Fuel problem? Ethanol problem?

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Kevdon22

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Apr 16, 2012
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32964
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I have a 2000 Aquasport 215 with original Merc 250 HP Carb engine. All fuel has 10% ethanol in NJ.
Most of the summer the engine ran the best ever. We had heavy rains circa 9". Added some new fuel as tank was below 1/4.
Around Labor day, I started the engine, gave it a long warm up and started out to take guests for a ride.
Did not reach the Bay, engine died while idling out of lagoon. Fought by way back to dock by by pumping the throttle. Found the engine would not idle well. would run fair at dock at higher RPM, but would die at RPM below 1000.
Mechanic came, changed filter, tried to clear "carb" but had to remove for rebuild. No debris or water in fuel from old filter.

Mechanic Rebuilt carb, installed, idled beautifully, loaded spring lines at dock, engine OK.

First outing to bay, engine powered up well but would loose power at planning speed in moderately rough water.
Returned to dock, still idles OK.

Added Startron. Took it out again in calm waters, runs like a charm at all speeds.

Added stabilizer. Yesterday, took it out again in calm water, ran ok at 3300 rpm until I hit some wake. Pumping throttle to keep running and ran OK again with no wake.

Seems like rough water stirs up something or affects carb that causes loss of power.

Wouldn't new filter catch debris?

I thought that excess water would ruin entire tank not just pockets?

Could something be loose in Carb that is affected by rough water?

Any comments appreciated, want to resolve before winter storage.
Thanks
 
quote:
Originally posted by pdecat

Check the filter for water again

Click to expand...


Also check hoses for delamination, especially the inner part.
 
Thanks both good suggestions.

I'm curious, how do you check the hose for de-lamination on ID? Except for the ends, very little is visible

I have been somewhat suspicious about the hoses because the design of the fuel vent line us under the fill cap and it has on several occasions filled with fuel and caused a backup in the fill line. This means that fuel lies in both the fill and vent line for extended periods until I blow out the vent line.

I have been thinking about relocating the vent line outside the fill cap to stop fuel from entering when filling which often happens. I don't see how the under the cap vent works, there appears to be a small hole in the top, not sure.
 
Were all the carbs cleaned/rebuilt/floats adjusted/ synched? You used the singular term.

Rule out fuel quality issues by ride-testing with a clean portable tank of only all-new fresh fuel without all the additives , hooked to the engine .

Do the engine ignition wires/cables still look to be in very good shape and do you see any moisture on them. Just to help rule out moisture grounding out a chafed or cracked wire it can't hurt to spray them all with WD-40 or silicone after confirming all the engine ground connections are corrosion-free and tight.
 
Tied in with wakes makes me strongly favor water in fuel. How bad was the wake? A normal rocking wake or a jarring one that could shake loose wires, but if that were the case it's unlikely it would get better after the wake. How soon after the wake did it run rough? If you stir up water in the tank it will take minutes to reach the engine with all the fuel in the filters and lines.
 
Sandy,
My mechanic rebuilt the Carb, it's a simple 2 bbl. I trust the guy, he is an experienced mechanic, and he billed me circa $345 including 3 visits to boat and a rebuild kit. Anyone could make a mistake or get bad parts. What kind of mistakes could explain the symptoms? I wanted more thoughts from experts before I got back to him and I don't want to piss him off since he also hauls and winterizes the boat every year.

I was thinking about asking the mechanic if he has a portable tank, I think he uses one to winterize engine, good suggestion. Can I purchase a portable tank hookup, consistent with existing connection.
 
He probably did a decent job but why did the caeb fail? probably water. Where id the water come from and was this initial cause of the carb failure fixed??
 
Good point, thanks,
The mechanic initially suspected that the tank needs to be pumped out but decided it was not necessary after checking the fuel in the old filter that showed no signs of separation.

I have this "fear" that the tank needs to be pumped out and the fuel disposed which is costly and more complicated.

Want to make sure this is the root problem before going this route.
The question is- Given the symptoms does it make sense that the problem only appears when the boat is run in rough water??

I have been led to believe that when E 10 goes bad, it's the entire load of fuel that goes bad since the separation does not occur as with E 0 fuel.

Maybe I am learning the hard way!

Is there another test?
 
Recheck the filter. Dump the contents into a container and see what it looks like.
 
I had same issue. Used K100. Used 5 bottles. It encapsales the water. Read about it. Saved me tons of money as was about to have my tank pumped out. Changed filter few times.
 
I would not expect a fuel problem, unless you bought from a source that was suspect. I am assuming that sense you ran boat all summer that fuel was fresh. Also that it runs fine in calm water attests to this.

Do you have a fuel/water separator as well as fuel filter? If it is a water problem then water should be showing somewhere.

Maybe I missed it, but no where in your writeup did I see that the fuel pump was checked.

I do not think that your initial problem was ever solved. It is just too much coincidence to have another problem that has similar symptoms.

With nothing wrong showing fuel in filter it makes this a puzzle.

