1)
See section on "flooding" for details
on how to correct.
2)
Choke is closed when engine is hot.
2)
Find & fix cause for choke staying closed.
Look for no heat source, spring in backwards, or
something jammed or bent.
3)
No spark.
3)
Do complete tune up.
4)
No compression.
4)
Diagnose cause of no compression & fix.
5)
No fuel
5)
Check fuel delivery volume and pressure. Look for
clogged lines, filter, or pump. Check for kinked
or swollen fuel lines.
6)
No air.
6)
Check for clogged air filter, especially after
driving through muddy or dusty area.
7)
Too much air
7)
Look for big vacuum leak, such as broken hose,
blown gasket, bad power brake diaphram, bad PCV
valve.
Engine
starts, then dies within a few seconds.
1)
Choke is staying closed
1)
Diagnose and fix choke problem.
2)
Flooding
2)
See section on flooding.
3)
Power valve blown.
3)
Replace power valve.
4)
Venting system failure.
4)
Check out entire fuel system venting system,
inluding the vent valve on the carb, the charcoal
canister, all hoses & check valves in the
system, and any solenoids that trigger the vent
system to operate.
5)
Idle jet plugged up with dirt.
5)
Clean out the idle jet and any other dirt in the
carb.
6)
Idle air bleed plugged up or missing.
6)
Check idle air bleed. Clean or replace as
necessary.
7)
Idle cut-off solenoid not working.
7)
Check idle solenoid, especially for power to it
and ground to it, replace solenoid if necessary.
Engine
starts, then races for a few seconds and then
dies.
1)
Big vacuum leak somewhere.
1)
Find the vacuum leak & fix it. Also look for
wrong base gasket or one that is installed wrong.
If engine has been spitting back, it may have
blown out the base gasket or a gasket in the
carb.
Engine
starts OK, but then get real rough. Lots of black
smoke.
1)
Power valve blown out by spitback up through
carb.
1)
Replace the power valve.
2)
Slow flooding.
2)
See flooding section.
3)
Float sunk. (usually caused by spitback up
through carb.)
Hesitation
under light throttle: Deadspot & stumble.
1)
Vacuum leak somewhere, or hose off or hooked to
wrong vacuum fitting.
1)
Inspect hoses. Route and lead the hoses
correctly. Look for leak because of wrong base
gasket or it was installed upside down.
2)
Accelerator pump problems.
2)
Inspect and adjust pump stroke, pump plunger,
discharge nozzles and check valves. Inspect the
accelerator pump, look for swollen pump cup.
3)
Float level set very low.
3)
Set float to factory specs.
4)
Ignition timing retarded.
4)
Set to factory specs. Make sure advancing
correctly.
5)
Dirty idle jet or economizer jet.
5)
Inspect idle jets. Clean as necessary.
6)
Idle speed set too fast & mixture is too lean
(common!).
6)
Richen up the idle mixture, reset idle speed to
factory specs, then lastly reset the mixture
using the lean drop method.
7)
Idle cut-off solenoid not working, or no power to
it or no ground to it.
7)
Inspect & fix as necessary.
8)
Frozen or binding heated air inlet (stuck in full
hot or full cold position).
8)
Inspect & fix as necessary.
9)
EGR valve stuck on or coming on too early (hose
on wrong?)
9)
Inspect hose routing to EGR valve & inspect
valve. Replace as necessary.
Doggy,
runs rough, lots of black smoke at idle.
1)
Choke staying closed or partly closed.
1)
Fix choke or heat source.
2)
Slow flooding.
2)
See flooding section.
3)
Power valve blown (caused by engine spitting
back.)
3)
Replace power valve.
4)
No electricity or heat source to choke.
4)
Fix cause of no heat source or electricity to
choke.
Hesitation
under heavy throttle: Deadspot & stumbles.
May backfire or spitback.
1)
Defective accelerator pump.
1)
Look for dirt in pump nozzles, swollen cup from
bad gas, or check ball missing or stuck.
2)
Metering rods or power valve sticking or binding.
2)
Inspect and correct.
3)
Vacuum leak.
3)
Locate leak and correct.
4)
Float level setting very low.
4)
Reset to factory specs.
5)
Plugged up fuel filter, defective fuel pump, or
swollen or kinked lines.
5)
Inspect and replace parts as necessary.
6)
Secondary air valve set wrong.
6)
Check & adjust the secondary air valve
spring.
7)
Ignition timing retarded.
7)
Set to factory specs. Check for proper advancing.
Dies
coming up to a stop sign, but idles ok.
1)
Bad or misadjusted BCDD (if equipped).
1)
Adjust to specs and replace it.
2)
Bad throttle positioner or bad vacuum source to
it.
2)
Check throttle positioner with a vacuum pump.
Replace if defective. Replace any cracked hoses.
Make certain that the vacuum hose is connected to
the correct pipe on carb or on the thermal
switch. Make sure all related pipes have vacuum.
3)
Idle speed and mixture incorrectly adjusted.
3)
Reset to specs using Recarbco's method. See the
adjustment and installation instructions on our
website.
1)
Check exhaust. Look for plugged catalytic
converter, bad muffler baffle, kinked or crimped
pipe, dirt or other foreign matter in pipe.
2)
Clogged gas tank vent, or fuel venting system.
