Mechanics stumped on my bf50 stalling.

[alphadog808]

Hi guys,
I have my 2015 Honda BF50(~250 hours) at the mechanics and they have had it for about a week and they can't figure out my stall problem...hoping you could maybe assist.

Background..was fishing the other week and after idling for an hour or two, when I'd go into gear to move, the engine would die about 20 seconds in. I would restart the engine and it was fine. I moved to the next spot, and when I went to move again(1-2 hours), it died. No biggie, right? Of course, when we decided to go home, the engine died like before. I restarted the engine assuming we'd be fine...but no, it died again. It did it about 3 times. Finally, I ran the boat at a lower RPM, and started chugging home. About 20 minutes in, I decided to chance it and I revved up the engine and to my surprise, it didn't die and we raced in(~15 miles). No problem.

Note, I changed fuel tanks and I had the same prob with both tanks.

Went to the harbor the day after, took off the prop and ran the engine in a bucket. Idled for 30 min and put into gear. No problem. Idled for another hour and it died when I put it in gear. However, at this point, I couldn't even start the engine. I took the boat home and 3 hours later I fired it up and it started on the first crank.

Took it to the mechanic and they did the usual checks and diags and they said everything was ok, no hose leaks, gas was good, no errors, cooling system looked ok, compression good, checked the VST, etc. Had them try to idle for a long time and then put into gear...they couldn't reproduce it.

Also wanted to note, the engine had been stumbling at 4k RPM a while back but the mechanic had changed out the high pressure fuel pump as he said it was out of spec. Otherwise he didn't find anything amiss. I think it ran fine after that change.

Last I heard they were thinking/hoping the grommet on the high pressure fuel pump might be blocking the fuel so they are going to check that...other than that, any thoughts?? Only other thing I can think of is I recently changed my racor fuel filter(S3240), but the mechs didn't see any residue/blockage in the vst and it ran fine when I booked it home the day I had this issue.

Thanks in advance!

 

[Sea Rider]

Was the new Racor fuel filter exact same as used before ? If complete fuel system is doing its homework right, could be electrical related, a component heats up and misses, cools down and works fine to start all over again. Intermitent electrical failures are the most difficult to troubleshoot. Need to run that OB at idle for extended time periods for trolling purposes ?

Happy Boating

 

[ahicks]

The grommet idea hasn't been thought through very carefully. There's no way on earth that grommet, any grommet, that's restricting fuel flow, could get out of the way and allow the engine to run normally under certain conditions. A grommet would be more of a pass fail thing. It works, or it doesn't. Same with components in the fuel path (line's & filters). They can either pass adequate fuel, or they can't. That's not a "sometimes" thing either with a problem like you are describing.

That leaves the pumps, the relays that control them, wiring, and other electrical/electronic components. That's where my focus would be anyway.

 

[alphadog808]

Thanks for the input guys, I appreciate it. It's the same fuel filter-just was replacing the old one. And I agree with the grommet thinking, but that's what they told me. I don't feel too warm and fuzzy with their supposed solution. Worst case, I get it back and run it in the harbor till it fails again.

 

[Sea Rider]

Rubber, plastic grommets won't restrict, air, water, fuel passing through them, if severely worn will just spill air, water, fuel around where it connects to other mechanical elements. Pour an overdose off Sea Foam on tank, on next outing avoid idle throttling, go for long wot runs, check if that cures it. Outboards specially 2 strokes doesn't like to idle for long time periods, plugs are fouled very easily, don't know if with 4 strokes OB will be an isue in the long run ?

If Sea Foam doesn't cure the issue, OB could have an electrical related issue for sure, time for patient and time demanding electrical troubleshooting with proper multimeters, testers whatever is needed.

Happy Boating

 

[alphadog808]

We used to put seafoam into our 2 stroke...is it safe for a 4 stroke? I figure I could dump in a whole bottle and let it smoke.

 

[ahicks]

A lot of us run Sea Foam in every tank of gas to prevent fuel related issues. Unless you are using the engine frequently, like several times a week, I think Sea Foam in every tank is a good plan. Like an apple a day keeps the doctor away?

Here, it sure won't hurt anything, but I wouldn't hold my breath or venture too far from port....

