Oil Pressure Switch Necessary with the Sniper EFI?

[Kareo]

I am almost done with the process of installing a Sniper EFI on my 1979 Mercruiser 260. It's on and working, I am just finishing up wiring the fuel pump.

Most posts and videos I've seen say that you need to wire in an oil pressure switch to be USCG compliant.

The actual regulation reads:

Electric fuel pumps are not permitted to be operable except:
(1) during the engine starting procedure, and
(2) while the engine itself is operating.

It says that normally to achieve that, you use an oil pressure sensor (but says nothing about it being a requirement)

The Sniper is capable of controlling the fuel pump, and other than a 5 second prime when you turn it on, the fuel pump doesn't run when the engine isn't running. I believe even the 5 second prime can be shut off in the software.

I have already installed an oil pressure sensor, but the wiring gets complicated if I want to install that, a push button to manually prime the pump, and still allow the Sniper to control the pump as well.

It seems to me that if the Sniper already automatically shuts off the pump when the engine isn't running, that by itself meets the coast guard regulations. Can I disable the automatic prime in the software, and go without the Oil Pressure Switch, and just wire in a momentary switch for priming during starting operations?

 

[jimmbo]

Is the Sniper itself, USCG compliant, as in does it have Certificates saying so?

 

[Kareo]

Is the Sniper itself, USCG compliant, as in does it have Certificates saying so?

Yes, the Sniper is USCG approved, as is the 12-920 Fuel pump they sell. I have used A1 fuel lines and approved fittings and hose clamps. As far as I can tell, everything in my new system meets the requirements, but I want to make sure the wiring on the fuel pump also is in compliance.

 

[dubs283]

Have no clue how the sniper system or associated ecm controls igniton/fuel

I do know that on mercruiser efi the ecm controls the fuel pump output through a relay, there is no oil pressure switch control. Mercruiser only used an oil pressure switch to control fuel pump operation on carbureted engines

Sounds as though, according to your post/info provided the sniper ecm does control fuel pump operation and an oil pressure switch is not necessary. Probably in your best interest to contact Holley and verify

 

[Scott06]

It seems to me that if the Sniper already automatically shuts off the pump when the engine isn't running, that by itself meets the coast guard regulations. Can I disable the automatic prime in the software, and go without the Oil Pressure Switch, and just wire in a momentary switch for priming during starting operations?

yes i would think that if you go off the blue wire (fuel pump 12 v supply in sniper wiring) that would meet the regulation If say the engine dies but key is left in run… the fuel pump should shut off. Thats what the oil pressure switch does. Would run that by holley.

why would you want to disable the prime snd then wire a momentary switch? One of the advantages of injection is the quick starts because it automatically primes and fuel is right there… leave the auto prime in place

 

[Scott Danforth]

All electric fuel pumps in a marine environment need to have an alternate switch that shuts down the pump. One is the primary ignition, the second is either from an oil pressure switch, alternator output, or ECM command

You want to make sure the pump is not running unless the motor is running

Keep the 5 second prime as that is acceptable. The manual prime button is not ABYC compliant

 

[Kareo]

yes i would think that if you go off the blue wire (fuel pump 12 v supply in sniper wiring) that would meet the regulation If say the engine dies but key is left in run… the fuel pump should shut off. Thats what the oil pressure switch does. Would run that by holley.

why would you want to disable the prime snd then wire a momentary switch? One of the advantages of injection is the quick starts because it automatically primes and fuel is right there… leave the auto prime in place

I'd prefer to leave the auto prime in place, just not sure that technically meets the USCG regulation since it does it automatically when the ignition is turned on. From a practical standpoint, it only primes for 5 seconds then shuts off, and you would normally be starting the boat at that point anyhow, so I don't see it as particularly risky. However, pushing a button on the dash right before starting will accomplish the same thing, so if I need to do that to stay in compliance I can.

 

[dubs283]

All oem sterndrive/inboard gas engines prime the system with the fuel pump upon key up.

Good practice to key on, engine off prior to cranking to start to allow for operator recognition of audio warning system and allowing the fuel pump to prime. Consider it a systems check

Agree with others as it's in your best interest to leave the key on prime function vs rewiring a manual switch.