BBCLiberator

iTrader: (2)

Went out tonight did some swimming hanging out etc. Went to leave, as always I started the boats and climbed up front to pull the anchor, as I was doing this the engine died, which isn't normal at a 1200rpm high idle . Initially I though my kids pulled the lanyard or something, but it sputtered out. I knew I had spark since the engine was trying but only if I really pumped the gas and eventually had nothing once the diaphragm in the fuel pump bled down all the way. Held onto the fuel pump (electric) and felt nothing, $hit. Followed the power wire to the port side bellhousing area where it plugs into some type of sensor/terminal with three connections, I assume this is the trigger for the fuel pump that senses the engine turning and kicks the fuel pump on??? I took the lead from the the fuel pump that was connected to this and grabbed the closest power, the distributor hot, and touched them together and voila, fuel pump kicked right on.

I was with my family so I didn't have to much time as it was getting dark so I cut the wire near the pump and hard wired the pump to the starter solenoid to get back in and ran the 12 miles back and disconnected it.

This started life as an OMC 502 package that i've pretty much deleted anything OMC related, ignition etc. I put a new fuel pump on last year, and based on the ride back in it's definitely good. It's a carbed motor so it's a low pressure pump.

1) What is the "sensor" or terminal the power is connected to on the port side rear near the bell housing? Could that be it?
2) I didn't get to check the relay or anything since it was dark when I got back just in time to have it pulled out for the night, but is there anything else I should look at??
3) I did push all the breakers and that did nothing.

If this ruins my weekend plans I may have to lose it Seems like this should be an easy fix, but you know how that goes.

As always any help or insight would be appreciated!!!!

87MagnumII

I've had a similar issue to you. I'm not sure how you are setup but mine runs off of a relay that is wired to the oil pressure switch. It also has an inline fuse between the relay and the pump. Mine started blowing the fuse to the point I couldn't even idle in. Mine ended as a bad pump that would run if jumped over but was drawing to much for the fuse. It's gotta be something simple such as the trigger you mentioned that I would guess senses oil pressure and allows the pump to run. I know you said you checked breakers but give it another look and see if there is a fuse wired into the pump as well somewhere back there. Remember to keep it simple.

c_deezy

iTrader: (1)

The 'sensor' you are talking about should be a Hobbs switch, should have a common, NO and NC. It's so your fuel pump doesn't keep running when the engine dies, it should be in an oil passage and when the oil pressure builds it completes the circuit to your fuel pump.

BBCLiberator

iTrader: (2)

Thanks guys, I know I had good oil pressure on the ride back in so I'll start there with the sensor and this time I'll have more than a few minutes and I'll be armed with actual diagnostic tools...which usually helps. Hopefully I can figure it out quick, the marina would laugh their a$$ off if they see my hack job using first aid kit tape to hold my wiring together, but when you don't feel like getting stuck in the dark with a 4 year old and 1 year old waiting for tow-boat us, it's amazing how quickly you can Macgyver something together. If only i'd figured out how to incorporate some gum, it would have been official "Macgyvering"

At least several people at the place we were hanging out stopped to see if we needed help, boating people are generally good people.

picklenjim

Not saying now beings the weekend is coming up but down the road you ought to concider taking off all the electric pump crap and go to a mechanical pump.

BBCLiberator

iTrader: (2)

Gen V block, that ain't happenin'

picklenjim

Sure ya can. Switch to the sea water/fuel pump design. That's what merc did when they switched to the gen 5's. Used these from '92 to '99. If you watch around you can find them used for around $200, sometimes less.
Here's what they look like:
http://www.ebay.com/itm/NEW-Mercruis...21e98b&vxp=mtr
Just say'n, electric fuel pumps suck. Best to stay away from them if you can. I quess it had that because it started as an OMC.

BBCLiberator

iTrader: (2)

Interesting, I didn't know that. As you state, if OMC did it, it was probably a bad idea

And I'm with you on the electric pump thing, just didn't know that was an option.

Budman II

iTrader: (1)

BBC, there have been a few posts out there complaining about the mechanical pumps mounted on the seawater pump. There is an oil reservoir that has to be changed regularly, per the Merc manuals, but no plug to drain it. A lot of guys installed their own drain plug to help with this. Another bad thing about this design is the fact that if the fuel pump diaphragm fails (and it probably will), the reservoir gets filled up with gas. I think a few guys have managed to adapt a better aftermarket fuel pump to use the Merc actuator arm so that they could be installed on this system. Do a search and you will find the thread.

I would start by jumping the oil pressure switch to see if it sends power to the pump. That would probably isolate that as the problem. You could also run a DVM across the leads on the switch and have someone spin the motor over to test it.

I carry a spare pump on board with me for such an emergency. Standing on your head in the bilge beats paying for a tow back. Keep plenty of rags on board too to mop up any spilled fuel. I also keep an electrical kit with crimpers, pliers and solderless terminals. My boat might pick up 3 mph if it weren't for all the crap I have stored on board!

BBCLiberator

iTrader: (2)

Got it fixed, boaters value in wyandotte pulled the part out of an aftermarket fuel pump kit and sold it to me for $20, it's installed and fixed my wiring from last night, all is well. Last night I put together a better tool kit...it's on the boat now