 

[Sea Rider]

To be confident that won't be left stranded alone at sea, ask a boating mate to follow you while doing wot tests. Just for the record, report if Sea Foam did miracles or intermitent issue continues.

Happy Boating

 

[alphadog808]

For sure. I think I'll run it in a bag first for a while. If/when I do take it out I'm definitely not straying far from home until I'm sure it's fixed!

 

[ahicks]

One idea, the next time it acts up on you. Check to see if your fuel line primer is hard. Wondering if you might have a tank venting issue. If it's soft, see what happens when you open the fuel cap.

 

[alphadog808]

I know when it failed, the bulb was NOT hard. I know because I primed it back till it was hard. I think I'm picking up the boat today(they couldn't find anything) so I'll check the venting as well. It failed on both tanks, so I'm guess both vents couldn't be blocked/bad, but who knows. The gas tanks weren't caved in.

 

[Sea Rider]

The primer bulb is only firm when priming the engine prior starting it, when started and running bulb is somewhat soft, open air vent fully out, unscrew tank cap several turns upwards or remove it momentarily, check if with same issues.

Other alternative. Connect hose to tank, remove cap, maintain front connector valve open while priming bulb several times to check fuel flow if with restrictions or running as it should. Place a container to receive fuel while being primed.

Happy Boating

 

[alphadog808]

Update-so the mechanics couldn't find anything. At best they cut the grommet on the high pressure fuel pump(wasn't clear if they cut it or if it was already cut from a previous replacement). They had me pick up the boat and gave me a new 6 gallon tank and hoses to connect to the motor to see if I could repro the problem, assuming I could repro it in the first place.

I went to the washdown, idled for 1.5 hours and put into gear(using my usual tank) and I couldn't repro it. Dang. Replaced the fuel filter the next day and my friend and I took the boat out and anchored near the harbor and idled for 1.5 hours and then drove around. No prob. Tried again for another 1.5 hours, No prob! Not a single hiccup to even hint anything was wrong, it ran flawlessly.

Not sure why the problem isn't happening anymore, but I'm going to have at least one or two inshore adventures before trekking back out into the deep blue. I have removed all the ethanol gas and am going to run non-ethanol for a while, if not permanently...at least if the problem happens again I'll know it's not due to the ethanol fuel. I think I'll start putting in some seafoam every few fill ups as well. Can't hurt, I figure...

BTW, I took off my vent for my tank and it's clear. I did notice the vinyl inside was starting to fall apart, so I'll be replacing it as I don't want parts of it falling into the gas tank-but there is more than sufficient airway for it to vent properly.

 

[ahicks]

I've read where several people have had the inside of the fuel line collapse closing off the fuel supply. I'd be tempted to keep the replacement fuel line with the amount of trouble you've had.

I'd pull the tanks down completely to make sure they're venting properly and fuel can flow freely through all components - including the couplers. If your fuel line pick up inside the tank isn't too difficult to remove, a careful visual inspection of that might be in order as well. Confirm it's not cracked allowing air to enter and there's no garbage in it, and that it can flow freely.

 

[Sea Rider]

There were some old fuel lines that had double sleeves, an internal and an external one, The internal used to collapse in pieces due to being made of bad quality material and clogging the fuel delivery badly. Fuel restriction was evident when purging fuel line while priming bulb..

Happy Boating

 

[ahicks]

Not limited to "old" fuel lines. The very newest are of a design the EPA refers to as "non permeable", designed to limit fuel vapors. Those are the more likely culprits I've been reading about. They're generally supplied with newer engines, which also come with gas tanks that a lot of guys struggle with trying to get them to vent properly.....

 

[211libwtfo]

Anti siphon valve!!!!!

 

[alphadog808]

Funny you say that...I checked the venting and the pipe was clear(I blew air threw it) but I did see the inside wall was coming apart. So I got some pipe to replace it. While replacing it, I cracked the attwood vent(I guess it was old) so I'm ordering another one. Outside of that, the venting seems fine...also, this problem happened on two tanks so I'm thinking it's just preventative maint. I also emptied the gas tank and looked around, There were some small particles at the bottom and one brown sheet(small about the size of a dime) floating around. Cleared those out and we'll see....