I am not familiar with that boat. Is it an IO or outboard?
 
quote:
Originally posted by Kevdon22

Sandy,
My mechanic rebuilt the Carb, it's a simple 2 bbl. I trust the guy, he is an experienced mechanic, and he billed me circa $345 including 3 visits to boat and a rebuild kit. Anyone could make a mistake or get bad parts. What kind of mistakes could explain the symptoms? I wanted more thoughts from experts before I got back to him and I don't want to piss him off since he also hauls and winterizes the boat every year.

I was thinking about asking the mechanic if he has a portable tank, I think he uses one to winterize engine, good suggestion. Can I purchase a portable tank hookup, consistent with existing connection.

Click to expand...


HOHO... Kevdon- so sorry about the carbs plural question . For some reason I read Merc 250 and the outboard image popped into my shrinking noggin.

I believe you can likely use any good clean outboard tank and compatible hose. It worked fine testing my 330 hp MPI I/B's underway at high rpm. But don't just make one run if it seems to work OK.

Just remove the motor-end connector and insert a 3/8" barbed hose splice fitting there and on the hose from your remote filter.

Or use a 3/8" barb x (?")NPT adapter fitting to connect your tank to the fuel pump inlet.

If the hose has a primer bulb on it and the engine still stumbles at the usual rpm, try pumping the bulb.
 
Water won't mix with gas, BUT alcohol mixes with gas and water mixes with alcohol, which makes water in gasohol readily burnable...up to a certain point. After a certain percentage of water in alcohol, the water starts falling out of suspension and separates. What this can do is end up filling the carbs float bowl with water which closes the fuel inlet. Since the water won't burn, the 'fuel' level won't lower to open the float valve to let in more fuel.

This separation of fuel, alcohol and water is also happening in the fuel tank and there can be a level of water in the bottom of the tank.

You can do a little test. Put a couple cups of gasohol in a jar and add a tablespoon of water and shake it up and let it sit. The water should mix with the gas and not show as a separation in the bottom of the jar. Then add a few more tablespoons of water and shake it up and let it sit. The water should fall out of solution.
 
mdoherty
"Tied in with wakes makes me strongly favor water in fuel. How bad was the wake? A normal rocking wake or a jarring one that could shake loose wires, but if that were the case it's unlikely it would get better after the wake. How soon after the wake did it run rough? If you stir up water in the tank it will take minutes to reach the engine with all the fuel in the filters and lines."
First test it was moderate wind driven wake.
Second time no wind It was pretty mild wake, nothing jarring, but after a 180 turn.
Seemed to have problems fairly soon, didn't time it, my mistake.
I pumped the throttle and it recovered quickly when I was not in wake, probably recovered within 20 seconds.

Sandy, My bad I should have mentioned that it is an IO and a 5 L engine.

gcolton
I have not checked the fuel pump nor did my mechanic. I assume since fuel is injected when I pump the throttle there is gas in the carb. Bad assumption? I should probably change the spark plugs, but don't think that is the problem.

There is no separator, just a spin on filter and the small filter at the carb. inlet.

Thanks for all the good suggestions.
I now have a plan at least before I bother the mechanic
Check filter for water,
Look into K 100,
Make another test run to observe timing of Power loss.
Check mechanic for test tank.

Appreciate your help, Thanks again
 
You have water/nasties in the bottom of the tankk. Your fuel pick up is about 1 inch off the bottom of the tank. When you hit rough water
some of the water/nasties hits the fuel intake and causes problems. Take out the fuel sender. Get a "Little Red Suction Pump" from Walmart and about 2 of 3/8 copper tubing. Insert tubing in the suction hose and put the tube in the tank and pump the water off the bottom.

This only takes about 20 minutes and should be done every 2 years as a PM measure on any boat that sets a lot. This religion with some houseboaters.
 
If you have the original fuel lines replace them. I had a similar issue on a Mercruiser I/O last year when I started using ethanol. Boat would stall starve for fuel in rough water, then smooth out later. Fuel filter was full of what looked like black pepper (turned out it was pieces of the fuel line). When I pulled the carb it had debris in the bowl that would slosh around and cause a problem. After a carb rebuild it ran much better, but after running at higher rpm (4000rpm to wot) it would stall like it was running out of fuel. I would limp home and after a few hours it would run fine until another high speed run then the cycle would repeat. In my case tracked down everything in the fuel system. Tank was clean, filters, clean, turn out the fuel feed from the tank (original to 1999, but A1 rated) was delaminated on the inside and would collapse at high rpm (ie higher suction on the fuel line) replacing the 4ft of fuel line from the tank to the filter fixed (i had a metal line from the filter to the pump and on to the carb.)
 
easy way to validate that its not your fuel or fuel lines. get a portable gas tank and hook it to the engine. if the problem goes away you know you are picking up something from the bottom of the tank or the fuel lines are going flat with suction.
 
The boat is 14 years old and the bottom of the tank has never been pumped. Guess what?
 
OHB Some people just enjoy complicated solutions.
 
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