Fuel Pump ?s

[Chad D]

Hi guys Im new here and have a couple of questions. Fist let me tell you about my self and my boat. Im 23 and just bought my first boat. My family had a prety nice Corect Craft up to about five years ago and against protest from the kids my parents sold it. My boat is a 1976 17ft MFG gypsy with a mercruiser 165 IL6 cyl. the boat is a project ( I know that cheep boats are expensive but I already have a $ that I will call it quits at and not cry too much). I bought the boat thinking that I just had to replace the floor however now that I have replaced the starter and have done a tune up I have found that I am not getting any fuel to my carb. I disconected the line from the carb and cranked the engine trying to get gas in a cup but not a drop. she will fire on a couple of clys on a little gas poured down the carb. so my question is can I use an auto fuel pump and if not what are the reasons why. thanks this is a great website and will come in helpfull as I put this boat back together

 

[Haut Medoc]

Re: Fuel Pump ?s

Welcome to iboats.....
You cannot use an auto pumo, though I know it is way cheaper....
Primarily because if the diaphragm fails, it will dump gas into the bilge creating a potentially explosive situation......
A marine pump will either have a sight glass, or a vent tube that will route the fuel back to the carb.
Do not use an auto pump!........ ​

 

[Chad D]

Re: Fuel Pump ?s

Thanks I had a feeling that it had something to do with the boat going boom I have one other question I have the fuel pump with the filter built in I have seen on most engines the pump is mounted with the filter on the botom. mine is mounted with the filter on top. Is it supposed to be that way with the engine I have or did someone who didn't know what they were doing put it on wrong. I ask that because I am not getting any fuel from the line that goes to the carb and both lines and all filters are clear

 

[ziggy]

Re: Fuel Pump ?s

well, i've got the same question.

my carter fuel pump on my '75 L6, is oem to the best of my knowledge. it's a single diaphram fuel pump, no sight glass, no fuel dump back to the carb. i just replaced my diaphram in my fuel pump with new one that i got at the mercruiser store. i think it was a quiksilver part, but may have been sirrea. the actual parts breakdown when i tore it apart is verbatum of the oem service manual. i do agree, absolutely no auto fuel pumps, but i would like to know the difference myself from it's auto counterpart in this perticular case. i also wonder if these fuel pumps would pass a uscg inspection. it's what my boat came with from the factory in 75.

chad d, yer filter on top is ok. mine is too. had a 72 L6 too, it was also on top. check the filter, it will catch conaminates. least mine does (is). also ya got a screen type filter at the carb. some crap will pass the fuel pump filter and make it's way up to the screen on the carb too.

ya can check yer fuel pump pressue to see if the pump is working. it's 3.5-4.5 psi. ya could also have restricions in front of the fuel pump. anti siphon valve, crap in the fuel tank pluging up the outlet from the fuel tank. might even need to release pressure if the vent is pluged up...just a few thoughts on that anyways.......

 

[Chad D]

Re: Fuel Pump ?s

Thanks, I thought that my line form the tank might have been clogged or something so I took it off of the pump and tried to siphon that line and fuel came through the line with out any problem. again both filters are fine. just trying to elimiate all other posibilities before I drop $120 on a new fuel pump.

 

[Don S]

Re: Fuel Pump ?s

The diaphram and/or the diaphram kit is the same for automotive and marine. It's the body of the fuel pump that is different. And that doesn't get replaced unless the fuel pump does.
So there is absolutly no reason to change the diaphram kit instructions. Nothing changes.
The pump MUST have a way to prevent fuel leaking into the bilge from a bad diaphram.

 

[ziggy]

Re: Fuel Pump ?s

i'll start by sayin sorry to chad d. i don't mean to hijack yer thread. but it contains pertant info to my question too and i can't seem to start my own thread and get the parts of this thread into my thread. so. sorry man. hope the info is pertant to yer rig too.

this is out of my service manaul.

(sorry the pics upside down)The pump MUST have a way to prevent fuel leaking into the bilge from a bad diaphram.

so how is this accomplished in the carter fuel pump? theres no sight glass, and theres no fuel dump back to the carb. and it's a single diaphram pump. my diaphram leaked. and it dripped into the bilge. i'm concerend. my boat was used before me. but in looking at my fuel pump, it looks to be a mercruiser pump. it's black and don't look repainted. so i assume i have the oem fuel pump.

 

[Don S]

Re: Fuel Pump ?s

so how is this accomplished in the carter fuel pump? theres no sight glass, and theres no fuel dump back to the carb. and it's a single diaphram pump. my diaphram leaked. and it dripped into the bilge. i'm concerend.

You should be concerned, you have a 1975 model, someone may have put an automotive pump on it back in the seventies. Since fuel pumps used to come unpainted from Merc, paint color is kind of a non issue. The fact that it did leak into the bilge for me would have been an indication it's time to get the proper MODERN new MARINE fuel pump with the safety feature built in.
You got lucky when yours leaked into the bilge, hope it doesn't decide to leak again !!!!

 

[freelunch]

Re: Fuel Pump ?s

i'll start by sayin sorry to chad d. i don't mean to hijack yer thread. but it contains pertant info to my question too and i can't seem to start my own thread and get the parts of this thread into my thread. so. sorry man. hope the info is pertant to yer rig too.

this is out of my service manaul.

(sorry the pics upside down)The pump MUST have a way to prevent fuel leaking into the bilge from a bad diaphram.

so how is this accomplished in the carter fuel pump? theres no sight glass, and theres no fuel dump back to the carb. and it's a single diaphram pump. my diaphram leaked. and it dripped into the bilge. i'm concerend. my boat was used before me. but in looking at my fuel pump, it looks to be a mercruiser pump. it's black and don't look repainted. so i assume i have the oem fuel pump.

If that is the pump on your boat it is NOT an aftermarket pump. That is the original pump used on 165 L6 Mercruisers.