Hi folks, hoping someone here can help me with a fuel delivery issue I’ve been having and can’t seem to solve. I’m not much of an engine/mechanic guy, so apologies for maybe not calling parts by their right names.
I’m looking for ideas on what else I can check or what the issue might be. Including all the long-winded details below.
Engine info: 2002 Mercury Outboard 25hp, 2 stroke, Model 1025201ZD
Fuel pump: on this engine it is an integrated part of the carburetor assembly, attached to the side of it. So not a separate stand-alone pump assembly.
Issue: My motor won’t stay running unless I continuously pump the fuel bulb. If I don’t pump it, the motor runs out of gas and dies. Seems to start and run OK as long as I can manually pump the gas bulb.
Background and what I have checked and done so far:
• Early summer, after the engine sat over winter it wouldn’t start, I saw that the gas had crystallized inside of all the fuel lines and fuel filter area. From gas tank all the way up through the filter area.
• I replaced the entire gas line and bulb from the gas tank to where it plugged into the engine. It was an after-market line assembly.
• I then took the motor in to get it serviced at a boat shop. The rebuilt the carburetor, tuned it, replaced plugs, replaced the two fuel lines inside the engine (the one running from the entry valve to fuel filter and the other line that goes to the fuel filter into the fuel pump).
• My boat then sat in the driveway (I never ran it after getting back from the mechanic) until this fall when I took it out and my engine would not stay running unless I pumped the gas bulb.
• I then replaced the after-market gas bulb I previously installed, with a new with an OEM bulb, thinking the after-market one was defective.
• I then thought maybe it was the fuel pump and was not sure they rebuilt it when they were servicing it. So I replace the gasket and diaphragm in the fuel pump myself. I did not replace the pump body which is a plastic part with the two valve flaps and spring. They seemed to work OK and moved freely.
• I checked for vacuum/pressure leaks and could not detect any inside from the fuel filter down to the entry connection. From the bulb into the engine valve/connection seems air tight also.
• Gas flows pretty freely when bulb is pumped into the filter assembly, so does not seem blocked or restricted. Also checked the two fuel lines inside engine to be sure and those are clear.
• Here is one possibility where I detected a vacuum issue - I pulled the siphon hose assembly that is down in the gas tank. When I press the gas bulb I can hear a very slight leak somewhere on the fuel gauge or where the hose attaches to the nipple on it. Tightening the hose clamp does not fix it. It is extremely (very) small hiss, but seems way too small to cause no fuel to flow. I have to squeeze the bulb pretty hard to make it do it also..normal pressure doesn't seem to be enough to make it hiss. Would a pin prick leak stop the fuel delivery? My gut tells me it is way to small to be the issue and that I have to press so hard to get it to do it. I may be completely wrong though.
At this point, I feel I’m throwing money at it hoping something works, so before I buy a new gas tank I don’t need, any ideas on other things to check or potential problems? Maybe the mechanic didn’t rebuild properly and missed something?
Thanks for any help.
I’m looking for ideas on what else I can check or what the issue might be. Including all the long-winded details below.
Engine info: 2002 Mercury Outboard 25hp, 2 stroke, Model 1025201ZD
Fuel pump: on this engine it is an integrated part of the carburetor assembly, attached to the side of it. So not a separate stand-alone pump assembly.
Issue: My motor won’t stay running unless I continuously pump the fuel bulb. If I don’t pump it, the motor runs out of gas and dies. Seems to start and run OK as long as I can manually pump the gas bulb.
Background and what I have checked and done so far:
• Early summer, after the engine sat over winter it wouldn’t start, I saw that the gas had crystallized inside of all the fuel lines and fuel filter area. From gas tank all the way up through the filter area.
• I replaced the entire gas line and bulb from the gas tank to where it plugged into the engine. It was an after-market line assembly.
• I then took the motor in to get it serviced at a boat shop. The rebuilt the carburetor, tuned it, replaced plugs, replaced the two fuel lines inside the engine (the one running from the entry valve to fuel filter and the other line that goes to the fuel filter into the fuel pump).
• My boat then sat in the driveway (I never ran it after getting back from the mechanic) until this fall when I took it out and my engine would not stay running unless I pumped the gas bulb.
• I then replaced the after-market gas bulb I previously installed, with a new with an OEM bulb, thinking the after-market one was defective.
• I then thought maybe it was the fuel pump and was not sure they rebuilt it when they were servicing it. So I replace the gasket and diaphragm in the fuel pump myself. I did not replace the pump body which is a plastic part with the two valve flaps and spring. They seemed to work OK and moved freely.
• I checked for vacuum/pressure leaks and could not detect any inside from the fuel filter down to the entry connection. From the bulb into the engine valve/connection seems air tight also.
• Gas flows pretty freely when bulb is pumped into the filter assembly, so does not seem blocked or restricted. Also checked the two fuel lines inside engine to be sure and those are clear.
• Here is one possibility where I detected a vacuum issue - I pulled the siphon hose assembly that is down in the gas tank. When I press the gas bulb I can hear a very slight leak somewhere on the fuel gauge or where the hose attaches to the nipple on it. Tightening the hose clamp does not fix it. It is extremely (very) small hiss, but seems way too small to cause no fuel to flow. I have to squeeze the bulb pretty hard to make it do it also..normal pressure doesn't seem to be enough to make it hiss. Would a pin prick leak stop the fuel delivery? My gut tells me it is way to small to be the issue and that I have to press so hard to get it to do it. I may be completely wrong though.
At this point, I feel I’m throwing money at it hoping something works, so before I buy a new gas tank I don’t need, any ideas on other things to check or potential problems? Maybe the mechanic didn’t rebuild properly and missed something?
Thanks for any help.
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