fuel tank question and newer engine overheat alarm question

[sebastien]

Hello C-brat community,
it's finally happened, just over a week ago we left Philadelphia for the great American loop - today we are at anchor on the Hudson North of the Tapppanzee bridge.

first issue I would love advice on:
the last hour of our delaware bay crossing from Cohancy river to Cape May
we had been running for about 1.5hours at 4000rpm from the port tank which was getting low (5 gallons or less) the RPMs dropped quickly and the motor died. the bulb on the fuel hose was sucked in.
We quickly switched tanks re-primed the ball, it started right up and we made it with no issues from the starboard tank.

I checked the air vent by blowing into it and it was clear.
There is no water in the bottom of the racor filter.
We filled up on fuel in Cape May and ran from the port tank again at 4000rpm and after a couple of hours RPMs dropped again the ball was sucked in so we quickly switched to the starboard tank again.. without even stolling the engine.

Since then we've run from the port tank again for a few hours at 4200rpm from manasquan inlet to Sandy hook with no issues.
(we've been running the port tank first so as not repeat the issue at the wrong time and to test how it is working before using the starboard tank)

Today we ran the port tank from the statue of liberty anchorage to to the Tappanzee bridge for about 8 hours straight all at about 2000 RPM (minus finding and towing a dinghy and handing it off to a friend of its owner) the bulb and motor ran great now there is about 4 or 5 inches of fuel left in it..

just as we were circling the small cove at near idle speed before finding a good spot to drop the anchor the temperature alarm and light went off on the remote control.
the alarm turned off when I lowered the RPMs even more or put it in neutral.

1) Any ideas what might be going on with the port fuel tank?
2) Is it possible that the motor simply ran too long too slow and just got hot when we arrived and near-idled for a few minute?
3) could there be a connection between the fuel issue mentioned above and the overheat alarm going off this afternoon?

thank you all!

[Barry Rietz]

With regards to question #1, it is likely the fuel tank being near empty may have picked up setiment from the bottom of tank. This would cause the bulb to experience a collapse. Remove the bulb from fuel line and apply light air pressure toward the fuel tank. Reassemble the bulb and try to pump fuel up to the bulb with it removed from the carburetor. If fuel comes out, there is a good chance the tank line did pick up debries. I would then suggest doing a through cleaning of both tanks.

[ssobol]

I would check the impeller for the overheat issue. On my BF90D I know that if there is a overheat, the engine RPM is restricted to below 2000 rpm. I don't know if this means that the ECU will prevent the RPM from exceeding 2K or if it means that if you try to run it above 2K the alarm will sound.

I have run my motor for long periods at low speeds and never had issues with an overheat alarm. IME you should never get an overheat alarm if the engine is run anywhere in the usable RPM range (idle to WOT) and is working properly.

[sebastien]

With regards to question 1.
I was thinking of removing the fuel hose at the tank to see if I could remove and inspect the pickup / screen maybe even aim the lens of my phone in there and take a photo of the state of the tank.
I’ve been concerned about disassembling things for fear of introducing air into the system but that seems unfounded(?)

Thank you for the advice - i have a 7 quart fluid extractor and a 2 gallon Kerry can I could drain that tank with..

[sebastien]

With regard to question 2
Yesterday after about 3 hours we decided to move a few hundred yards for the night because of waves from passing traffic on the Hudson reaching us.
When I started the motor up the light was on - at 1200 rpms the buzzer came on as well but as soon as I went to 2000 rpm to move both turned off and stayed off. After we re-anchored and I backed up on the anchor a little I reved it a little and went up to 3000rpm in neutral and both the light and the buzzer did not turn on again.
Maybe I should idle the motor for a while today at anchor to see what happens.

The impeller and housing were replaced less than 50 hours ago.

[Barry Rietz]

The entire fuel system is "open" to the atmosphere which brings to mind another possibility. Check the "tank vents" to be certain there are no restrictions in either line, both port and starboard. Since you are currently underway, what options have you to remedy these issues other than a tow?

[sebastien]

I’m not sweating the port tank issue too much, we ran it all day yesterday without a problem - I think I’ll take the pickup apart, inspect it and try to see in the tank before filling it up again.

With regards to the overheating light and buzzer
In question 2
I ran it about 30 minutes this morning and idled it at about 1500 rpm a few more minutes and the water coming out was cold and no light or buzzer. All I figure I can do is run it and if it happens again I’ll get it towed and repaired- I’ve got tow boat us and after the Delaware bay the Hudson feels pretty cozy if we’re adrift waiting.

[gulfcoast john]

Greetings Sebastien,

Re question #1, we had similar symptoms (overheat alarms at idle but not at cruise speeds) on a Yamaha F150 that turned out to be a stuck/grungy Pressure Relief Valve (or ‘poppet valve’). It opens and diverts cooling water into the exhaust at cruise speed, when the water pump is supplying much more cooling water than the engine needs. If it’s faulty or grungy, it won’t supply enough at idle and can be an intermittent problem. It’s a $10 spring like valve near the thermostat. Like thermostats in salt water, cruising owners often elect to replace them at annual maintenance. I don’t know if your engines have a PRV, but this seems an area worth exploring. Amazon can Prime it to your next marina. An engine internal corrosion issue would be more of a Houston, We Have A Problem on this cruise.

