Fuel delivery problem

[Taterman]

Hi folks, I'm working on a 2002 Mercury outboard motor on my Bass tracker boat. The boat had been previously neglected for about 4-5 years. The following work has been done to the motor: Carburetor has been removed, cleaned and new kit installed. Dumped all fuel from tank , mopped out dry and added new 93 octane gas with a can of sea foam .Sea foamed carburetor twice. Motor starts but dies out. Replaced all fuel lines and clamps Replaced fuel line and primer bulb assembly(Attwood). Same problem. Hooked up external tank with Quick Silver primer bulb and hoses and motor runs. Returned Attwood fuel line kit , purchased and installed new Mercury Quick Silver fuel line kit. Same old problem- motor runs but loses prime. I have also put a new fuel intake line into the tank(in which I cut it about a 1/4 " shorter than the old one to make sure it's not pulling on the bottom of the tank). We did take the boat out on the river and give it a good run. It runs pretty good under load but has the persistent low idle dying out problem. I would appreciate any help in this matter as I don't have much hair left to pull out.

 

[carholme]

Re: Fuel delivery problem

You don't say what engine it is. Do you have the hp and s/n?

Gerry

 

[CharlieB]

Re: Fuel delivery problem

Carb linkage sync, idle mixture are critical to idle quality, ignition timing is set while cranking on the starter but final idle speed is adjusted with the idle timing stop screw.

A factory service manual spells these steps out in detail, aftermarket manuals not near as well.

Post you motor model and serial and someone will tell you exactly which Merc Manual you need.

 

[Taterman]

Re: Fuel delivery problem

The motor is a 25 HP. Tracker 25 Pro Series Model 1025312ZN Serial# OT419540

 

[carholme]

Re: Fuel delivery problem

The manual you require is P/N: 90-826883

If you do not have this manual, see my message to you in Notifications at the top of this page.

Gerry

 

[MH Hawker]

Re: Fuel delivery problem

If i understand correctly in a portable tank it runs fine and on the main tank you have problems. Do you have any of the silver fuel line in the system, if so I would bet that is the problem.

 

[Taterman]

Re: Fuel delivery problem

I have the silver line on the portable and the fixed tank. In between raindrops I went out and blew air thru the fitting on the back of the boat that connects the fuel line to the tank and the primer bulb hose assembly. No blockage there. I'm going to have to wait until tomorrow to do anything else on account of bad weather.

 

[1FASTLASER]

Re: Fuel delivery problem

Be sure to check tank vent. Them smaller motors need good venting throughout the tank because the pump is not real strong. If the vent is somewhat restricted it will as you say it is doing. Boat tank no run...portable tank run. See what I mean

 

[MH Hawker]

Re: Fuel delivery problem

The silver line has a inner liner that breaks lose and wads up and blocks the fuel flow.

 

[Joel K]

Re: Fuel delivery problem

The silver line has a inner liner that breaks lose and wads up and blocks the fuel flow.

Questions for anyone on the Silver colored fuel line inbetween the tank and motor.
I have a 1994 Mercury 40HP. I pumped the ball today before hooking it up to the motor, and fuel came out when the valve shouldn't have allowed it. I saw what looked like a small piece of clear rubber in the valve that was keeping it open.
I opened the valve with a pick and caught several pieces in a jar mixed with the fuel.

I assume the inner lining of that Silver fuel line is coming apart.

If I'm right, what would you recommend I replace that line with?

What's the chance it has already found it's way into the fuel pump?

Any reason why I couldn't install a fuel filter before the fuel pump, instead of after the pump and before the carbs like the original
set-up?

Thank you!

 

[Texasmark]

Re: Fuel delivery problem

The gray silicon (looking) OEM fuel line failed on me too after 10 years. I had the little flakes in the entire fuel system; the ones that made it through the bulb and didn't get jammed up there.

You may need a new fuel pump/clean out the pump parts and surely fuel filter in the engine....I guess you have an internal filter, I have one in my 90.

Posts on here suggest using the Quicksilver squeeze bulb so I did so and the fuel line was purchased at an auto parts store and was said to be ethanol compatible.

Just because you see a vent is no proof it's venting. Blow through it to ensure it is.

After sitting 5 years the inlet screen in the tank may be varnished over....assume there is one, mine has one.

I too am a Sea Foam user and convinced as to it's functionality.

HTH,
Mark

 

[Taterman]

Re: Fuel delivery problem

After replacing everything in the fuel system and still having problems, I had to back track all that was done. On my boat there's a fitting on the bulkhead where the hose from the fuel tank connects on the bottom and the primer bulb assembly hose hooks up on top.I took the hose lose up top and ran a Phillips screwdriver down thru it to make sure I had a clean passage. I believe there was a partial blockage in the fitting that was causing me all the grief. After that ,I was on the right track and a friend of mine and I river tested the boat last weekend and did some fine tuning on the RPMS and air/fuel screw. I'm no expert but I would just slowly go over one piece at a time. If the fuel line is deteriorating, replace it.

 

[Joel K]

Re: Fuel delivery problem

Thanks for both of your replies!

TEXASMARK: You said you replaced your line with what I assume is black fuel line for auto's which is what I was considering so I could get a longer length and place the bulb in a part of the line where it could be hung in the upright and proper position. Would you happen to remember the size of the fuel line? I'd probably take the line off and bring it with me, but I wasn't thinking of cutting the ends off until necessary. My primer bulb is only one or two years old and seems to still be fine.
My fuel tank is permenant and hard to get to, so I'm not sure if I want to pull the fitting just to check the screen, but I might see if I can shoot some air through the line to the vent to make sure it's open.

 

[Texasmark]

Re: Fuel delivery problem

5/16 is plenty for your engine. Mine requires a 3/8. Fittings on OEM bulbs will adapt to either. If you can't find a 5/16 go ahead and get a 3/8. No biggie. You can put the bulb anywhere along the line. Usually it is close to the engine for convenience. Pay attention to the arrow on the bulb and point it in the direction of fuel flow.

Mark