Marinette Boat Forum

Oil pressure switch is the way to go better safety and you can pick one up at a local parts house.

You will also need I think a 1/8 npt T one male end for intake side and two FM for oil sending unit and the new oil pressure switch. Wire hot from key to one side hot with fuse all the time and hot to pump works well. Good luck!

Stupid question (total engine novice) but won't having the circuit on the oil pressure switch make it harder to start? (not much oil pressure when cranking)

Or do I have 2 hot wires, one through the oil switch & one that hits when the starter is engaging (turning key to start) - I assume that is what you mean

I also think the pressure switch is the best method.

As far as the pressure switch , the carbs have fuel in the bowls for startup and also as you turn the engine over oil pressure is created.

Yep you got it. Three wires one marked s it is normally closed until the units see 2 to3 psi of pressure then it's normally open side closes and the s side goes from closed to open. Metal head is right you have enough in the carb bowl to start anyway.

I would have to disagree that there would be fuel left in the carb.
If I let mine set for a month there is no fuel left in the carb. You have to crank the sh&t out of it get fuel back into the carb. I believe FastJeff had a system of adding a electric fuel pump to act as a primer pump only. That being one electric pump used as a tempary pump to prime both engines.
Someone care to make a diagram for using a electric fuel pump in place of the original mechanical pump?

If mine does not start on the first 5sec crank the second has built enough pressure that the pressure switch will close and run the pump until it looses pressure. Have you ever checked your float level and are you running the 1409?

My carbs were empty after letting the boat sit for only a week! And every damn time! My neighbors with their plastic boats never had that problem, so I guess it's related to the aluminum hull?

After using a boost pump system (T'eed into the carbs with a check valve to prevent back flow) I eventually went to electric fuel pumps instead of the mechanical pumps with a bypass switch to run the pumps when oil pressure was not present. (The bypass switch should have been a momentary type, and I've advised the new owner to make that change. It's necessary, I think, to be USCG legal.)

If you'll want to go this way, you'll need a marine approved electric pump, and a normally open oil pressure switch. (Oil pressure, it completes the ground circuit, turning on the pump.) The bypass switch does the same thing, taking about 5 to 10 seconds to fill an empty carb.

Additional items: A simple 1/4 inch aluminum plate was used to block off where the mechanical pump went. Being anal (hah!) I used a relay to power the fuel pump directly off the 12 volt connection at the starter solenoid. To trigger the relay, I connected it to the ignition power wire at the ballast resistor.

Note: Why the relay? I didn't want the oil pressure switch contacts to handle the amps the pump requires.

Let me know if you want to do this and need any additional help.

Jeff

Jeff did remind me one more thing. I used airtix p/n cv8000 check valve after the pump to hold fuel in the line to the carb.

Jeff Monday wrote:

" Have you ever checked your float level and are you running the 1409?"

I am running rebuilt Carter AFB's and yes the floats are set to the correct specs
bill