Agree with Barry that question #2 sounds suspicious for a tank venting issue. Check for smooth curves, mud dauber nests and possible intermittent kinks, that’s easy. The gas hose manufacturers recommend total replacement every 10 years, so you MIGHT be at end of life for your second set on a 2000 model. You can’t detect internal deterioration and it too can be intermittent. The mfg date is stamped on the hoses. And no, we have not replaced ours yet either.

We know you’re busy, but we all want to see your picture of Lady Liberty (nice NYC skyline pic) in your album! What are your plans on your most excellent adventure? If you need a non-warranty general outboard expert on the eastern Erie canal, Paul White at Pirates Cove Marina past Lock E-23 helped us out of bind with a 2-day turnaround when the famous Ess-Kay Yards couldn’t during the peak of Looper migration.

Hope this turns out to be helpful, and safe travels!

John

[sebastien]

Thank you so much for the advice re. The valve spring near the thermostat. I’ll look into it for sure.
I brought 4 feet of spare fuel hose, maybe after I inspect the pickup and the tank I’ll replace what I can for that tank.
And thank you for the heads up about that mechanic. It might really be great timing!

We post on Instagram at Sebastien_maker and my starlingdarling if you want to see more pics

[colbysmith]

Regarding the overheat, any possibility you picked up sea weed or some other blocker on your water intake? When you reversed that would have likely cleared it off the water intake screen.

[Almas Only]

If you want to check for fuel venting issues while underway, wait until the problem presents itself, then unscrew the fuel fill cap on the tank from which you're trying to draw fuel. That will expose the tank to atmospheric pressure. If the problem goes away, you have a vent issue. If the problem persists, forget about the vent.

If there's no vent issue, it's either something under the motor cover, or not. If the fuel bulb collapses, "or not" is the most likely place to look, since nothing going on under the motor cover will cause the fuel bulb to collapse when it has a ready supply of fuel from a vented tank. If the fuel bulb does not collapse, the problem is under the cover, and you've already gotten some suggestions for looking there.

If the fuel bulb does collapse, and the problem only presents with one tank, then look for a restriction in the fuel supply coming from that tank. STOP THE MOTOR, KILL ALL ELECTRIC OR HEAT SOURCES, AND PROVIDE VENTILATION FROM THE WIND OR ANOTHER SPARK PROOF SOURCE. THEN, disconnect the suspect fuel line at the tank, and the line at the selector switch OUTLET, let any fuel that want's to drain onto a cloth, and try blowing into the fuel line which you've disconnected from the tank. If you get air flow, you've got a blockage in the tank fitting or the pickup tube inside the tank. If you don't get air flow, disconnect the suspect fuel line at the corresponding selector switch INLET, and try blowing again. If you can't get air to flow, your blockage is in the line. If air now flows freely, look for a blockage in the selector switch.

If the fuel bulb collapses and the problem presents with both tanks, look for a restriction somewhere between the fuel selector switch outlet, and the fuel bulb inlet.

[ssobol]

You might also want to check the fuel bulb itself. There are check valves in there and one may have a restriction.

[sebastien]

First, re. The overheat alarm and buzzer:
Yesterday I idled and upped the rpms and nothing.
Today we traveled only 3 miles but after taxying I went straight to 5000rpm for the run and then we taxied for at least 20 minutes looking for a place to land the dinghy and no issue so I’m going to forget about it for now.. until and if it happens again.

Second,
The collapsing bulb issue is definitely only the one tank.
When it happened 7 days ago in the Delaware bay the second thing I did was open the gas cap on that tank to see if that would help and indicate if the vent was clogged. It doesn’t appear to be. Which to me indicates that the problem is in the tank with the pickup or with the line to the switch (yes it could be in the switch too!)

Again - since then we’ve filled up that tank twice - and once at high cruising speed the bulb started to collapse, rpms dropped and we just switched to our now “dependable” tank with no issue. A couple of days ago we ran on the “trouble” tank for hours at slow cruise (2000rpm) all day with no issue.

I will shut off all electric (good advice)
Disconnect the pickup and check that. If that looks clear and the fuel looks good I will disconnect the hose at the switch and check that. (So far the only date is see on fuel lines is from the switch to the racor and that says 1997 so my fuel lines might be really passed their prime)
I have 5ft of spare hose on board so if the hose looks constricted I’ll change the length from the “trouble” tank to the switch.
today it’s too nice to do any of that at half moon bay!
Mañana!

[thataway]

The one item not mentioned is the "anti siphon valve" which is the hose barb at the top of the tank, from the "El" at the top of the pickup, and the fuel hose goes into.

These boats/tanks don't need an antiphon valve, but ABYC calls for one. You can remove the anti-siphon valve, and substitute a hose barb fitting of the same size. I always try and carry an hose barb to elbow fitting aboard. Any hardware store should have one.

[colbysmith]

Hi Bob,
I had to replace my fuel pick up tube and the anti siphon valve this past year, as that piece broke when I removed it from the tank when I was doing some cleaning and replacing my fuel gauge sender. It almost seems to put some restriction in the line. Is that anti-siphon valve not necessary on the 25? I'm not going to remove it now, but would be nice information for the next time. Thanks. Colby