Sportjet electric fuel pump modification!

[Pickles]

I was wondering if anyone has modified their 175 sportjet yet with a momentary switch to prime engine yet, and if so did you notice a big difference in cold starting!

[WaterDog]

Where do I find a "momentary" (what ever that is) switch? I pulled out my service manual and it looks to be an easy mod. I plan on doing it, just need to find the time and that switch.

Here is the switch

[ 12-14-2003, 08:35 AM: Message edited by: WaterDog ]

[Silver Hilton]

What's up with this? I am told that I have priming capability from the factory, triggered by pushing the key in, but I can't say I notice any particularly profound effect. Is this a Tim the Tool Man Taylor more power type of enhancement?

[Pickles]

Silver Hilton:

If you read the Stevens Marine Boat Doc Forum thread, The Boat Doc states that the electric fuel pump only runs while the engine is cranking. Pushing in on the key does not prime the engine. This mod is too have a way of priming the system prior to cranking the engine, therefore eliminating hard start conditions. Currently power to the electric fuel pump is wired to the starter solinoid. The mod is too remove this power wire, then rewire the fuel pump power through a momentary switch with a 3 amp fuse. This way you can prime your engine prior to trying to start it.

[Tilla]

A momentary (monostable) switch should operate the pump only when it is pushed. When you let go it shuts off. Similar to your windshield washer fluid switch.
This is different from a maintained switch (bistable) like your headlights.
Just in case anyone was wondering. [img]graemlins/idea.gif[/img]

[1pump]

The danger with a momentary switch that's controlled manually is flooding the engine if you close the circuit for too long.

Momentary switches are available just about everywhere, and you can get a toggle version if you prefer that to the push button. Just make sure it's momentary-on vs momentary-off.