Description
Description
Description
Description
Description
Problem
Problem
Problem
Problem
Problem
Solution
Solution
Solution
Solution
Solution
Engine will not start
Out of fuel
Fill fuel tank
Improper or contaminated fuel
Replace fuel
Glow starter not charged
Charge glow starter
Glow plug bad
Replace glow plug, see “Glow Plug Problems” section.
Engine flooded
See “ flooding” section.
Engine overheating
Allow engine to cool, richen fuel mixture, check airflow
Carburetor incorrectly adjusted
Readjust carburetor
Exhaust blocked
Clean exhaust system
Air cleaner blocked
Clean air filter
Starter will not pull
Engine is flooded
Clear excess fuel, see “flooding” Section.
Rope is jammed
Repair starter.
Engine seized
Examine engine for damage.
Engine starts and
Idle speed set too low
Increase idle speed.
then stalls
Air bubbles in fuel line
Check for holes in the fuel line.
Glow plug is fouled
Replace glow plug, see “Glow Plug Problem” section.
Engine is overheated
Allow engine to cool, richen fuel Mixture, check airflow
Insufficient fuel tank pressure
Replace pressure hose- clear
Blockage at exhaust header fitting
Check flow to and from the tank.
Engine sluggish /
High-speed fuel mixture is too rich
Set high-speed mixture to a leaner setting
poor performance
Leaking glow plug
Check glow plug gasket
Fuel bad or contaminated
Replace fuel
Carburetor dirty or blocked
Clean Carburetor
Engine overheating
Stop the engine- find the cause
Engine over geared for application
Use a lower gear ratio
Clutch slipping
Replace clutch shoes
Bound up drive train
Find the bound item and repair
Engine overheats
High-speed fuel mixture is too lean
Richen high-speed mixture
Cooling air is being blocked
Get air to the head
Excessive nitro in the fuel
Use fuel with lower nitro
Excessive load on the engine
Check for bound up drive train
Low-speed mixture too lean
Richen low-speed mixture
Engine hesitates or
High-speed mixture too lean
Richen high-speed mixture.
stumbles
Low-speed mixture too rich
Lean low-speed mixture.
Engine overheated
Stop the engine and find the cause.
Air bubbles in fuel line
Check for holes in fuel line.
Glow plug fouled
Test or replace plug
Engine stalls instantly
Glow plug fouled
Replace glow plug.
when throttle is fully
Low-speed mixture too lean
Richen low-speed mixture.
opened from idle
High-speed mixture too rich
Lean high-speed mixture.
Engine stalls while
Fuel level is low
Add fuel
driving around turns
Idle speed set too low
Increase idle speed.
Care and maintenance
5
CARE AND MAINTENANCE
When you are finished racing for the day, drain the fuel tank. Afterwards, energize
the glow plug with your glow plug starter and try to restart the engine in order to burn
off any fuel that may remain inside the engine. Repeat this procedure until the engine
fails to fire. Try to eject residue while the engine is still warm.
Finally, inject some corrosion inhibiting oil, and rotate the engine to distribute the
oil to all the working parts. Do not, however, inject the oil into the carburetor, for it may
cause the O-rings inside to deteriorate.
When cleaning the exterior of the engine, use WD-40. Do not use gasoline or any
solvents that might damage the silicone fuel tubing.
Glow Plug Problems
The glow plug in your engine is an inexpensive consum-
able item which must be replaced periodically to maintain peak performance and
starting ease. Most often, any starting problems or erratic performance can be traced
back to the glow plug. The glow plug should also be checked if the engine’s accelera-
tion and top speed performance suddenly becomes flat.
The only sure way to test for a faulty glow plug is simply install a new one to see
if the problem goes away. Remove the plug from the cylinder head with a 5/16” nut
driver. Make sure there is no dirt or debris on top of the head which could fall into the
engine. Do not lose the copper gasket which seals the glow plug. Touch the glow
plug to the contacts of the glow plug starter. All of the coils should glow white. Some-
times the first few coils will not glow while the rest are bright, most likely indicating a
bad plug. If the glow is dim orange, then the glow starter battery should be replaced
or recharged.
Flooding
You may accidentally flood the engine at some time. Symptoms of a
flooded engine include difficulty starting and muffled sounds coming from the ex-
haust. Remove the glow plug with a 5/16” nut driver and then remove the air filter.
Turn the engine upside down to drain any excess fuel out of the combustion chamber
and carburetor. Turn the vehicle back over and install the glow plug. The engine
should start and run normally.
Cleaning the air filter
When the air filter starts to get dirty, do the
following steps.
Step 1
Clean the foam with fuel. Do this by pouring a little
fuel in a small can and kneading the filter in the fuel. When
it looks cleaner, then dispose of the fuel.
Step 2
Dry the filter. Squeeze out the fuel with a paper
towel until it’s dry.
Step 3
Apply Associated’s #7710 Foam Pre-Filter Treat-
ment to help keep the dirt out. Dab the treatment all around
the filter, put the filter in a plastic sandwich bag, and knead
it until the filter is saturated, but not soaked.
Troubleshooting your engine
6
Fuel Mixture
The fuel mixture is the largest variable you have to control while
operating your engine. Fuel brand, ambient temperature, and humidity all effect how
your mixture should be set. If the engine runs great one day but runs rich or lean the
next day, it is probably the result of a change in the air quality and temperature. This
should be expected and adjusted for.
Cooling Problems
Engine overheating is most often caused by running the en-
gine too lean or because the cooling air for the cylinder head is blocked. If the mixture
is too lean, simply allow the engine to cool, richen the mixture and try it again. Bodies
must have holes cut in them to allow for cooling air to circulate over the surface of the
cylinder head. On most bodies, it is a good idea to cut part of the windshield out and
part of the back window to allow for additional cooling.
Troubleshooting Chart
3
Foam Pre-filter
Treatment
