Broke down today... Need suggestions please

diggin2day1

       So here's the full story.... We bought our FV270 this winter and have been using it like crazy since it hit the water in May. Started the season with a full(100 gallons) of fuel, burned/added 50 gallons a few weeks ago. We burned 70 more gallons in the last few weeks and intended to get fuel on the way home today. We were on our way to the fuel dock cruising at about 28mph and the boat was slightly porpoising due to chop/too much trim. To knock down the porpoising I trimmed it down a bit and heard the RPMs drop slightly and heard the engine change pitch as well(like it always does when it's not trimmed into the "sweet spot")... At that instant RPMs dropped way off and the engine started to sputter. I tried to get the boat moving again as we were about 1/2 mile from our marina and it sputtered/bogged then died as I pushed the throttle. My analog fuel gauge on my dashboard read "empty" but my charplotter(linked to engine via smartcraft) displayed 23 gallons left in tank. My first though was that I ran out of fuel and my chartplotter was WAY off. Luckily my buddy was following me and went and got 5 gallons of fuel for me. I added the 5 gallons from him and was able to get about 2 more out of my dinghy's outboard gas tank. I tried to restart it a few times but it quickly sputtered out again. We transferred our kids to my friends boat so they could go back to marina and we called SeaTow. After waiting for the SeaTow captain for about 5 minutes I tried to start it again.... Started up and ran fine! Went straight to the fuel dock and filled her up with 77 gallons of fuel.... My charplotter was DEAD ON! After refueling we got back on plane and cruised with no problems whatsoever. 
        One thing that made me nervous was the instant before the engine died(while it was sputtering out) I glanced at my oil pressure gauge and it was very low. Thinking that it was low due to sputtering/low RPM of engine(I hope!!!)... There was no alarms or warning lights at all. After we restarted the oil pressure was reading 50psi on analog gauge AND on the chartplotter/smartcraft. 
I was obviously not out of fuel... Any suggestions?!?! Fuel/water separator?!?! 

diggin2day1

.... And yes, I did call the SeaTow captain and let him know we were underway and to call off the help. 

brianflhrci

is the boat fuel injected or carbed?  Also, any fuel water separators in line?

diggin2day1

It is a fuel injected 350 mag horizon.... Yes, there is fuel/water separator... Didn't have time(or energy) to dig into it this evening. Heading there in the morning to change the separator and do some more looking into it. 

212rowboat

I'd guess your knock sensors reduced power 80% and shut you down.   All else being fine I'm guessing?  Blame fuel quality.   

Altering trim altered load while pcm had increased advance, which promoted predetonation.  Good fuel wouldn't have done that. 

brianflhrci

Ethanol is the enemy, we've had better luck with fuel injection but depending on where you fuel up it can be a huge pain in the butt.  We filled up last year early on and ended up replacing all of it since there was too much water in it.  Not that it helps but we ran on a separate set of gas cans until we found the issue and it pointed us in the right direction.

diggin2day1

It just seemed strange that it would stall with 23 gallons left in tank... And why would the 7 extra gallons make a difference(if it did at all?!?!). After adding the 7 gallons it didn't start right away... About 10 minutes later it fired up. 

212rowboat

Next time,  your pos cable off your battery, or of.equipped with a switch, turn juice off...  Let the pcm clear.  

If my suggestion is accurate, and you knocked the knock sensor, the pcm protects the engine until certain conditions are met.  One of those conditions is temperature.. The pcm figures the temperature could be the cause of knock, so, no go go till cool cool. 

diggin2day1

Hmmm... Thanks 212rowboat, it does make sense... Cooled way down before restarting. I just reread your reply about predetonation too... Any suggestions on what to do next? I just added 77 gallons of fuel AFTER this incident. 

212rowboat

Run with it and see what happens...

Fuel quality, or lack of, will allow predets easier than good fuel... Nearing the end of the tank you're likely pulling fuel with drops of water, which is unstable and more likely to predet... that, in addition to running consistent speeds/load, allows the engine to advance timing to the edge, quickly altering that by adding considerable load (down trimming, changing angle of attack) in the split second likely caused a few knocks, and serious enough to trigger the pcm's protection mode... 

This is all speculation, understand, but it's consistent with what you encountered. 

diggin2day1

should an alarm have sounded? I just checked your post "Encountering Faults" and it has knock sensors listed as alarm sounds. 

212rowboat

It should have.   depends on how quick it all happened.  does your smartcraft show current codes, past or pending codes?

If youve got access to a scanner, knocks are logged, too.. 

diggin2day1

It all happened very fast... Don't think I can access the codes with my setup... Engine communications link plugged into my engine via NEMA2000 to chartplotter. Thank you for all your help/suggestions, at least it gives me a direction to go in.  

diggin2day1

Changed the water/fuel separator and an inline fuel filter today... Started and ran fine up to operating temperature. Going out later for a cruise and see how she runs. 

diggin2day1

Alswagg: Would there be a genset pickup even if the boat was never equipped with a genset? Nope, no alarms sounded. Sounds like another reasonable explanation.... Was out on the boat all weekend with a full tank of gas and zero problems!

Dream_Inn

Well, I certainly won't answer for Al, but I would say there would be another pickup for the generator even if one was not installed.  It does sound like what Al described.

diggin2day1

How can I tell which is the genset pick up or the engine pick up?! Going to have to look into this some more. 

Dream_Inn

Good question for sure that I don't know.  I'd say at this point, take a look at your fuel tank and the pickup on top.  If there are two, then you'll know that it is a good possibility of being the problem.  Only other way to know is to run it down to where you had it before, close to home of course.

diggin2day1

Was thinking the same thing... Run it down to 23 gallons again... Lol

Handymans342

Here is my 2 cents, if you don't want to break down get a diesel. You knew that was coming.

diggin2day1

I just got back from the boat... Checked and I'm hooked to the port side fuel pick up(not sure if there's a standard to which side is genset or engine). How Do I check the fuel valve or anti siphon valve? And while I'm asking a ton of rookie questions... Can you recommend a good sealant to use? Thank you for all the help!!!

Dream_Inn

& I know it goes without saying, but when messing with fuel, please caution on the safe side.  Make sure there is no fuel anywhere in the bilge and you seal the line completely.  & give good time for any vapors to dissipate.  There was an incident this past weekend at the fuel dock in Spring Cove (we were there a week ago) and 10 people went to the hospital after an explosion at the fuel dock.  Good luck & I'm sure you'll get this one figured out!

diggin2day1

Thank you Dream_Inn... Will do!