Motor runs to the filter bowl is empty then you have to keep pumping the bubble same old stuff everything has been changed carburetor has been rebuilt

[Robertabercrombie]

I've changed everything gas tank connectors on the tank hoses bubble clamps on hoses fuel filter and motor with new one hoses all the way to the carburetor everything's new from tank to the carb it will run into the bowl and the filter is empty then you have to keep pumping the bubble same old stuff and I don't know what to do I am just baffled and pretty upset I've been trying to get some of take me to the river for 2 years I bought a boat and still can't go because I can't get it running I need help please

 

[JUSTWANNARACE]

Type of motor would help. But it sounds like a fuel pump issue!

 

[Ultra...Good]

Yeah, fuel pump or an air leak in the line. I have had new primer bulbs that were no good. Found it by pulling a vacuum on the fuel line. Remember that the fuel line all the from the tank to the pump is under vacuum, not pressure. If fuel pump checks out remove line and pull vacuum. That is how I found the bad primer bulb.

 

[Flying_Lavey]

Rebuild the pump. Most of the mechanical pumps use a diaphragm to do the pumping that is susceptible to the ethanol in the modern fuels. It will eat pin holes in the diaphragm reducing the ability to pump fuel. Or...... put a high volume, low pressure pump on it and call it good (assuming you have a carbed engine)
.

 

[Todd Mohr]

Seen the same thing happen with a clogged vent line for the fuel tank.

 

[Robertabercrombie]

Type of motor would help. But it sounds like a fuel pump issue!

1999 Mercury 25EH everything had been replaced carburetor has been rebuilt New filter new lines new tank clamps on all lines new bubble everything except the plug that goes into the motor but I like the vacuum idea to check it from the carburetor all the way back I just got to figure out a way to pull in the vacuum on it I was wondering can you put a 3 to 5 lb PSI electric fuel pump on it but then I got to thinking when it's running sometimes it runs good but then sometimes I can hear a backfire a small pop I don't know if it's cuz I'm pumping too much gas with the bubble trying to keep it running or if something internally is going on I need some more suggestions please

 

[Justfishing]

Are you saying you get it pumped up. It runs and then dies. When it dies you then find the filter is empty.

I assume a mechanical fuel pump on the side of the engine. If it sucks the filter dry i say the pump is working.

I would look for an air leak.

 

[Ultra...Good]

1999 Mercury 25EH everything had been replaced carburetor has been rebuilt New filter new lines new tank clamps on all lines new bubble everything except the plug that goes into the motor but I like the vacuum idea to check it from the carburetor all the way back I just got to figure out a way to pull in the vacuum on it I was wondering can you put a 3 to 5 lb PSI electric fuel pump on it but then I got to thinking when it's running sometimes it runs good but then sometimes I can hear a backfire a small pop I don't know if it's cuz I'm pumping too much gas with the bubble trying to keep it running or if something internally is going on I need some more suggestions please

Vacuum test lines only from fuel tank to fuel pump. After pump lines are pressurized and leaks will not hide. Vac pump is cheap from auto part store, also known as a brake bleeder.

One other thing FWIW, fuel filter should be after the fuel pump. They are supposed to be pushed through, not drawn through.

 

[Robertabercrombie]

Rebuild the pump. Most of the mechanical pumps use a diaphragm to do the pumping that is susceptible to the ethanol in the modern fuels. It will eat pin holes in the diaphragm reducing the ability to pump fuel. Or...... put a high volume, low pressure pump on it and call it good (assuming you have a carbed engine)
.

 

[Robertabercrombie]

I ran it today and pumped it up full in the filter top of the motor The bowl in the filter was full I had to line loose from the tank cranked it up after I pressurized it and I put my finger over the end of the line while it was running it collapsed the bubble so that's telling me it's in the tank isn't it Even though it's new new bubble new lines new tank I guess it still could be bad but I really like the idea of a fuel pump electric if that will work on a switch would probably be cheaper than buying a new bubble and lines and tank thanks for the help I'm narrowing it down I think it's going to be the tank

 

[Robertabercrombie]

Are you saying you get it pumped up. It runs and then dies. When it dies you then find the filter is empty.

I assume a mechanical fuel pump on the side of the engine. If it sucks the filter dry i say the pump is working.

I would look for an air leak.

