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oldtimer57.
06 Merc 225 Pro XS. History of fuel issue: Couple weeks back I left our tournament take off, went about 1/4 mile at mid speed, throttled to 3/4 speed and boat stalled like it was out of gas. Was low on fuel in one tank so switched tanks and wrote it off to “time to switch tanks.” Following week, left the dock for our tournament. No problem getting there, BUT water was rough so I never got over 3000 to 3500 rpm for the 7 mile run. Took off to fish and the boat did the same thing after 1/4 mile when I got up to 4000 rpm. Acted like it ran out of gas. Let it idle for awhile and it ran again, but I never ran it over 3000 rpm. No smart craft alarms, no Merc shut down. Following day I ran the boat until it did the same thing…again about 1/4 mile. Pulled the cover, took out the filter from the VST. There was only a half inch of gas in the reservoir. I started the motor to see if the primary (pulsating) fuel pump was working. It was. Also plenty of pressure from the compressor. If I pump the reservoir full by hand and take off full speed the boat runs great at WOT for about 1/4 mile and acts like it is out of gas. Pump it up and off we go again. Ive replaced the filter (it was time anyway) and leaning toward faulty pulsating fuel pump or restricted fuel line. It happens on either tank, so Ive kind of eliminated the hoses to the tank….but could be the hose from the tank switch to the motor. Is it possible for the pulsating fuel pump to slow down to the point of not keeping the bowl full enough for full throttle? Or maybe a float issue? Any thoughts? Something I havent thought of? Id be happy if pulsating pump, hose or float. And not the boost pump, etc. $$$$
It could be a split pickup tube in the fuel tank. You could be losing suction because of this.
Hawg Dawg. Good point. I was going to run it this evening on a portable fuel tank to see if it corrected the problem, but ran out of time. Will try this tomorrow. That could be the case, because now that I think about it, I did have a little trouble getting hose to prime.
We have seen pick pu tubes split where they are fastened to the insert barb. You can pull that and check the pick up for a problem. It is not that uncommon on limited occasions and would drive you crazy to find on your own. BCB
The symptoms you describe are exactly what happened to me and I almost never figured it out. You may have a collapsed liner on the inside of your fuel line. This has happened to me and after replacing fuel line everything worked great. If the liner has collapsed it may not be easy to see if it occurred somewhere in the middle and wouldnt be visible. I did the same thing you did as far as changing filters, pumping the bulb, etc. Nothing I did worked until I changed the fuel line.
Thanks all. I think Im on the right track. Replacing fuel line and checking pickup tubes today.
Two possible problem… (1) if the primer collapses, then there is a restriction. I have seen one case where the liner separated from the main part of the fuel line, and it is thin enough to collapse and shut off the fuel. Most likely caused by our good frient mr. ethenol. (2) primer is soft, indicating air. This is a leak somewhere between the primer and the tank. Of course you can have problems between the primer and motor, but that seems to be more rare. Do, by all means, avoid the cheapo primer bulb/fuel-line combos and buy something OEM. I cant count the number of times I have seen people report that an $8 primer/fuel-line was the problem even though it was just replaced…2008 Pantera Classic2014 Mercury Pro XS 200
The best primer bulb is the OMC/BRP brand equipment. BCB
Reporting all is well. Found collapsed internal lining on the fuel line from the bulb to the motor. Runs great now. Replacing bulb, fuel line and filter. Oldtimer57 I agree with you on the ethanol. We recently had a boat that sat in storage for a year or so, with no use. Merc 175 traditional carbs. The bulb and fuel line (black hose) had decayed so much that when we cut the bulb open to look inside it looked like a shredded tire. Thanks everyone for all the help. I was confident I was headed in the right direction, but it is always reassuring to get feed back on this site. Ive got nothing against paying mechanics (my dad was a mechanic and taught me well) but money is really tight right now.
The ethanol and water mixture is a bad one. Alcohol absorbs water at about a 50-50 ratio. And can produce an acidic reaction if you let it sit long enough. And once this starts, you really need to replace every last rubber hose, or you will be cleaning carb bowls, needle/seats, and jets for the rest of the year. Dont forget the hidden lines under the cowl. Carbed motors particularly have 3-4 extra hoses you might never think about to connect the three bowls, plus the primer lines. Neighbor just had a large (28″) tree blow down. He broke out his chain saw that he bought last year, used last year, and let sit full of fuel, and it would not crank. He then noticed it was leaking. We took it apart and the fuel line was brittle, cracking, and leaking air. I went back to the house and got my 15 year-old Stihl 034, cranked it up and cut the thing down off another tree and into firewood in about an hour. He asked, “why didnt yours crack like mine?” My answer was “mine wasnt stored full of fuel, I emptied the tank, ran the motor until the carb was dry, then oiled everything and put it away. And it cranks every time (still will knock a knot on you due to the occasional backfire when cranking) but it runs just as well as it did when I bought it. This fuel is a pain, regardless of what we are being told. its just like the R134c refrigerant fiasco. And it will undoubtedly not be the last such fiasco whenever the government gets involved.2008 Pantera Classic2014 Mercury Pro XS 200
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