Having problems with 15 hp 1996 mariner not pulling any fuel?

[jldean23]

when i got motor it died and i thought bad gas or something, well seems to not be the case. This is a 1996 15 hp mariner with a WMC series carburetor with a integral fuel pump. I have been De-carbonizing motor and kept noticing after a bit it would die out because of no fuel, pumped primer bulb and it was good to go gets hard then again i can see that fuel filter gets lower and lower but as if the motor will not pull more fuel. now when i was decarbonizing and had throttle up seemed fine but at idle it acts like fuel pump just isnt pulling hard enough, well looked in service manual and it has no external fuel pump it is inside the carb. Before i new this and when i looked at it when i bought it did this also but i just thought it was were it sat awhile bad fuel etc...When i tilted it up i seen it leaked fuel a bit not dripping but could smell fuel so i ordered carb re-build kit, here is a link to show my carb maybe my carb is the one in the manual lol who knows..

http://mercuryperformance.com/produ...arburetor Assembly (0G760300).jpg&w=600&h=579

I have no idea why it is not pulling fuel, there is a extra diaphragm that came in kit i dont know if it needs the extra one or??? i went by what was on it before and bye my service manual but it does say can be different from pics in manual. here is the one in the manual..



The first pic is a different one i found. Maybe it doesnt need gasket #13 in the service manual pic i dont know the internal fuel pump is #25 maybe the diaphragm has to be on the pump without gasket #13 and only diaphragm #56 but the extra diaphragm that is not in the manual might go on it?????



the one on left is the old one that came off carb and the one on the right is the one that is not in any of the diagrams but the holes line up????? hope you guys can help thanks sorry so long but had to explain right to give you guys all the info.....

 

[CharlieB]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Both are needed. The gasket on the left is the actual pump, the one on the right is the 'check valves'. Without the check valves in correctly the pump with simply pulses fuel back and forth, NOT moving fuel to the carb.

Is that a FACTORY manual?

You might find a better parts view and description of every part at Merc parts. Have your model and serial #'s handy

The #1 web site for genuine Mercury Mercruiser engines, parts and propellers

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

So basically my diagrams are showing most carbs with a external fuel pump and that is why it doesnt show the extra diaphragm in the pics?? Since mine is a internal fuel pump it needs it? Now only thing that makes since is this guy got it serviced last year he put on a new coil pack and said he checked the carb and it didnt need a rebuild kit, but it was leaking when i got it and maybe he lost or forgot to put that part on i dont know. i went to that site and it still shows the same pics the other do and no it is a aftermarket manual a Clymer.
So the solid diaphragm goes toward the cover and the one you called the check valve diaphragm with the flappers on it goes closest to the carb? there was a extra regular gasket as well, but do i use no regular gaskets with the rubber diaphragms or does the diaphragms go against the fuel pump body with no regular gaskets or one on outside of each diaphram with a total of 4 gaskets total on just the fuel pump which would be 2 rubber against body and 2 paper gaskets on the outside of them? Thanks this was real confusing i was trying to go bye the book and as you are saying lol you cant always go by the book let me know thanks..

 

[CharlieB]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

The FACTORY Manual will show exactly what gaskets go where.

Often the diaphragm will have an 'outline' gasket on one side so as to provide enough room for the pump diaphragm to move fully.

The check valve installs such that one of the 'flappers' seals against a passage (hole) on one side while the other flappers seals against a hole on the other side of the gasket.

Like I said, the factory manual clearly shows all. Without actually seeing all the parts it is very hard to tell you on here exactly where each gasket goes.

If someone has been into this and left any part(s) out it will be very difficult to straighten out without help or the Factory Manual.

Send me a PM with a good email addy and I can send you a copy of a manual that might clear this up.

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Ok took carb back off and put the 2 diaphrams on either side of fuel pump i have pics to show what manual shows and i put it on like you were saying here is a pic of the fuel pump area..


here is the fuel pump pics


Ok last pic is carb put together i think it is right i forgot to put pic of diaphram with the check valve flappers thanks

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Ok i called mercury and talked to a technichian he said i do not need that extra diaphram to use the last carb pic use that diaghram you sent me but he did say i didnt need that paper gasket on the diaphram side. So what else could it be??? I am going to check the float but other than that what could it possibly be.