2)
Remove gas cap & see if performance improves.
If so clean or replace the gas cap. Check the
charcoal cannister, hoses to it & any check
valves. Check the electric vent valve on the carb
if there is one, & make sure it is getting
power at the right time.
3)
Ignition timing retarded
3)
Check timing at idle and also for full advance
when revved up. Look for bad or loose hose, hose
hooked up to wrong pipe on distributor, bad
thermal switch, leaking vacuum advance can on the
distributor, a worn breaker plate, worn
distributor shaft, sticky weights, point gap
closed up, etc.
4)
Clogged air filter
4)
Replace air filter.
5)
Choke not opening
5)
Fix choke or heat source problem.
6)
Secondary not opening.
6)
Check the lockout: secondaries won't open unless
choke is coming off all the way. Check for sticky
or bent shaft or linkage. If air valve type
(Rochester), check the spring tension, the
plastic cam, & metering rods for dragging or
sticking.
7)
Wrong main jets or rods
7)
Check them. Replace if necessary.
8)
Dragging brakes.
8)
Fix brake problem.
9)
Low tire pressure.
9)
Increase tire pressure at least to factory
recommendations.
10)
Automatic transmission malfunction.
10)
Diagnose & fix automatic transmission.
11)
Wrong or malfunctioning thermostat in cooling
system.
11)
Replace thermostat.
12)
Blocked or leaking exhaust heat passage in intake
manifold.
12)
Remove manifold & fix it.
13)
Defective accessory (power steering pump, air
conditioning compressor, etc.) causing drag on
engine.
13)
Diagnose & repair or replace the accessory
unit.
14)
Wheels out of alignment.
14)
Have wheels professionally aligned.
15)
Poor driving habits.
15)
Reduce speed, quick acceleration, screeching
around corners etc.
16)
Float level much too high, or float partly sunk.
16)
Set to factory recommendations, & check float
weight, replace if necessary.
17)
Ignition problems or needs a tune up.
17)
Do complete tune up & physically inspect the
cap, rotor, wires, coil, plugs, points, etc. in
addition to checking on the scope.
(Note:
flooding is gas pouring out uncontrollably, it is NOT
hesitation!)
CONDITION
POSSIBLE
CAUSE
CORRECTION
Gas
pours out when engine is turned off.
1)
Charcoal cannister is saturated with gas.
1)
Replace the charcoal cannister.
2)
Vent valve is not functioning correctly.
2)
Replace the defective valve or fix other cause of
it's malfunctioning (like loose connection, etc).
3)
Kinked hoses in venting system.
3)
Replace the kinked hoses with correct kind.
4)
Stuck or blocked check valves in the vent hoses
or elsewhere in the system.
4)
Replace the check valves.
5)
Gas tank vent is blocked.
5)
Fix it or replace the gas cap if vent is in the
cap.
6)
Gas line located too close to a heat source (such
as a radiator hose or exhaust manifold).
6)
This causes the fuel to expand & be forced
past the needle & seat. Also, fuel can boil
in the carb if there are improper or missing
gaskets or spacers between the carb &
manifold. A heat riser stuck in the closed
position will also cause boiling and flooding.
Gas
pours out when the engine is running.
Note 1: often removing the carb from the manifold
& shaking it hard a couple of times will
effect a cure.
Note 2: if procedure in note 1 doesn't cure it,
the problems is almost always dirt or bad gas
getting into the carb. Carb will then need to be
disassembled to fix it.
1)
Dirt stuck on tip of the needle & seat.
1)
Clean the tip off carefully or replace the needle
& seat and clean the entire fuel system out.
2)
Idle speed is set too fast.
2)
Reduce the idle speed to factory specs. If it
will not idle slowly, the mixture is set too
lean, or the idle solenoid is not functioning
right, or there is a vacuum leak somewhere
(usually not in the carb).
3)
Idle solenoid is not functioning.
3)
Check for power & ground up to the solenoid.
Check the operation of the solenoid. Look for
dirt stuck in the solenoid or the passageways to
it.
4)
Fuel pump pressure too high.
4)
Check pressure. Use a regulator to control the
pressure or put on a new pump (don't use high
pressure type).
5)
Fuel pressure is fluctuating or
"pulsing" (common on Colts, Mitsubishi
& other Chrysler imports).
5)
Control pulsing with a regulator.
6)
Float is heavy or sunk.
6)
Replace float. Is often caused by spit-back up
through carb.
7)
Gas is very gummy, old, or has too much alcohol
or other chemicals in it.
7)
Clean bad gas out of carb. Clean out of fuel
system. Use only good quality gas.
8)
Sugar in the gas.
8)
Clean out the entire fuel system.
9)
Choke not working.
9)
Check cause of choke failure, choke pull-off
failure, or loss of heat to the choke.
10)
Needle not seated properly during initial fill.
10)
Try tapping the fuel inlet or needle & seat
area with the handle of a screwdriver. If this
doesn't work, unbolt carb from manifold and shake
it hard a couple of times.
11)
On Mikuni carb, the overturn ball fell out of
place.
11)
This is caused by the carb being overturned or
turned on its side. Remove top and reinstall the
ball.
12)
On carbs with externally adjustable float levels.
12)
Excessive adjustments have caused the seal to
break. Replace the seals.
