20739 Mercruiser NUT, JAM - MOUNTING BRACKET

Adjusting the Positive Pressure Regulator
Table 2
Parameter    Value    
Supply Natural Gas Pressure     83 to 172 kPag (12 to 25 psig)    
Supply Propane Gas Pressure    
69 to 145 kPag (10 to 21 psig)    
Table 3
Gas Pressure Calculation Formulas    
Parameter     Formula    
Supply Natural Gas Pressure     Fuel Supply Pressure = (46 - 29.92 + (altitude [feet] x .001)) x .4912 + 5 (1)    
Supply Propane Gas Pressure     Fuel Supply Pressure (FSP, psig) = (46-29.92 + (altitude [feet] x .001)) x .4912 + 1 (1)    
( 1 ) Altitude is required from the customerNatural Gas Positive Pressure Regulator
Turn the gas supply to the natural gas pressure regulator off.
Illustration 1 g03605338
(1) Low-pressure side port (2) High-pressure side port
Connect 1U-5470 Engine Pressure Gp or 198-4240 Digital Pressure Indicator Gp to the engine.
Connect the "High Pressure Side" of the gauge to the outlet port of the engine regulator upstream of the electronic fuel control valve.
Connect the "Low Pressure Side" of the gauge to the tee fitting of the balance line on the regulator as shown in Illustration 1.
Install the 8T-5160 Gas Regulator Setting Tool if necessary.
Turn the gas supply pressure back on. Start the engine and operate at rated speed and no load.
Note the pressure differential on the pressure gauge. Compare the measured value to the value obtained previously in the Special Instructions, "Calculate the Engine Pressure Regulator Differential (dP)" section. If the values match, proceed to Step 9. If the values are different while using the 8T-5160 Gas Regulator Setting Tool , proceed to Step 6. If the values are different and the 8T-5160 Gas Regulator Setting Tool is not being utilized, proceed to Step 7.
Use the 8T-5160 Gas Regulator Setting Tool to adjust the regulator spring pre-tension until the measured and calculated differential pressure match. Proceed to Step 9 after the values match each other.
Shut down the engine and turn off the gas supply pressure.
Remove the cap from the engine mounted gas pressure regulator.
Adjust the regulator by adjusting the nut and/or screw with a screwdriver or similar tool.
Replace the cap.
Turn on the gas supply pressure. Start the engine and operate at rated speed with no load.
Compare the differential pressure reading with the calculated differential pressure.
If the values match, proceed to Step 9. If the values do not match, repeat Step 7 to Step 8.ReferenceRefer to Testing and Adjusting, KENR6870, "Gas Pressure - Check and Adjust" for more information on adjust the regulator.
Replace the cap.
Stop the engine. Turn the gas supply to the regulator off.
Remove the lines for the differential pressure gauge and install the plugs back into the high and low side pressure locations.
Turn on the gas supply pressure and restart the engine.Propane Positive Pressure Regulator
Illustration 2 g03605476
(1) Point A (2) Balance lines kept separate (3) Natural gas emission Adjustment screw (4) Balance line 1/2 inch diameter (5) Propane gas emission adjustment screw (6) Propane gas regulator (7) Solenoid valve (8) Vaporized propane gas (High BTU gas) (9) Manual shutoff valve or Solenoid valve and Pressure switch (10) Natural gas (Low BTU gas) (11) Pressure switch (12) Natural gas regulator (13) Fuel actuator (14) Carburetor (15) 5.5 inch 5 inch H2O differential here to Point A (16) 1.5-3.0 in H2O negative differential from here to Point A
Ensure that the gas supply to the propane gas pressure regulator is turned off.
Illustration 3 g03606576
(1) Low-pressure side port (2) High-pressure side port
Connect 1U-5470 Engine Pressure Gp or 198-4240 Digital Pressure Indicator Gp to the engine.
Connect the "Low Pressure Side " of the gauge to the port at the outlet of the propane regulator. The port should be upstream of the electronic fuel control valve and the propane emission adjustment screw as shown in Illustration 3.
Connect the "High Pressure Side " of the gauge to the tee fitting by the balance line on the propane regulator as shown in Illustration 3.
Install the 8T-5160 Gas Regulator Setting Tool if necessary.
Turn the gas supply pressure back on. Start the engine and operate at rated speed and no load.
Note the pressure differential reading. The reading should be in the range of 1.5-3.0 inches in H2O.
If the values match proceed to Step 9.
If the values do not match while using the 8T-5160 Gas Regulator Setting Tool , proceed to Step 6. If the values do not match while not using the 8T-5160 Gas Regulator Setting Tool , proceed to Step 7.
Use the 8T-5160 Gas Regulator Setting Tool to adjust the regulator spring pre-tension until the measured and calculated differential pressures match. Once the pressures match, proceed to Step 9.
Shut down the engine and turn off the gas supply pressure.
Remove the cap from the engine mounted gas pressure regulator.
Adjust the regulator with the nut/screw with a screwdriver or similar tool.
Replace the cap.
Turn on the gas supply pressure. Start the engine and operate at rated speed with no load.
Check the measured differential pressure. If the reading is between 1.5-3.0 inches H