Test 71 - Check Spark Plugs; Test 72 - Check Engine / Cylinder Leak; Down Test / Compression Test - Generac Power Systems 10 kW LP Repair Manual

sEctioN 4.4
DiaGNostic tEsts
Figure 29. Checking Engine Miss
RESULTS:
1. If no spark or very weak spark occurs, go to Test 73.
2. If sparking occurs but engine still won't start, go to Test 71.
3. When checking for engine miss, if sparking occurs at
regular intervals but engine miss continues, go to Test 20.
4. When checking for engine miss, if a spark miss is readily
apparent, go to Test 74.
teSt 71 – check Spark pluGS
DISCUSSION:
If the engine will not start and Test 70 indicated good
ignition spark, perhaps the spark plug(s) are fouled or
otherwise damaged. Engine miss may also be caused
by defective spark plug(s).
PROCEDURE:
1. Remove spark plugs and clean with a penknife or use a
wire brush and solvent.
2. Replace any spark plug having burned electrodes or
cracked porcelain.
3. Set gap on new or used spark plugs as follows:
kW
Engine size
rating
410 cc 8 kW
530 cc 10 kW
990 cc 10-17 kW 0.040 inch
999 cc 20 kW
RESULTS:
1. Clean, re-gap or replace spark plugs as necessary.
2. If spark plugs are good, refer back to flow chart.
Page 136
recommended
Plug Gap
Plug
0.030 inch RC14YC
0.030 inch BPR6HS
RC14YC
0.030 inch RC12YC
Part 4
NORMAL
PRE-IGNITION
Figure 30. Spark Plug Conditions
Figure 31. Checking Spark Plug Gap
teSt 72 – check enGine / cylinder leak

doWn teSt / compreSSion teSt

GENERAL:
Most engine problems may be classified as one or a
combination of the following:
• Will not start
• Starts hard
• Lack of power
• Runs rough
• Vibration
• Overheating
• High oil consumption
DC CONTROL
MISFIRES
DETONATION