Doing tune up, pretty sure my fuel pump is bad but i have a question.

[chistedude]

Hey everybody
Kinda a newbie here, but I've been coming here for answers for quite some time. This is the third season I've had my 01 bayliner with a 3.0 mercruiser. Decided to give it a good overhaul before the season, rebuilt the card, replaced spark plugs distributor cap and rotor. Went to change the oil but the drain plug was completely corroded so I had to drop the oil pan, oh ya big mess by the way. So I get everything back together and go to start er up but no fire. Through a little investigation I realize I'm not getting fuel, I took the fuel line off the Carb turn it over a few times, no fuel. Come to find out I knocked my fuel filter off when removing my oil pan. Went and bought a new filter while I was at it, get that put on try to turn it over a few good many times, still no fuel spitting out. My fuel pump was working as of last July, and I've heard those mechanical pump are pretty solid. So I put some gas in a bowl as a remote fuel tank and put the line into it to see if it'd suck it up but no luck. So now the only thing I can assume is the pump went bad. Do pumps usually go bad like that by sitting? I know its a 12 yr old pump so I don't have a problem replacing it, I just can't believe it'd just go out. But ya, anyways, my question after making y'all read all of that is this. As I was trying to figure this all out I happened to blow air into the line going into the pump from the tank. The air makes it all the way to the end with the Carb and I hear a slight buzzing vibration noise coming from the fuel pump. Would this be normal? (not saying its normal to blow air into the pump) but would the air normally be able to make it past the pump or is that a good indication that the pump is bad?
Thanks for listening, feel free to chime in if u have any thoughts on the matter.

 

[HT32BSX115]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

So I put some gas in a bowl as a remote fuel tank and put the line into it to see if it'd suck it up but no luck.

So now the only thing I can assume is the pump went bad. Do pumps usually go bad like that by sitting? I know its a 12 yr old pump so I don't have a problem replacing it, I just can't believe it'd just go out.

But ya, anyways, my question after making y'all read all of that is this. As I was trying to figure this all out I happened to blow air into the line going into the pump from the tank.

The air makes it all the way to the end with the Carb and I hear a slight buzzing vibration noise coming from the fuel pump.

Would this be normal? (not saying its normal to blow air into the pump) but would the air normally be able to make it past the pump or is that a good indication that the pump is bad?
Thanks for listening, feel free to chime in if u have any thoughts on the matter.

Howdy,

Welcome Aboard!


While you're checking, check the anti-siphon valve at the tank and the tank vent tube.

The "buzzing" is probably a check valve inside teh pump.

Yes. It's not all that unlikely that the pump has failed from old gas sitting inside.....but it might just be a stuck check valve. problem is that if you take it apart, it might start leaking. The older pumps have the check valves crimped into the pump body casting and are not really serviceable.

If it definitely is not working, (and you have ruled out clogged fuel lines) replace it and the (flexible marine-type) fuel hose from the tank to the filter.

Regards,


Rick

 

[HT32BSX115]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

...

 

[tazrig]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Fuel pumps will go bad from old gas. It turns to a cottage cheese like consistency and clogs it right up. Time to replace it.

 

[bonzoscott]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Easy way around your oil change - they make both electric and hand pumps where you simply slip a hose down the dip stick opening and pump the oil out. The electric type is 12 volt and hooks to your battery and takes mine about 3-4 minutes.

 

[stoneSWH]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Easy way around your oil change - they make both electric and hand pumps where you simply slip a hose down the dip stick opening and pump the oil out. The electric type is 12 volt and hooks to your battery and takes mine about 3-4 minutes.

I even use the hand pump on my cars. My BMW oil filter is accessed from the top, so I never even have to get under the car to change the oil. My boat's 2006 Vortec came with an oil pan extender hose, but I didn't bother to use it because the hand pump method works so well.

 

[wrench 3]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Just make sure you get a marine fuel pump. The automotive ones look the same but they will spray fuel all over the engine compartment if they fail. Could get noisy. (and hot)!

 

[chistedude]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Howdy,

Welcome Aboard!


While you're checking, check the anti-siphon valve at the tank and the tank vent tube.

The "buzzing" is probably a check valve inside teh pump.

Yes. It's not all that unlikely that the pump has failed from old gas sitting inside.....but it might just be a stuck check valve. problem is that if you take it apart, it might start leaking. The older pumps have the check valves crimped into the pump body casting and are not really serviceable.

If it definitely is not working, (and you have ruled out clogged fuel lines) replace it and the (flexible marine-type) fuel hose from the tank to the filter.

Regards,


Rick

Hey Rick,
Sorry for the delayed response. Good info. I just ordered a new pump today. I think I'm goin to take advantage of the bad on and open er up, learn what makes it tick lol.

