Water or Ethanol Problem or just plain broke

"5.7L Merc w/ 2bbl mercarb, po

"5.7L Merc w/ 2bbl mercarb, poly (plastic) fuel tank.

Boat has been idle on the trailer for about 2 months. Ran it a couple times just to keep the batteries fresh.... no problems.

On the way to the boat ramp, I added about 30 gallons of Citgo 87 octane... never had any problems before. Engine started and ran fine for about 30 minutes. While trolling, and after catching the first (and only) fish of the day, the engine started sputtering and would not idle.
I could get it to fire and it would stay running only at a higher RPM, or if I would keep pumping the throttle. Needless to say, I headed back to the boat ramp. It seemed to run OK at about 3000 RPM. Once I got to the no wake zone, I tried to slow, but if I went any lower than abot 1400 RPM, it wanted to die.

I replaced the fuel filter. There was a little debris in there, nothing absurd. I didn't see any water. The fuel didn't have any unusual color or off-odor.
I tried to run it again, still wouldn't idle.

Any ideas?"

"Does it have a distributor? I

"Does it have a distributor? If so, points or electronic?"

From what I have read the etha

From what I have read the ethanol only effects fiberglass gas tanks not Polly or aluminum. So i don't think its that

Troy: Is the flame arrestor ni

Troy: Is the flame arrestor nice and clean?
Carburetor sounds like it is flooding at slow speeds due to the bowl float setting changed from age since it runs wide open but won't idle.

Old plugs finally fouled from trolling a merc. 350; choke not operating properly or hanging up due to gunk. Choke's bi-metal coil can weaken over time and change it's setting. Distributor cap and rotor OK? Rotor not corroded or cap is carbon tracking or cracked? I would check the plugs first for fouling--electrode color should be light tan if running right. Black means fuel fouling due to flooding. Then it is the choke or float setting. Good luck.
Guy

"Plugs, wires, rotor and dist

"Plugs, wires, rotor and dist cap are fairly new, less than 6 months. The ignition system is electronic (Thunderbolt IV). The choke was full open. I did try runnning it with the flame arrestor off, no difference, and it's clean anyway. I was leaning more toward a fuel problem, but I'll take a look at the ignition too. Would a bad coil act like this? I'm not at all excited about tearing the carb apart.
Thanks."

".."I'm not at all exc

".."I'm not at all excited about tearing the carb apart"

Sounds to me like that's what you're gonna have to do, partner. The Hugo Chavez crap you put in there must have been contaminated, possibly by someone who hates that swine's politics. (Seriously.) CITGO is changing some of its stations to Power something to get away from the negative publicity that rat who owns them has generated, but....

I once ran into some contaminated gas that drove me nuts. See if this doesn't sound familiar: RV would run okay but wouldn't idle right. Pulled carb apart and found light brown ?? in bowls, so fine it passed through the fuel filter. Ended up draining the tank and adding THREE in line filters to get rid of it. And I am positive that got it when fueling up at a gas station in New Jersey.

Jeff"

"I'm not a big fan of Citg

"I'm not a big fan of Citgo either, but it was convenient... it was on the right hand side of the road, the pumps had plenty of space between them... blah, blah, blah. I need to find a Shell or BP on the way to the boat ramp. This trailering the boat is turning out to be a pain in the butt!

When I changed the filter, I did notice a little brownish tint to the gas. Wasn't sure if it was from the gunk that was in the filter of the gas itself. I think my next step will be to draw off a sample in a glass bottle from the bottom of the tank and take a look at it. In parallel, I can get a gasket kit for the carburator or order.
Worst case... I drain the fuel and burn it in the truck, a little at a time and pull the carb apart and clean it out. Might ought to go ahead and put another fuel filter in there too!"

""I'm not at all excit

""I'm not at all excited about tearing the carb apart."

I gotta Agree,....
It Sounds like there's some Crap plugging the Low Speed Circuit.....
Time for a Carb Rebuild........."

Troy and others:
I read a c

Troy and others:
I read a consumer's report a few years back that discussed testing the big gas co's fuel for quality. Valve fouling over a given period of time was part of the test. Results of the test stated BP gas was near the top of the list along with Clark gas for fouling valves. I assume BP and Clark took notice of the report and reformulated their gas. Maybe not. Your choice.
Guy

"The reason it doesn't idl

"The reason it doesn't idle is you have water in the float bowl blocking the idle jets. Pull the carb off and turn it upside down dump the old fuel and water into a container look for the water. You may get away without a rebuild. Water is fat and will not go through the idle jet as gas will. Gases atomic structure is less dense then water, thats why it gives us problems in fuel systems. With this new style gas, I do about 10 of these carb pulls a year. Half I rebuild half are ok after getting the bad gas and water out"

I'll get the carb pulled o

I'll get the carb pulled off today. I'll definately dump the gas out and take a look before I tear it apart. I have a rebuild kit 'en route just in case.
I'm going to pull off some gas from the bottom of the tank and take a look at that too.

"Hey, Troy, I had that brown c

"Hey, Troy, I had that brown crud in my carb as well when I was having that problem.

And I agree: trailering sucks!

Jeff"

Dump the water out of the fuel

Dump the water out of the fuel bowls. You may be able to take the top off the carb and see exactly whats going on. Water sux. Citgo sux. Trailering sux. But Boating rox!

"The carb is out and in a gazi

"The carb is out and in a gazillion pieces on the workbench.
There was some goo clogging the low speed jet and aboat half a dime's worth of other junk in the bowl. The goo was kind of weird looking, almost like ear wax in consistancy. I have no idea where it came from or how it got there, but that appears to be my smoking gun.
I drew off about a half gallon of gas from the bottom of the tank. No water, no debris... clear and bright.
The rebuld kit arrives tomorrow, I should be back in business with two more weeks of striper season in VA Beach!
Thanks for all the inputs, everyone!"

"Hey, Troy: Be sure you have

"Hey, Troy: Be sure you have a nice, big, metal can filter before your carb, for it's likely more of that crud will show up there.

Jeff

PS: Please don't place the filter before the fuel pump! Even Crusader has made that mistake (though they changed it later, in a service bulletin)."

"Troy: the "almost like e

"Troy: the "almost like ear wax in consistancy" is called VARNISH from OLD FUEL. It develops in small quantities over time and you experienced the results. If you have a mechanical fuel pump, check the outlet tube of the pump leak hose (CLEAR) going to the top of the bowl. I found mine plugged with that "ear wax" and it would have caused a fire if I had a major malfunction. I change the 17 year old pump and found all kinds of goodies inside of it when I dismantled it.
Guy"

"It's back toegther, and r

"It's back toegther, and runs great.

Regarding Jeff's comment on the fuel filter, I have a fuel filter / water seperator, but it's in line before the fuel pump... orignal equipage. Don't blame me for stupidity, that's where Merc put it.
I could re-plumb the set-up, but with the exception of the build up of the goo in the float bowl, it seems to be working fine. I think that's more a chemistry issue rather than a foreign material issue. I'll likely never pinpoint the cause of the build-up. It may have been there for quite some time and just choose last weekend to become loose and clog the low speed jet.
There is a very fine screen basket type strainer at the inlet of the carb. It's funtion, I beleieve, is to catch chunks of the fuel pump diaphragm, should it decide to become un-wholey.
So, now that the carb is clean, the fuel in the tank has been verified clean and free of water, and I'm a little more sensitive to making sure there is stabilizer in there for extended lay-up periods, I'm not seeing what a filter after the fuel pump will do for me, that's not being done by the gear that's already there."