I'm thinking that now myself because when I have my finger over the line it goes into the tank ran the motor it sucked all the gas out and then sucked the primer up collapsed it stayed collapsed about an hour

 

[Robertabercrombie]

I'm thinking that now myself because when I have my finger over the line it goes into the tank ran the motor it sucked all the gas out and then sucked the primer up collapsed it stayed collapsed about an hour

But I am wondering is anybody ever put an electric fuel pump on one of these two to four lb of pressure is what a diesel fuel pump does I was wondering if that would work in place of the bubble

 

[Robertabercrombie]

But I am wondering is anybody ever put an electric fuel pump on one of these two to four lb of pressure is what a diesel fuel pump does I was wondering if that would work in place of the bubble

And it is a 1999 25 horsepower EH

 

[JUSTWANNARACE]

Is it a vacuum pump or mechanical pump?

If its vacuum did you replace line from motor to pump? Did you rebuild the pump? Replace the diaphragm?

Can you post a pic of pump and carbs?

 

[JUSTWANNARACE]

But I am wondering is anybody ever put an electric fuel pump on one of these two to four lb of pressure is what a diesel fuel pump does I was wondering if that would work in place of the bubble

It should have more than "the bubble" all the bubble is, is to prime the fuel pump and carbs. It does nothing after the motor is fired, at that point it should be the fuel pump supplying the fuel.

 

[Robertabercrombie]

It is a vacuum pump on a 1999 25 horsepower EH The only line to the carburetor is the gas line feeding it I guess it works off of suction through the reed valves I don't know that this is my first two-stroke outboard motor but I got to carburetor rebuild good I think it might be in the tank I held my finger over the line after I cranked it pull the line from tank it run all the gas out of the filter bowl then the pump bubble sucked collapsed and stayed that way about an hour so that's telling me it's got to be in the tank and it's brand new it throws me because I tried to open the top of the tank to see if the vent was not working properly but evidently it's the fittings I'm going to get on it in the morning I got a vacuum pump if I have to I can do that I appreciate all the help and the suggestions y'all have taught me a lot thank you very very very much I still wonder about that electric fuel pump deal because it would be cheaper to put an electric one on then to buy a new tank bubble and lines just can't get anyone to say they've seen it done before even if it's on a switch and fused

 

[Robertabercrombie]

I forgot to say when it pulled the bubble down and collapsed it I had my finger over the line that went in the gas tank and was trying to run the gas out of everything and I watched it suck the bubble down that told me it was vacuum to there because it stayed down when I took my finger off well about an hour

 

[JUSTWANNARACE]

I'm not saying that there isnt one but I have never seen a vacuum pump with only "fuel in and fuel out"? A vaccum pump should have a line, most likely off the cyl or intake(reed cage area), for pulse to the vacuum pump. So 3 lines minimum.

Can you post pics of the pump and carbs?

 

[HydroSkreamin]

That fuel pump is most likely bolted to the crankcase with a paper gasket in between.

As others have said, it could possibly be a bad primer bulb; I’m assuming this is what you’re calling “the bubble”?

Pump the primer to get pressure, have a double ended hose barb the size of your fuel line handy and remove the primer bulb from the system. If that doesn’t fix it, keep looking for leaks all the way to the tank, and as someone else mentioned, remove the fuel filter momentarily to see if it’s your leak.

You’ve determined that your pump works. Find out why your system isn’t putting out.

An electric fuel pump for a permanent solution seems like a good idea, but it isn’t. You’re trying to Band-Aid the problem instead of healing it. If the pump stays running, if you DO have a leak,you’ve got a serious problem on your hands. Also, it could possibly overcome the needle and seat, compounding your problem.

I’d suggest methodically eliminating system components; start with a hose directly from the fuel pump into a normal 2-gallon gas tank that you take to the gas station filled with clean gasoline. Just zip-tie the fuel line so it stays submerged and let it idle on the trailer. Once you determine it works, keep moving to the next break in the system until you find your problem. Remember, every connection and every component in the system is a potential problem. You’re trying to figure out which one isn’t doing its job.

You can do this, but you have to be methodical and you’re basically working your way down a problem solving flow chart.

Good luck!

 

[Robertabercrombie]

That fuel pump is most likely bolted to the crankcase with a paper gasket in between.

