Question about mercruiser fuel pump

[jrusk]

I just recently bought a 1982 glastron with a mercruiser 470 in it. Don't really know much about boats but was told it was winterized. I put fresh fuel in it and took it out on Saturday. Ran great for about 15 minutes then started to surg and die. Would start up and run at idle and then backfire and die. After a bit would not even run at all. I was told to check the fuel filter. It looks OK but the question I have is, I have the fuel filter open and out, when I crank the engine over should'nt fuel flow out at the base of the fuel pump? Nothing at all comes out. Put small amount of gas in carb throat and it fired right up. Is there any way to check the fuel pump or should I replace it. Thanks in advance.

Jim

 

[Haut Medoc]

Re: Question about mercruiser fuel pump

Welome to iboats.....
Does it have a water separating fuel filter & if so, have you changed it?.....
It looks like an oil filter & will be located near the fuel pump.....​

 

[ziggy]

Re: Question about mercruiser fuel pump

I have the fuel filter open and out, when I crank the engine over should'nt fuel flow out at the base of the fuel pump? Nothing at all comes out.

there should be three holes on yer fuel pump.
one for in from the fuel tank
one for out to the carb.
and one that is out up to the flame aresstor or carb. this one is for safety. if the diaphram in the fuel pump rupturers, the fuel is routed up to the carb so the leak is captured by the carb and not leaking into the bilge of a boat..... so this outlet will not have output, normally......

 

[Haut Medoc]

Re: Question about mercruiser fuel pump

If it is not gunk & water in the fuel/water separator, then here is the next step....
http://forums.iboats.com/showthread.php?t=167561
Courtesy of Don S.......​

 

[sarantis]

Re: Question about mercruiser fuel pump

If you want an easier test put a tranparent flexible hose from the tank output to the input of the water separator .Go for a run with a friend that will watch ALL THE TIME the gas flowing through the hose.If you see vacuum bubles becoming biger and bigger you problem is bad fuel or clogged screen at the tank output or the antisiphon valve.In this case you will also notice that the hose will get supressed.If the flow is normal put the hose from the output of the pump to the carb inlet.(Be very carefull.This Kind of hose is not safe if it touches hot parts of the engine).To adjust the hose to the pump you can take out the racor of the carb and put a common fuel conector with the same turns(like the antisiphon valve or that at the entry of the water separator.I hope you 've changed it.GOOD LUCK

 

[jrusk]

Re: Question about mercruiser fuel pump

Thanks all. It looks like there is no water seperator. There are three holes, One comes from the tank, one goes up to the carb and a clear one that also goes up to the carb. When I crank the engine over without the fuel "filter" in there is nothing coming out.

Jim