heater not charged

Charge glow heater

Bad glow plug

Replace glow plug

Engine flooded

See Flooding

Engine too hot

Allow engine to cool

Carburetor set incorrectly

Readjust carburetor

Blocked exhaust

Clean or remove debris from exhaust system

Air filter clogged

Remove and clean air filter

Starter will not retract

Broken spring

Replace recoil assembly

Starter hard to pull

Engine is flooded

See flooding

Engine is seized or locked up

Take engine apart

Engine starts then stalls

Idle set to low

Increase idle speed

Bad glow plug

Replace with new

Low-speed mixture too "rich"

"Lean" low-speed mixture

Low fuel tank pressure

Check for blockage in fuel pressure line.

Engine overheated

Allow engine to cool down

Engine sluggish or poor performance

High-speed mixture set to "rich"

Lean out high-speed mixture

Leaking glow plug

Tighten or replace glow plug

Bad glow plug

Replace glow plug

Old or dirty fuel

Replace with new fuel

Carburetor dirty or blocked

Clean carburetor, check for blockage

Engine overheating

Stop running and richen fuel mixture

Slipper clutch set too loose

Tighten slipper clutch

Tires not glued/wheel pins fell out

Glue tires/replace wheel pins

Engine over geared

Use lower gearing

Bound up drive train

Check drive train, and make it free

Engine worn out

Replace piston/sleeve and check connecting rod

Engine overheating

High-speed mixture to lean

Richen high-speed mixture (counter-clockwise)

Cooling air flow is blocked

Cut holes in body to allow air flow

Nitro content too high

Run nitro content between 10-20%

Fuel not containing correct lubricants

Purchase a higher quality fuel

Excessive load on the engine

Check for bound up drive train

Low-speed mixture too lean

Richen low-speed mixture

For boats only

Clogged cooling head

Check water cooled head for clogging

Engine stutters or hesitates

High or low-speed mixture too lean

Richen high first then low

Engine overheated

Stop engine and let it cool down

Bad glow plug

Replace with new

Engine stall as soon as you give it gas

Bad glow plug

Replace with new

Low-speed mixture too lean

Richen low-speed mixture

High-speed too rich

Lean high-speed mixture

Engine stalls when I let go of throttle

Idle set too low

Increase idle

Engine stalls for no apparent reason

Bad glow plug

Replace with new

Engine overheated

Shut off and let cool down, richen high-speed

Debris in fuel line

Remove and retry

Poor fuel tank pressure

Check hose foe clogging