As others have said, it could possibly be a bad primer bulb; I’m assuming this is what you’re calling “the bubble”?

Pump the primer to get pressure, have a double ended hose barb the size of your fuel line handy and remove the primer bulb from the system. If that doesn’t fix it, keep looking for leaks all the way to the tank, and as someone else mentioned, remove the fuel filter momentarily to see if it’s your leak.

You’ve determined that your pump works. Find out why your system isn’t putting out.

An electric fuel pump for a permanent solution seems like a good idea, but it isn’t. You’re trying to Band-Aid the problem instead of healing it. If the pump stays running, if you DO have a leak,you’ve got a serious problem on your hands. Also, it could possibly overcome the needle and seat, compounding your problem.

I’d suggest methodically eliminating system components; start with a hose directly from the fuel pump into a normal 2-gallon gas tank that you take to the gas station filled with clean gasoline. Just zip-tie the fuel line so it stays submerged and let it idle on the trailer. Once you determine it works, keep moving to the next break in the system until you find your problem. Remember, every connection and every component in the system is a potential problem. You’re trying to figure out which one isn’t doing its job.

You can do this, but you have to be methodical and you’re basically working your way down a problem solving flow chart.

Good luck!

Thanks for the advice Y'all have helped me a great deal I replaced the pump bubble I did even try to put electric fuel pump on it would not stop pumping and I noticed after replacing all this and putting it back factory my new gas tank is leaking when it gets pressurized it swells up and at the top for the pickup is it leaks right there so it must be broke sucking air I've got a new tank ordered from Amazon should be here tomorrow Lord this thing has cost me some money rebuilt the carburetor it is a two-stroke now so that is the carburetor pump together replaced the filter twice two bubbles the pump ones in the lines together I think I had more than one problem because every time I find something I think I have it I find something else but the electric fuel pump was sucking up and pumping out bubbly air with the gas so I new then it was sucking air between the pump and the tank so I took it back out of the equation and put a new pump bubble in just waiting on my tank now Hope that will fix it it's amazing what a little Walmart thing can do it's about drove me crazy but I appreciate all of the help I really think I've got it because I was hand working the throttle it runs too good I can rev it up sitting there with the hose pipe on it and it runs good until I quit pumping that bubble but it will crank right back up once you pull the choke twice pump it twice and let it crank push it in it'll run until it all sucks out of the filter but I think the tank will get it thanks for all y'all's help if it don't I will come back and ask some more and show some pictures

 

[Robertabercrombie]

I'm not saying that there isnt one but I have never seen a vacuum pump with only "fuel in and fuel out"? A vaccum pump should have a line, most likely off the cyl or intake(reed cage area), for pulse to the vacuum pump. So 3 lines minimum.

Can you post pics of the pump and carbs?

So you saying those two lines coming from the below the head area one from each cylinder they come around behind the linkages to the reed block under the carburetor they have check valves on them by the diagram I've been wondering is that how it gets it suction but it revs up and runs great until the filter bowl runs out but it is above the carburetor gravity could be doing that The pump in the two-stroke carburetor works because when it dies I have to pull it twice to pump twice and it fires straight back up until the bowl runs out unless I pump the bubble by hand by the tank but then two little lines from the front even if the reeds are working they could be stopped up that's my next place to look I guess all they could have a hole on them you really can't get to them without taking all of the linkages off thanks for the help I've been wondering what them lines did

 

[Robertabercrombie]

That fuel pump is most likely bolted to the crankcase with a paper gasket in between.

As others have said, it could possibly be a bad primer bulb; I’m assuming this is what you’re calling “the bubble”?

Pump the primer to get pressure, have a double ended hose barb the size of your fuel line handy and remove the primer bulb from the system. If that doesn’t fix it, keep looking for leaks all the way to the tank, and as someone else mentioned, remove the fuel filter momentarily to see if it’s your leak.

You’ve determined that your pump works. Find out why your system isn’t putting out.

An electric fuel pump for a permanent solution seems like a good idea, but it isn’t. You’re trying to Band-Aid the problem instead of healing it. If the pump stays running, if you DO have a leak,you’ve got a serious problem on your hands. Also, it could possibly overcome the needle and seat, compounding your problem.

