Introduction: Briggs & Stratton Low Oil Pressure Indicator, V-Twin

I have two lawn tractors with the Briggs & Stratton v-twin engines. I recently had to replace the sump gasket on one of them that caused a serious loss of oil. Neither one came with a low oil pressure indicator. In this instructable I am adding this warning light to my Allis Chalmers tractor.

Step 1: Tools and Materials

For this installation you will need:

1 ea. Easy-install street elbow, 1/8" NPT. McMaster Carr #5021T52

1 ea. 1/8" NPT extension, McMaster Carr #50785K25

1 ea. 12VDC LED indicator lamp. McMaster Carr #2779K5

1 ea. PS160 pressure switch, 4psi normally closed, Standard Motor Products.

5' of 18ga white primary wire.

3' of 1/4" wire loom, split poly.

Thread sealant

9/32" 4-point socket. McMaster Carr #5544A86

5/16" hex bit

Sending unit socket, K-D Tools #2569, an adjustable wrench may work also.

22-18 wire terminals

5/16" drill bit

Step 2: Install the Indicator Lamp

In an appropriate location where it can be seen by the operator, drill a 5\16" hole. Insert the lamp and fasten to the panel with the supplied push-nut.

You will need to locate a switched power supply to supply voltage to the lamp. One that is only live when the key is on. You can use the indicator lamp as a test light for this. I mounted the lamp next to the hour meter and that is where I tapped into the harness using a piggyback terminal to replace the existing female spade terminal on the + side of the hour meter. In the photo, the lamp is the white gizmo with red and white wires. Perhaps the light switch might work as a switched power supply also. Attach the white 18 ga wire to the lamp with a butt connector. This wire will run down to the switch that we will install. Cover the wire with the poly loom to protect it from chafing.

Step 3: Drain the Oil

Drain the oil and remove the oil filter.

Step 4: Remove the Pipe Plug

I needed a 9/32" 4-point socket to remove the plug. Yours may be a different size, double-check before you order a socket.

Step 5: Install the Fittings

Apply a small amount of thread sealant to the male thread on the brass fittings. Screw the old pipe plug into the brass extension to reduce the chance of it deforming when installing. Tighten this fitting into the engine, remove the plug and discard.

I chose the easy-install street elbow as it fits into a tight space nicely. Thread this fitting into the brass extension. Tighten it with the 5/16" hex bit aligning the side port to allow for the switch install.

Step 6: Install Switch

Screw the switch into the brass elbow with a sending unit socket or adjustable wrench. Crimp a female spade terminal onto the wire and attach it to the switch.

Install a new oil filter and refill the crankcase with oil.