Merc 470 Fuel Pump Problem?

[stonyloam]

3 to 7 should be fine. You will probably have to "T" in the oil pressure switch. There should be three pins on the oil switch. Common that goes to the relay. One that is normally closed that goes to the start terminal on the slave, to activate the relay during starting ( not the coil side), and one normally open that goes to the ignition ( the choke wire is a good place to pick that up). The large "hot" terminal on the slave is a good place to pick up power to the relay for the pump, or directly to the battery if it is closer. I used a similar relay for my Petronix. I mounted it using one of the valve cover bolts, worked fine.

 

[SDSeville]

I just spoke with Mercruiser again this morning regarding returning the 2nd pump. They apologized and said that this problem is much more common than I was told earlier. They said that they have been having trouble with their suppliers for about the past year and have been receiving many pumps that put out too much pressure. They explained that they recently purchased a machine that allows them to test the pressure on each pump before sending them out to the dealers and many of the pumps are failing.

Mercruiser also said that other manufacturers are having similar problems, likely due to the same suppliers. They gave the example that they told one customer to go ahead and buy a Sierra pump after multiple Mercruiser pumps had failed. The Sierra wound up putting out too much pressure also.

 

[stonyloam]

Sounds like electric is the way to go.

 

[SDSeville]

3 to 7 should be fine. You will probably have to "T" in the oil pressure switch. There should be three pins on the oil switch. Common that goes to the relay. One that is normally closed that goes to the start terminal on the slave, to activate the relay during starting ( not the coil side), and one normally open that goes to the ignition ( the choke wire is a good place to pick that up). The large "hot" terminal on the slave is a good place to pick up power to the relay for the pump, or directly to the battery if it is closer. I used a similar relay for my Petronix. I mounted it using one of the valve cover bolts, worked fine.

What happens with the overflow tube that used to go to the back to the fuel pump?

 

[stonyloam]

I am not sure, but that tube was there in case the diaphragm ruptured the prevent fuel from spilling into the bilge. With no diaphragm to rupture it would not be needed, so I guess you would just cap the tube off at the carb.

 

[SDSeville]

Installed the electric pump and it seems to be working great. It runs at about 4 to 5 PSI and my boat has never been able to idle so smoothly at such a low RPM. I will take her out Sunday and let you know how it goes.

It wasn't as cheap as it 1st seemed. The pump (USCG approved) was only $72 but after the oil pressure switch and everything else it was about the same price as an OEM mechanical pump.

 

[SDSeville]

Success...at last!!!! This electric pump works unbelievably. It idles smoothly below 1000 rpm for the 1st time since I have owned it and I can go as slow as I want through no wake zones forever without worrying about smoking or stalling. I guess the fuel pump has been bad since I bought this boat.

An added bonus is that my warm start problems are completely gone. Turn the key and it starts in half a second every time...with no special tricks. I have been fighting what I had thought was vapor lock for years and had a real tough time starting when warm. I had to start at 1/4 throttle, turn the key, ease the throttle slowly all the way to full throttle, continue to crank for about 7 seconds, then slowly ease the throttle back and it would start with a cloud of smoke. It felt just like it was flooded. Well...it was. The bad fuel pump was pumping extra fuel up the overflow hose and into the carb and it flooded at low rpms and every time it was turned off.

I haven't even been able to ski or wakeboard the past couple years because I was the only one who could start my boat. Now, it is just like starting a car....turn key, engine starts -- what a concept!

 

[thewaxmania]

I know this is an old thread, but I'm dealing with the same issues finding the right pump and I FINALLY came up with a Carter M60337 and its rated for 5-6.5psi at 25 gph at 1800 rpm. My original pump looked exactly like yours and I also have a fiber gasket/spacer on the pump currently. Did anyone mention if the Carter units were similarly afflicted with 15psi pressure problems?

 

[SDSeville]

The mercruiser rep told me he referred a customer to Carter after a couple bad merc pumps. The customer called back and said the Carter was bad too. I would really consider electric.

 

[thewaxmania]

Well, I installed the Carter 60337 and it seams like I got a good one. The boat finally runs and its running well. No excess pressure problems. I will make plans for an electric unit for next season.

Thanks.

 

[SDSeville]

Well, I installed the Carter 60337 and it seams like I got a good one. The boat finally runs and its running well. No excess pressure problems. I will make plans for an electric unit for next season.

Thanks.

If the pressure is correct, there is no need to get an electric pump. That one should last a good long time.

Enjoy the rest of the season!!

 

[SeaRayClyde37]

Where did you get your electric pump. I have been struggling for weeks with my new Sierra mechanical one. Can you private message me with the details please????

 

[SDSeville]

Hi Clyde,
The pump is a Seachoice Goldflo low pressure (4 - 5.5 PSI) pump made by Facet. I just picked it up at my local Marina since I was in a hurry to get back on the water.


iboats carries several Seachoice pumps that should work and they are cheaper than what I paid. Here are a couple. Maybe someone who knows a little more than me can tell us which would be best.

http://www.iboats.com/Cube-sup-reg-s...iew_id.1161186
http://www.iboats.com/Cube-sup-reg-s...iew_id.1161183