I’d suggest methodically eliminating system components; start with a hose directly from the fuel pump into a normal 2-gallon gas tank that you take to the gas station filled with clean gasoline. Just zip-tie the fuel line so it stays submerged and let it idle on the trailer. Once you determine it works, keep moving to the next break in the system until you find your problem. Remember, every connection and every component in the system is a potential problem. You’re trying to figure out which one isn’t doing its job.

You can do this, but you have to be methodical and you’re basically working your way down a problem solving flow chart.

Good luck!

I have replaced everything except the connector at the motor and I bypassed it I'm going to try one more time before I pull the carburetor off to go straight to the carburetor with the inline new filter vine bubble tank and all if that don't work it's got to be the vacuum from the motor and that we're talking about a two-stroke here 99 model 25 horsepower EH electric start tiller handle there are two lines coming from the head one from each cylinder they go into for the reed block is under the carburetor where the carburetor mounts to the reblock these hoses go under it into the reed block The diagram says they are check valves on the end of them I'm guessing that's got to be where it gets its pulse to suck gas or suck the diaphragm in and then the spring pushes it back out to pump I'm not a mechanically engineere but I know a little something I've worked on central air conditioners and with electrician for 15 years in the mills around here cotton mills just looking at the diagram I'm wondering how I can check the suction on these lines should I be able to fill it if I just unplug them and pull the handle the cord to start with the plugs in but unplugged where it cannot crank should I fill a vacuum if I don't that means serious serious serious problems Head gasket or upper lower main bearing just from what I've been seeing on these YouTube videos some okay some should not even be on there I was just wondering though to shorten this up sorry to go along so long but should I fill a vacuum or is there another way I need to put the motor in a certain place like piston down piston up and put 5 lb of pressure on it no more than five should I get it to hold pressure I'm just wondering what's the best way to take this any help any would be very much appreciated

 

[King P.V.]

Yeah, fuel pump or an air leak in the line. I have had new primer bulbs that were no good. Found it by pulling a vacuum on the fuel line. Remember that the fuel line all the from the tank to the pump is under vacuum, not pressure. If fuel pump checks out remove line and pull vacuum. That is how I found the bad primer bulb.

Remember, when checking vacuum readings.... you need a slight amount ( 1 or 2 inches of draw) when everything is working correctly. That's the fuel pump drawing/sucking fuel. To have no vacuum at all, means there's a an air leak or a non-operating pump . That's why you use a vacuum guage with a clear line to observe for air bubbles. No air and 1 or 2 " of mercury on guage.You don't want more than that on the vacuum side which would indicate restrictions. On the pressure side of the mechanical pump, ...no air and around 7 psi or do on mechanical pump. If using an electric pump you need to regulate it . Too much pressure and you'll compromise the carb needles. Additionally. Check all connections for integrity. Hoses need to be in good shape, clamps need to be tight. Minimize the number of step-downs/ connections . Less is always better. And if you have the quick release fittings on your oil tank OR on the engine pan for fuel, get rid if them .

 

[King P.V.]

Remember, when checking vacuum readings.... you need a slight amount ( 1 or 2 inches of draw) when everything is working correctly. That's the fuel pump drawing/sucking fuel. To have no vacuum at all, means there's a an air leak or a non-operating pump . That's why you use a vacuum guage with a clear line to observe for air bubbles. No air and 1 or 2 " of mercury on guage.You don't want more than that on the vacuum side which would indicate restrictions. On the pressure side of the mechanical pump, ...no air and around 7 psi or do on mechanical pump. If using an electric pump you need to regulate it . Too much pressure and you'll compromise the carb needles. Additionally. Check all connections for integrity. Hoses need to be in good shape, clamps need to be tight. Minimize the number of step-downs/ connections . Less is always better. And if you have the quick release fittings on your oil tank OR on the engine pan for fuel, get rid if them .

Additionally, I was actually talking about bigger engines ,V6's, as to removing quick-connect fittings but troubleshooting pressures, vacuum reading and clear lines holds true for all engines . Johnson/Evinrude service manuals cover this troubleshooting in pre-Ficht and ETec books . I thinklater Merc ones do too. But...2 strokes don't like air, restrictions or ethonal. Or too much prop. Use QuicKare and QuicKleen. Read the labels please.

 

[HST4ME]

The Reed blocks on those motors are rubber coated, the rubber surface deforms and there goes the reed seal..there goes the crankcase pressure and there goes the ability to pump fuel.