And thank you everyone else whom replied.

Anyone got a good way to do away with all my old gas siting in the tank?

 

[HT32BSX115]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Hey Rick,
Sorry for the delayed response. Good info. I just ordered a new pump today. I think I'm going to take advantage of the bad on and open er up, learn what makes it tick lol.

And thank you everyone else whom replied.

Anyone got a good way to do away with all my old gas siting in the tank?

That will depend on how long it's been in there.

You can certainly use it (within reason) but the length of time it's been in there will determine how much fresh gasoline you should mix with it. I have run 5 year old gasoline in my car mixing it 2 gallons(old) to 10 gallons(new).....and, every year, I run my boat to about 1/4--1/2 tank in the Fall and refill it in Spring/Summer.

Since you don't know if the tank is contaminated (water/debris) or the fuel pick up screen is clogged, Go to a marine supply store and get yourself a new fuel gage sender gasket kit (gasket and screws...a couple of bux)

Then remove your gage sender in the tank and use that hole to insert a clear vinyl hose and siphon all the old gas out into a suitable container(s)

If the sender mounting hole is near the back of the tank, you can tip the bow up so any water or sediment in the tank will run back towards the hole.

Use a piece of hose that is long enough so you can see the gas coming when you start the siphon. (mine is about 20ft long. got it from Home Depot along with some PVC pipe and a 1/2" ball valve)

Incidentally, you DO NOT have to use your mouth to start a siphon! just connect a small (1/2") ball valve on the other end of the hose, fill the hose with fuel and then close the valve. It sometimes helps to have a piece of plastic pipe on the end you'll put in the gage sender hole............ put that end into the tank and have a helper put the other end into the fuel receptacle you're using to drain it into.

If you have the boat on a trailer, and you're on a sort of a hill side etc, using an even longer hose increases the suction of the siphon the lower below the boat you get ......(head-pressure and suction vacuum are increased the higher the siphon is above the tank you're draining into! [Physics 101!!])




Use the end with the plastic pipe to move around in the tank like a vacuum. It will suck out ALL the water and small debris in the tank. When the container is full, your helper closes the valve (maintaining the siphon) and gets another one.

DO THIS OUTSIDE! in the "open" ....NO Smoking! & have a fire extinguisher ready!

I did the above on a 1987 boat I bought from my brother in 2005. I thought the tank was "dirty" inside from nearly 20 years of use.
I drained approx 25 gallons of 2+ year old gasoline from the tank using the above process. (I ran all of it in my car diluting it half & half) to my surprise, there was NOTHING in the tank.....no water or "debris". I also removed the fuel pick-up tube with the screen on the end and and it was clean.

The fuel pick-up tube usually also has an anti-siphon check valve with it. If yours is questionable, they're not that expensive to buy.

Here's one right here on iBoats: Moeller Aluminum Anti-Siphon Valve - iboats

Anti-Siphon Valve, 3/8" Barb, 3/8 NPT - Moeller

Part # 033802-10
3/8", 3/8 NPT, Aluminum Anti-Siphon Valve

• Delivers Coast Guard/industry standard anti-siphon protection on all gasoline-powered boats.
• Conbines anti-siphon protection with a convenient hose barb design.
• Made of tough aluminum.
• Features 1/4 NPT threads.

Product # 033802-10

Cheers,

Rick

 

[WSKIPPER]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Did you have the pump off with the pan removal?...if so you may have it under the cam lobe with reinstall or if it has a pushrod it may have fell down when removed...you can manually push the lever with the pickup hose in a small container of fuel and check it's operation....I read that here some time ago and can't remember where...you should angle the pump up when installing and feel the tension of the lever when installing...look closely...they are pretty reliable and simple pumps...

 

[ktbarrentine]

Re: Doing tune up, pretty sure my fuel pump is bad but i have a question.

Hey Rick,
Sorry for the delayed response. Good info. I just ordered a new pump today. I think I'm goin to take advantage of the bad on and open er up, learn what makes it tick lol.

And thank you everyone else whom replied.

Anyone got a good way to do away with all my old gas siting in the tank?

Ahh.. a man after my own heart! I once did the "autopsy" on my old fuel pump and learned alot (of course you can probably see it all, learn it all on youtube! What a world we live in now!!!). I have also been told that the diaphram does not like ethanol in the newer fuel mixtures. Check out your diaphram when you pull the pump apart. Mine was 20+ years old and sure was worn out and cracked bad. Also had problems with a new aftermarket fuel pump that failed after only 7.5 engine hours (the joint where the diaphram met the actuator rod failed). OEM pump is running great for many hours now.