Too cold i cant run it till it gets a lil warmer ill put it together like the merc manual says which it is diffrent from the way i took it off i dont see how just a paper gasket would make that much of a differenc e but we will see thanks let me know guys...

 

[MH Hawker]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Take a close look at the fuel line fittings, if a O ring is bad it will suck air and not gas that is a common problem.

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

the only line is the one on top of the carb are you talking about the lines from the fuel tank, to the fuel filter, then to the carb??? there is also a line that goes onto the bottom of the carb but i think it might be a vacuum line..

 

[MH Hawker]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

I was talking about the ones going from the motor to a remote tank if you have one. Especially if you have the silver fuel line it has a clear liner that goes bad and clogs things up

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

I have a new hose and bulb from tank to motor so all that would be left is the fuel connector on the motor, then the fuel filter area. I just looked, the line on the bottom is fuel going to engine it has the check valves on the block one on top and one on the bottom, i mean surely they are not messed up or stuck cause if that was the case no fuel would get to motor at all..

 

[MH Hawker]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

I am using the same motor on my pontoon boat by the way.

Those are the fitting I am talking about, They have O rings to seal them off while in use, over time they wear and harden, and when the motor is running it sucks air instead of gas, the motor end ones on the hose end or on the motor itself often fail and cause just the problem your having. I have replaced them many times to solve that problem, normally it is the hose end one. It may not be the problem, just some thing to look at.

Last year I had the same problem and it turned out to be the silver fuel line, That stuff has a clear inner liner and that had collapsed and was blocking the fuel flow.

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Cheap part if this is it here is a link to the fuel filter assembly so that we are on the same page..


FUEL FILTER ASSEMBLY FOR MARINER / MERCURY 6 / 8 HP 9.9 / 15 HP

So you think it is #8, #10, or #4 or guts inside #8

I put the carb back the way mercury said so hopefully that will solve that issue if that is it, i looked maybe it is leaking like you say there is dirt around #8 on plastic below on motor looks to much for just usual taking plug off at end of day use from tank. And thanks for chimming in that is great that someone has the same motor and had the same issue, so how did yours occur was you at low speed like trolling and it just died out or??? like i sad when at 1/4 throttle it seemed to not run out of fuel because i was decarbonizing BUT when i let it idle to clear all the smoke i could see fuel get lower and lower then it would die i would primer bulb it again and it was fine.

And this same thing happened to you 3 times and what exact part did you change and thanks for the help...

 

[MH Hawker]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Item 8 is the motor end and its rare that's the problem, but the line fitting that connects to it is often it. This has O rings inside to seal it off so no fuel leaks out, but it can wear just enough to allow air in. Most fuel lines have one at the motor and one at the tank if your using portable tanks.

It would run out of fuel about 1/2 throttle and stall, but would start fine after a bulb pump, I had heard that the silver fuel line was crap so I picked up some new marine grade line at a local shop and replaced that and it fixed it and while changing it out I found a good amount of the liner wadded up at the motor end fitting.

the line fitting


bad fuel line

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Ohh k i see yea the guy gave me one with motor and a tank the tank has just a older style quick connect like on a air tool i havent even used it yet i just had the hose sticking in a 2 1/2 gallon gas can for decarb process. I will go buy i new connection tonight just to rule that out and i see you are in Wv and lol ill have to wait till it warms up or at least sat to test this all out.

And the fuel line is brand new it looked good to me i think this one is rubber on inside then a grey outer coating. Hopefully it will be fixed we will see thanks ill report in when i run it next...thanks again..

 

[jldean23]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

well i got my boat yesterday older lowe 1448, and i put gasket like mercury said with only the 1 diaphram and i put on a new gas fitting for the fuel hookup. So i took it out and no problems it pulled its own fuel lol only thing i dont know is which part i fixed, it ran really good i am pleased it is working well thanks for allthe help guys....

 

[MH Hawker]

Re: Having problems with 15 hp 1996 mariner not pulling any fuel?

Thats one of those things, it dosnt matter what it was , its fixed , go and enjoy it. The fitting are a very common and over looked problem.