Pair of 2007 525efi flop at same time
 

So, was out for a spin yesterday, boat ran great, then found a spot to anchor off for 1.5hrs. TX temp was 95. Anchor up, idling out, past the markers, throttle down, and about 3000 rpm I hear a pop or click, and both engines nearly die. I pulled back throttle and shut them off. Tried to restart, wouldn't. Would crank, sputter, die. Both engines identical issue. Wonder if vapor lock, over and hour later, same. Got towed in. 85 gallons of fuel on board from March with Chevron Marine stabilizer in.

This morning I put in 12 gallons fresh fuel, back to ramp, once primed and started,, both engines idling fine. Smartcraft showing NO codes. Electric fuel pump working when key turned, etc hear it run. All looks and seems normal. Fuel psi at idle is 40psi and 43psi.

Fuel/water separator was changed Aug 2018, 35hrs ago to today. Will change those agin before next time out. Fuel Filter element is due in 9 more hours when I hit 200hrs. Mechanical Fuel pump fluid changed often, last done Sept 2020, 16 engine hrs ago.

Seems since both engines acted the same, had to be a common source, ie incoming fuel.

Other thoughts???

next time when anchoring leave the hatch up a couple feet, I think you had heat soak V lock

I know you said you had fuel stabilizer in but...sounds an awful lot like phase separation in ethanol blended fuel...? I mean for BOTH engines to experience essentially the same failure at the same time?

Your engines would love you if you changed the water separator and filters annually - cuts down on a lot of issues and filters/services should be based on # of hours or "x" months in the same year.

Agree VL

Thank you all. Merc Racing said same about annual water fuel separator change. Also, when I pull the current ones off, pour into a jar and see how much of each separates out....

Will keep you guys posted...

Replace fuel water separators at the start of EVERY season.

Once I pull the fuel/water separators off, if I find too much water to be the case, what have others done (besides drain the enter tank somehow), to help remedy? I have about 90 gallons from March in there, and 10 gallons from yesterday, for a total of 100 gallons in the tank today.

Thx

You can buy a cheap/small Holley fuel pump from any typical auto parts store. Disconnect the fuel line from the tank heading toward the motor/FW separator, and you can pump the fuel out of the boat into cans, your cars, or a 55 gallon drum. It's not fast, but it works well.

If 85 gallons of fuel from March of this year with stabilizer is giving you issues (separation, too much water, or whatever) I'd be totally surprised.
I'm doubtful there's any issues with the fuel.

Thanks Cheech, and like I said, it fired up and idled on the trailer yesterday fine. Im not real confident in it for the next run around the lake, but is an odd matter. If fuel isnt bad, mechanical fuel pump working, F/W separator doesnt prove to be full of water, PSI reads fine on SmartCraft, is it then a regulator or something else fuel deliver system that could be the matter?

Im not too savvy in all this, so pardon my elementary approach.

Thx
Ian

I should of put in prior post, I'm with F-2, vapor lock for some reason.

Very well could have been vapor lock. The more I read about that, it fits my symptoms and outcome to a T! Now to take steps as mentioned herein to try and avoid in the future!

30-40 min after you shut the boat off is when it gets the hottest, with no fresh water to cool things, hence heat soak, venting the hatch helps getting heat out and air in

If it's vapor lock on the EFI Merc's, do the following.... it worked for me quite a few times with fuel left over in the tanks leaving TX and going to FL, as well as vapor lock:

1. Push throttle all the way forward.
2. Turn key on, let engine prime, but do not start the engine, and then turn key off.
3. Repeat #2 at a minimum of 10-12 times.
4. With throttle still pinned, repeat #2 but try to start engine (it won't start), keeping the ignition button/switch on (starter trying to start the boat) until you hear the engine gargle and try to start.
5. If engine does not gargle and try to start after 15-20 seconds, repeat #2 - #4 (I never had to do this process more than twice).
6. Once it gargles and tries to start, let go of ignition button / switch, pull the throttles back to idle position, turn key off, and start the boat as you normally would.
7. Repeat process for other motors. If you have an OL, which only has one ignition switch, let the first motor run for a bit (at idle), shut off the engine and then repeat for the other engine(s).


