Honda BF130 - Water in Fuel System

[cricketman]

I have a Honda BF 130 on the back of a 12x50 Catamaran Cruiser (a catamaran-style houseboat). It's a 2000 model, and has given me great service for the last 16 years.

Recently however, it left me stranded (not fun being towed in a 12x50 houseboat - but thank goodness for Sea Tow!).

The verdict was water in the fuel system, so we added a water/fuel separator between the tank & the engine, replaced the fuel hose that runs from the tank to the engine, and replaced one fuel line on the engine that had a broken plastic fitting on it (which may have happened during the checkout/repair process but that's fine - must have had a small crack so glad it's replaced).

After those repairs, the next weekend she cranked right away & ran fine for the 30 mins it took us to get to a beach to set up camp for the weekend.

Then on Sun evening when it was time to head back to the marina, she wouldn't crank. Suspecting water in the fuel again, I first checked the new water/fuel separator we added between the tank & the engine. Removed it, dumped it into a clear jug and it was all fuel - not a drop of water. I then removed the pressure check bolt from the fuel pump and ran the pump some - sure enough there was water there. We pushed out two 16 oz bottles that were about 80% WATER before we started getting pure fuel again.

She then fired up, ran rough for a minute or so, then settled out & ran like a brand new one for the 30 mins back to marina where she sat in a covered slip for the last week.

Then this past weekend, same scenario - cranked fine on Friday afternoon, got to beach fine, then on Sat would not crank. Checked the water/fuel separator again - all clear - no water. Removed that bolt-plug from fuel pump again & ran over a QUART of water out before getting to pure fuel. Then she cranked fine & we got back home.

I cannot figure out WHERE this water is coming from!

It is definitely getting into the system somewhere between that new water/fuel separator filter & the fuel pump.

I see no indication of any gas leaks anywhere.

When we're "at rest" at a beach, with the front of the boat pushed up on the beach, the rear sits a little lower than it does when she's level in the slip which results in the exhaust ports on the engine being under the water an inch or two. Someone this weekend suggested water could be entering through those exhaust ports, but I didn't think that was possible - thoughts? (I am not an engine expert so forgive me if that's a stupid question.)

Any and all thoughts are greatly appreciated!!!

 

[km1125]

Someone this weekend suggested water could be entering through those exhaust ports, but I didn't think that was possible - thoughts? (I am not an engine expert so forgive me if that's a stupid question.)

It definitely couldn't be entering a fuel LINE through the exhaust ports. If the engine was getting hydro-locked, then yes, that could happen but not water into the fuel line by that method.

Is there any part of the fuel system that dips below the water level when the boat is up on the beach?

How can you get a quart of water out of the fuel pump if that same water/gas had to go through the water/fuel separating filter first, and you didn't see any water there? Is there that long of a hose from the filter to the engine?

 

[cricketman]

None of the visible parts of the fuel system dip below the water when it's beached.

The entire fuel line (with the bulb on it) from the tank to the snap-on connection on the engine is now secured out of the water. That was NOT the case before - that fuel line actually hung down in the well of the engine transom mount (which stays full of water), so it was always covered in water, and we thought that was where the water probably came from the first time (it was the original fuel line - 16 years old! - so surely had some hairline cracks in it) - but now that's been resolved with new fuel line that is tied up above the engine well.

When I remove the engine cowling, I see a little water in the bottom of the engine compartment, maybe 1/2" (or slightly more deep in the deepest places), and there are indeed a couple of fuel lines that sit perhaps partially covered in this water... I wondered if one of THOSE lines might have a pinhole and could be sucking in some water when the engine is running (would there be a vacuum in those lines to pull fuel to the engine or would there be positive pressure inside those lines created by the fuel pump - in which case if there was a pinhole I would see a gas LEAK, right?)

I don't think that lower part of the engine housing has any drain holes in it... so I believe the water I see inside has just trickled through the seam where the cowling joins the lower part of the case, or some that gets in through the elongated exhaust openings on the top sides of the cowling (when I wash the boat I'm sure some gets squirted in those elongated openings).

