140 hp Mariner can't get fuel

[Gman4296]

I have a 1979 Mariner 140 hp outboard. The engine starts and runs strong - but here's the problem - Intermittently the engines stalls because it is not getting fuel. You can see the primer bulb go flat as the engine is not able to pull fuel into it.

You can sometimes keep it going by manually massaging the primer bulb to inflate w/gas - but having someone sit in the back of the boat and fondle the bulb is no way to go through life - and it's not guaranteed to work since sometimes you just can't get the bulb to fill again until you shut the engine down for a short time.

Here's a rundown of what I've done so far:

- When this first happened we though it was the fuel pump - so we rebuilt it - result - no change

- Next we hunted down and replaced the fuel lines and the fuel filter/water separator - even digging into the tank to replace the line that sits in the tank
result - no change

- Next I went out and bought a new 6 gallon external tank and hooked it up to bypass the internal tank.
result - things went well - for about 15 minutes - then the same thing started happening again.

Does anyone have any ideas on what could be choking off the fuel supply? Could it be the carburators? I'm at a loss since everything runs smoothly aside from the lack of fuel delivery.

Any help is appreciated.

Thanks -

Gary

 

[Barnacle_Bill]

Re: 140 hp Mariner can't get fuel

When you used the external tank did you use a different hose?

 

[jebeebe]

Re: 140 hp Mariner can't get fuel

The problem has to be between the fuel bulb and the tank or it wouldn't suck the primer bulb flat. Some where between the bulb and the tank there is obstruction. Or the vent isn't working.................Jerry

 

[Silvertip]

Re: 140 hp Mariner can't get fuel

The bulb itself can have a sticking check valve. If it does the same thing on a new tank, check the length of hose from the tank to the bulb for obstruction. If it's clear, replace the bulb.

 

[Gman4296]

Re: 140 hp Mariner can't get fuel

Everything from the tank out is new. I bought the new tank along with new fuel lines and a new primer bulb. I've even tried by-passing the fuel/water seperator filter - all w/the same results.

 

[Silvertip]

Re: 140 hp Mariner can't get fuel

This is pretty remote, but I have seen plastic debris (small bits of plastic) from the tank manufacturing process inside many new tanks. These bits can work their way into the bulb plugging it up. I speak from personal experience. It may be that you got one of those tanks and the new bulb or the tank pickup is plugged. Primer bulbs cannot be sucked flat due a problem between it and the engine. It can only be sucked flat if one of the check valves is bad or there is a restriction between the bulb and the bottom of the tank. Is the portable tank vented properly. If not, air can't get in and fuel can't get out. If the main tank has an anti-siphon valve, it could be stuck. Same for the portable tank. The anti-siphon valve is the barb fitting the fuel hose is attached to. It has a spring loaded ball inside it and they have been known to stick.

 

[Gman4296]

Re: 140 hp Mariner can't get fuel

I'll check the valves - Thanks!

 

[ncroger]

Re: 140 hp Mariner can't get fuel

I am having this same problem. Were you able to solve your problem?

 

[zapped77]

Re: 140 hp Mariner can't get fuel

Gman 4296

I just answered ncroger on the same issue. I was have the same problem for the last week and now it is running like a champ.

I just had a problem with my merc 45hp outboard and it sound the just like the problem you are having I changed fuel lines, rebuilt carb and checked tanks and the motor would not run correctly and today it came to me check the float in the carbs.

That was the problem the floats were not letting enough fuel in to the carbs so the motor would run for a few minutes the start cutting out due to lack of fuel the fuel line bulb would be soft.

If you pump the bulb slightly will it keep running? I would check the floats levels if you have a repair manual it should show instructions.

good luck

 

[ncroger]

Re: 140 hp Mariner can't get fuel

thanks, that sounds like a good idea. I will check tomorrow.

 

[cougar1985]

Re: 140 hp Mariner can't get fuel

went through this exact same problem yesterday on my motor,which is a 1982 evinrude 90 hp.when all is said and done it was the bran new hose and bulb which got stuck somehow.i replaced it and the motor runs like a champ.a easy check is to disconnect your fuel line somewheres foward of the bulb and line ,i did it right at the fuel pump then i squeezed the bulb ,no fuel or weak spurt ,faulty bulb its that simple.hope this helps.sometimes those checkvalves get stuck one way for no apparent reason but once unstuck should be ok .

 

[Gman4296]

Re: 140 hp Mariner can't get fuel

Hey guys - I fixed my problem - for the most part. The rubber gasket in the vent cap was folded over and therefore wasn't venting the new external gas tank I put on. I cleared the vent and she ran like a champ all weekend.

I still haven't addressed the internal tank issues yet. My guess is that there is something clogging the vent to the tank as well.

It's kind of a pain having to keep the 6 gallon tank constantly filled but at least the boat is running solid - so that's a pain I can live with until I get the time to monkey with the bigger tank.

Thanks for all your help - hope you can get yours running as well.

G