F150 in limp mode?

[6x6rrlbull]

I have a 2005 F150 Yamaha 4 stroke with 270 hours. The last time I was on the water the motor started
and ran fine at low speed. I brought the boat up on a plane and ran at 4000 rpm for 5 minutes or so. I felt the motor loose power and headed back to the dock. I could only idle and the motor was running rough. There were no alarms, the oil level was fine and the water pump was working fine. I thought i may have lost a coil so I pulled the plugs and the insulators on plugs 1&3 have some carbon on them but the insulators on plugs 2&4 are pure white. It appears that the coils are ok sine I have a clean and a dirty plug on each coil. Am i in limp mode? Any help would be appreciated.

[rodbolt17]

most lilkely not in limp mode.
does your alarm horn actually work?
to test simply pull the E stop lanyard and crank it.
if the audible sounds the circuits work.
most likely you have fuel system issues.
anything that will place the ECU in "limp" mode will also set the audible alarm.

[TownsendsFJR1300]

Drain the VST, (starboard side, clear plastic hose attached to the bottom) into a CLEAN SMALL container. You can also squeeze the primer bulb to flush more fuel out.

Your looking for any water, PARTICLES, crap.

How old is the fuel, is it ethanol and was stabilized used?

R&R the under cowl fuel filter and again, check for crap, water.

If you've been around engines, also "smell" the fuel. You can
usually tell if it's gone foul or is fresh..

Something to consider is replacing the spark plugs. If original, their due.
I had some higher RPM issues (not the same as yours) and new spark plugs
fixed it..

[6x6rrlbull]

There was a tiny bit of water in the VST tank, maybe 1/10 of an ounce. The gas has been stabilized and smells fine. The alarm works.
I recently had the injectors professionally cleaned and I replaced all the filters. I believe the problem is electrical, when the problem occurred it was like someone flipped a switch and it seems like the motor is running on 2 cylinders. Any help would be appreciated.

Thanks

[pstephens46]

If you have water in VST, you probably have water elsewhere. You may need to drain and clean fuel tank and then work forwards checking line and filters again.

[TownsendsFJR1300]

Agreed there shouldn't be water in there, BUT I wouldn't start draining the entire tank just yet for that very little amount of water.

If you primer pump more fuel thru the VST (valve open and catching it) are you getting any more water?

Any water in the under cowl filter and(if equipped), transom fuel filter?

*If you believe it's electric, ie spark NOT working, invest in a spark tester and run the boat with it hooked up. When it starts acting up, check (a helper wouldn't hurt) and see if your loosing spark. Do all 4 plugs..

[pstephens46]

My concern is the low hours for an 11 year motor. Prob used 100 hours first year and then typically declining use after that. Then the fuel sits for a LONG time. Not getting cycled enough. Just me, but l would only want to deal with this once.....

[TownsendsFJR1300]

My concern is the low hours for an 11 year motor. Prob used 100 hours first year and then typically declining use after that. Then the fuel sits for a LONG time. Not getting cycled enough. Just me, but l would only want to deal with this once.....

Agreed. An easier way would be to run off a 6 gallon tank and see what happens.

Just a side note, With the additives I use(K100, RF), when I drained my tank about a year ago (first time EVER, 1997 tank), I drained thru the reg PU. The approx 35 gallons I got out, NO water, not cloudy and most of it was about 2 years old(non-ethanol).

I drained the fuel as I had a running issue right at 5300 RPM's, breaking up, RPMs dropping. Believing the fuel could be the issue I drained it. New fuel didn't make a difference however, (per the local shop), I changed out the spark plugs (which were original and looked new. new plugs in, hesitation/ issue gone! Runs right up to 5,900 (WOT) every time! Lastly, my neighbor bought the majority of the old fuel and I kept some, which worked fine in his boat/SUV, my mower..And that fuel smelled and looked new with the additives...

I have about 200 hours on this engine (I know....Since 2007) but with a 19 year old tank...

I'd like to hear a bit more info from the OP about use, age of fuel, etc before I drained it personally..

[6x6rrlbull]

It was water

My problem was water related, live and learn. Thanks everyone!

[pstephens46]

Don't know if this OP will see this. I am sure there are other opinions - but stabilized ethanol is not stable....... it is crap. Use Non-ethanol fuel, use stabilizer if you want....

[99yam40]

any fuel system that puts water into filters needs to be have the tank drained and cleaned as there is a lot more water in that tank that the pick tube is not getting out because it is not on the very bottom to keep from picking up the water and crud on the bottom.

add e fuel and any sign of free water in filters is very bad, means the rest of fuel is bad because it has absorbed all of the water it could and the ethanol has been dropped out leaving crap fuel

[TownsendsFJR1300]

The savings of ethonol vs non ethonol when filling is obvious.

Not so obvious is the PROBLEMS later down the road (fuel line disintegration, additional water being absorbed from the air, clogged/varnished up carbs, the list goes on) that'll make you pay up later, down time, etc...

Pay me now or pay me MORE, LATER.....

[pstephens46]

We try to tell people. See em lined up at the gas stations with the boats, all sizes and dollars, pumping that crap into the tanks....."Well Yamaha says its okay in the owners manual!!"

[TownsendsFJR1300]

We try to tell people. See em lined up at the gas stations with the boats, all sizes and dollars, pumping that crap into the tanks....."Well Yamaha says its okay in the owners manual!!"

I was at the mower shop earlier today. On their counter, was the 5 or 6 viles of fuel additives with water and fuel in them. Of course the K100 was one of them with a nail (like the others), inside.

That nail was nice and clean, and NO separation of water.

[99yam40]

Sounds good if you can find non e fuel around where you live.
as luck has it there is a old station that just got new tanks and pumps close to me that put in a Non E tank with pumps, but there has been months when they still did not have any to sell.

I run a 6 gal tank I fill with e fuel and run my boat often. I even take the tank out of the boat when it sits at the house and put it out of the sun in a storage building with the vent on tank closed so it does not breath.
everyone deals with this stuff the best they can