*** To prevent this (again, info from Bud), prior to shutting off your engines, let them idle for a couple minutes first.

Hope this helps.

Fun fact: I saw a certain Cig owner at Gilberts in Key Largo who was cracking a fuel line, attempting to release his vapor lock. Out of curiosity, I asked him what he was doing. Needless to say.... he was a bit peeved when I helped him start the boat.

Fun fact #2: The OL comment from above.... I was again trying to get off the dock at Gilberts on different run and the OL guy tied on the outside was vapor locked. I was tied to the dock in the same row. Walked across the boats that were waiting on him to get his started and told him what to do. Needless to say.... the "I'm an upstate guy and my mechanic knows exactly what he's doin'" wasn't interested in a Texan helping him out. So... after threatening to cut his lines and let him figure his problems out in the middle of the channel, he let me start his boat. Took about 2 minutes. His response to his mechanic (with a look on his face) was... wh thu fk gumba? LOL

Re: water in tanks....... run the boat at idle around the lake. Pull the filters every 4-5 minutes and empty them into a suitable bucket, etc... Bring a fuel can and an extra pair of filters (for quicker changing). Fill the filter before screwing it back into the engine sometimes helps, if the engine if finnicky about starting with it empty.

....oh, and yes.... change both the spin-off and in-line often. :bestwishes:

Don't get why some dumb A would crack a fuel line when there is a perfectly good shrader valve, but reality doesn't happen in many places

Agree, if you open the hatch, run the blower will help cool things and can stop VL

I had VL and fixed mine by moving the returning fuel filter and moved it to return to tank. My return came from the fuel rail and not the cool fuel Reg as in pic below. Eddie Young did the fix

A easy fix "when it happens", is need a small screw driver, rag and safety glasses. Remove cap off shrader valve, turn key ON. Place rag over valve and use screw driver to press in on valve. Once air is out and you get fuel, replace cap and fire it up.


https://cimg5.ibsrv.net/gimg/www.off...ccbc77371e.jpg

Wow, wow, wow!!!! Thank you so much for the intel and tips!!!

I'm going to print this thread and keep on the boat. I've chatted with some of the best damn folks via this forum.

Very much appreciated!
ian

Quick update:

So, changed the Fuel Water separators, captured the fuel in a jar, and let sit for the weekend, not a visible drop of water in the fuel, so thats good news..

So,, I take it to ramp, start both engines,, only getting half the recommended 40 fuel psi. After about 5 minutes, both engines sputter out like run out of gas. So, back to the house and I change the fuel filter element. What a job getting the top off (gonna get a tool fabricated to come in from top and spin off). Was only able to get stbd done, port side canister had to be fuly removed and breaker bar used to break the seal and spin cap off. Stbd was cranky, had to prime a bit, but got her started and ran great on trailer at ramp. 40psi fuel pressure.

Im wondering, could all this problem boil down to severely clogged fuel filters? They were damn dirty compared to new. And both engines drink the same fuel, single tank, separate lines, so maybe both got clogged?

Any restrictions/blockage they starve (add 95* weather and you complicate the issue with added symptoms like VL..)

.....As you said they are drinking from the same tank. Hopefully the contamination is limited to the filters and not clogging injectors(which would involve removing and sending out for professional cleaning)

The 525 isn't supposed to vapor lock. The electric fuel pump combined with the mechanical pump is supposed to prevent that per my understanding.

Yes

Many people forget about the fuel filter by the rail, have seen some engines with the ORIGINAL still installed 15 yrs later. Owners change the fuel/water separator spin on every season and think that's all that is needed.