The fact that I got a quart (at LEAST) of water out of the fuel pump AFTER the line goes through the new fuel/water separator is definitely perplexing, and it confirms that the water is NOT coming from the fuel tank, but HAS to be getting into the system at some point PAST that fuel/water separator. There is a very small (2 or 3 ounces?) fuel/water separator on the engine near the fuel pump, but I do not see how to remove/empty it.

The really strange thing is that (while we were beached) I pumped nearly a quart of water through the system (removed kill switch, removed pressure test plug from the fuel pump, had wife turn key to rotate engine while I held empty plastic bottle under fuel pump). Once I saw clean fuel coming out of pump, I reinserted fuel plug, engine cranked pretty easily, ran rough for about 30 seconds (little more water pushing through I assumed), then it settled out & ran like a brand new one.

I let it run at idle for about 5 minutes before shutting it off. Then it sat (still beached) for about 5 hours till we got ready to head home, and when I tried to crank it, same situation - would not crank, and I ran ANOTHER QUART or MORE of water out, then she cranked fine.

See this pic?... this is a half-gallon OJ bottle... this is one of THREE TIMES I pumped this much water through before she started pumping pure gas.



After this, I then drove her 20 mins or so to get back to slip.

After docking, I shut it off, let it sit for about 20 mins, then tried to crank it again (to test my theory that maybe those fuel lines in the lower part of engine compartment that are partially covered in water had sucked up more water on the trip back across the lake), and it cranked fine & sat there purring like a kitten for 5 minutes before I shut it off.

So to me, that kinda negates the theory that those lines inside engine compartment are sucking up water.

I don't pretend to be a mechanic, but I do have a little mechanical acumen, but... this one has me baffled!

 

[Sea Rider]

Is OB well height transom seated ? that's not having back or back water splashes over transom and side OB as well when on plane ? Middle pan, where powerhead sits should have drains for water sitting there to exit freely. Is cowl's lower seal in good shape, same as hook. ?

Happy Boating

 

[cricketman]

Not sure what you mean by "Is OB well height transom seated"?

There is very little water that splashes anywhere up onto the engine during traveling, as top speed at WOT is only a snappy 10 mph.

I have not CLOSELY inspected lower seal of cowl, but I have not noticed any damage to the rubber seal when removing/replacing it (which I have done more times that I'd like in the last few weeks!) - but I will check it closer.

So, you're saying that the "middle pan" where powerhead sits DOES have drain holes in the bottom? That means any water that is accidentally splashed in when the cowl is off (or that enters through the elongated exhaust vents on top of cowl when I'm washing the boat) should be able to drain out, right? And I assume those holes are located in a place that would prevent water coming IN through them while the boat is sitting in the water? What about when pulled up on beach which forces the engine down a bit lower than normal sitting-in-water position - could those holes be taking on water then?

Where exactly are those holes located (I looked in manual but don't see them).

Thanks to all for your responses & thoughts!!!

 

[km1125]

Well, is it possible that your water/fuel separating filter is not doing it's job, and that you're really sucking up what's at the bottom of the fuel tank when the boat is inclined up on the beach?? Then when the boat is sitting level the tank pickup is too high to get the water at the bottom?

I see how much liquid is in that jar and think where that all had to be before you pumped it out. That had to be enough to fill the fuel pump, all the lines, and the water/fuel separator, and maybe more wouldn't it?

Is it possible the water/fuel separator is not connected properly and you have the "in" and "out" hoses actually connected to both "in" or to both "out" ports (some have several different ports to accommodate various installations), so most of the fuel is really bypassing the element?

I think if you had big enough leak in hoses to suck water in, then you'd be sucking air most of the time the engine was running and would have trouble keeping it running. The only one that wouldn't fit that category would be after the pump, and would leak fuel as you'd guessed.

 

[Sea Rider]

We're talking about portable or internal fuel tank ? If internal, remove all fuel, probably has lots of water sitting at bottom. If that's a 2 stroke OB all those mentioned rubber small hoses are lubrication pipes.

Happy Boating