Merc 470 Fuel Pump Problem?

[SDSeville]

While I was testing my new water pump seals, I noticed fuel going up and down the overflow line from the carb to the fuel pump. The line was clear after the initial start and while the motor ran on muffs for about 20 minutes. However, as soon as I turned it off the line filled up with fuel. I couldn't really tell which way it was going, but at times it did appear to be going up to the carb. Does this sound like a bad fuel pump? If so, I am thinking this may have contributed to my difficult warm starts over the past few years.

 

[Bt Doctur]

fuel in the tube means the diaphragm has ruptured

 

[SDSeville]

fuel in the tube means the diaphragm has ruptured

Thanks for the quick reply Bt Doctor. Does iboats sell the pump I need?

 

[Eric 3.7LX Alpha 1]

Thanks for the quick reply Bt Doctor. Does iboats sell the pump I need?

Here you go:
http://www.iboats.com/mall/partfind...gd_poid=112251&gd_row=72&session_id=028555565

you can also try ebasicpower.com they do have a lot of 470 /3.7 parts as well, but the fuel pump is about the same price:

http://bpi.ebasicpower.com/mm5/merc...ch=3.7 &psrelevance=name,descrip,malterms,oem

 

[stonyloam]

Make sure the new pump arms match,and the gaskets are the right thickness. read this: http://www.breezeworks.net/cgi-bin/...forum=1&searchSort=dateDESC&ReturnPage=Search and this: http://www.breezeworks.net/cgi-bin/...forum=1&searchSort=dateDESC&ReturnPage=Search

 

[SDSeville]

Nice. Couldn't just be an easy buy plug and play. The guy at the local shop says he has the oe mercruiser pump. I wonder what that means. I thought the original was a Carter.

 

[stonyloam]

LOL, nothing is easy with boats. The main thing is that the arm does not press too hard on the cam, can cause too much fuel pressure or excessive wear on the cam. Might be plug and play, just jetting you know some folks have had problems with replacement pumps that were supposed to fit.

 

[stonyloam]

LOL, nothing is easy with boats. The main thing is that the arm does not press too hard on the cam, can cause too much fuel pressure or excessive wear on the cam. Might be plug and play, just jetting you know some folks have had problems with replacement pumps that were supposed to fit. If you have the older pump, there is a diaphragm kit for it http://www.mercruiserparts.com/Show...URETOR+ASSEMBLY,+FLAME+ARRESTOR+AND+FUEL+PUMP

 

[stonyloam]

So far I am not real impressed with the forum update........ Hope they get it worked out soon, can't edit from my Ipad, and what is with the double post? Guess everybody has problems.

 

[SDSeville]

It is not all bad. The forum has been down so much it has probably earned me a promotion. I am getting more done than I have in years. ...or since I discovered this forum.

 

[SDSeville]

How do I know if I have the older pump?

 

[NHGuy]

Go by year make and serial #

 

[SDSeville]

Just picked up OE Quicksilver fuel pump at the local shop. Looks like it should be plug and play after all. What sealant do you guys use on the fuel pump gasket?

 

[stonyloam]

AAARRRRRGGGGG Dang won't let me post!!!!! OK, none, per manual: Install gasket,install pump,torque to spec (20 ft. lb.).

 

[SDSeville]

Well, the Quicksilver pump is not an exact match. The inlet and outlet are on the same side, whereas they were on opposite sides on the original. I bought some brass fittings at the auto parts store to reroute in the inlet. The outlet is in the exact same spot as the original pump.

Also, the arm appears to be about 1/2" shorter than the original.

I will try to get this thing installed today and let you know how it works.

 

[SDSeville]

Well, that didn't work worth a darn. Installed new OE quicksilver fuel pump and it barely runs. Check out the video (sorry it is at an angle -- needed both hands to start the motor).. It barely starts and then floods out, smokes, and dies. Look at how much fuel is being dumped into the carb. I purposely spent $50 more for the OE pump to avoid problems. What could have gone wrong?

 

[stonyloam]

The arm is too tight on the cam and produces too much pressure. Don't run it again you may score the cam.

 

[SDSeville]

The arm is too tight on the cam and produces too much pressure. Don't run it again you may score the cam.

Did I get a bad pump or the wrong pump (merc part#861676A 1) ?

 

[Ceneves91]

no you need to install the spacing gasket or else the cam has too much pressure on the arm of the pump and thats why its dumping so much fuel into the carb

 

[SDSeville]

no you need to install the spacing gasket or else the cam has too much pressure on the arm of the pump and thats why its dumping so much fuel into the carb

The new pump came with the same gasket the old one had. It is about 3 times as thick as a regular paper gasket. Do I need something even thicker?