Well, I'll take it on the chin and hope thats all that this issue boils down to. I was well aware of that filter, didn't want to scratch up the blue cap as I ended up doing (going to have a T like tool made for next time), manual does say each 100hrs or at recommission, since last changed Aug 2014, I've put on 92hrs. I know, damn sad and deserving of a separate thread! Lol!

I never knew about that filter! I guess I'm running the original with 450 hours! I will definitely look into this...

Just a quick update, finally got a new port fuel filter body installed after it had to be removed to remove the fuel filter cap. What a bear to get it all back together and in bolted up! Threading in the fuel line from the bottom was unreal...

Anyway, both engines back up and running strong!!! Burped out some air in the fuel lines on first high speed pass, but both strong and responsive now. May never know of ai had vapor lock or clogged filters or both, but now have the tools to change those filters more frequently!

I recommend getting a 7/8" crows foot wrench, 10" extension, and drive (to do the cap removal from the top) along with a 7/8" open end wrench on bottom of filter housing (block the wrench from spinning counter clockwise) to ensure it doesn't spin on you.

Enjoy!

I would certainly say that you had Vapor Lock. The hot weather combined with the fact that the fuel was from March. That was probably still a winter blend of fuel. It has a MUCH lower boiling point so that it burns better in colder weather. It also boils MUCH sooner and at a lower temp.

Thanks for the tip. My 502MPIs, specifically the stbd side gives me vapor lock issues when temps approach the 90's. I run blowers non-stop, let engines idle 5-10 minustes before shutting down and always crack the hatch when parked. Still vaporlocks from time to time. I do attempt to prime as you explain, but not with throttles pinned. I will try it next time and report back.

Bad news, im being towed back in as I type. New fuel filters, good gas, boat was running great today for several hours, anchored off, started, ran great. Then the last of the day. Go to get on plane, a distinguish hollow metal ping (like excess fuel build up that pops), then both engines flop.

Fuel psi reading half where it should when this happens, and drops in time. Now down to 11psi both engines. Should be at 40psi.

I'm perplexed...

something floating around in the tank?

Some strange reason both motors use same pick up ? If so, $50 there is a hole in the pickup.

Hmm, thats a good point. Same pick up? I know there are two separate lines off the fuel tank. One to each engine. Today wasn't even that hot, ran great for hours of fun, some anchoring, etc. Was end of day, like sunset, when she flopped on me.

Can't see vapor lock this time. And, to lose fuel pressure at same clip, both engines. There was again a distinct hollow metal ping when this happened, like a loud fuse popping or something...It's definitely a common issue, im now thinking commom/shared electrical issue somewhere way upstream..

of note, since the fuel filter changes, I ran her hardly for 20min or so, varying speeds, turned off, back on etc. All was good, so felt more confident to go out today, then this...


Would this pick up be somewhere in the tank?

Tank flexing and making noise ? I’ve heard it several times in cars from bad vents. Loud ! This (bad vent), causes loss of fuel psi too.

edit in: the car tanks where steel. Not sure what aluminum tank would sound like, if it would even make one ? Dunno.

You sure the noise isn’t quick intake backfire ? That would happen when fuel pump psi gets low enough to lean sneeze.

Open the gas cap to see if the vent is plugged .

Quick intake backfire may be a descriptor. Not sure. As for gas cap, no vacuum noise when removed.

As the boat has sat this evening, fuel psi on Smartcraft, ignition on only, both engines have dropped fuel psi. Now sitting around 6psi. 4 hrs ago,, both were around 11. When all was good earlier, both were at that 40psi within specs...

fuel pressure regulators

i would run the boat without gas cap for a day ! This way you can rule out vent problem if that is the case

Run it for a while, stop and open gas cap and listen if air gets sucked in

That’s with engine off. Fuel psi is slowly leaking past fuel pump check ball. Thisvwill not cause psi to drop while running.

Key on, engine off willl only turn fuel pumps on for say 5 seconds.

Ian, did you see my thread "Adventures in 525 fuel filter replacement?" You were right. It was a b*itch but you had me prepared.