2020 150hp possible fuel related issue

[pittpete]

4th time out after purchasing boat with 2020 150hp with 260 hrs and full tank of fuel.
Previous owner never knew he had a fuel water seperator but always rtreated with marine stabil.
I replaced it before going out on my 4th trip.
I cruised around for around an hour+ between 4-4500 RPMs.
Slowed down to around 3000 RPMs while returning and the engine hesitated when I throttled back up.
Kept it at 3000 for a few minutes and tried again and she hesitated.
Kept it at 3000 while limping home for sround 10 minutes or so.
Tried one more time to accelerate before entering marina and she was fine.
Sound like water in fuel or a restriction that some how passed through?
Down to half tank of fuel and no alarms on dash?
Thanks

 

[nola mike]

Could be a lot of things. How old is the gas? Stabil isn't magic. Did you check the filter when you changed it? Might want to take another look. Running off a fresh portable tank is always pretty high on initial troubleshooting steps.

 

[pittpete]

Purchased it 2 weeks ago.
Im sure theres some of last years fuel mixed with new since the guy didnt take it out much this year.
The old separator filter contents didnt look terrible when I poured it into a clear container.
Should I pull the new filter if it happens again?
Thanks for the suggestion on the portable fuel tank.
New to 4 strokes

 

[airshot]

Didn't look terrible....? Any concern at all should have been a call for further testing. As you noticed, walking back to the dock after your motor quits is not a viable choice. Your safest bet is to pump out the fuel tank and check for water which be be near the bottom. Another option is pull the water seporator filter and see how much water is in there. If you not sure, pour a small amount off and see if it burns. I have saw so much water in fuel that it would not burn at all. Saving a tank of fuel is not worth the potential damage to your motor. Pay very close attention where you buy your fuel, in most cases, the fuel your buying is not good as many stations do not properly test and maintain their underground tanks. Fuel needs to be treated before it is contaminated not after.

 

[pittpete]

What I meant by didnt look terrible is I dumped the contents of the fuel separator into a container. It looked clean with no particles in it. I let it sit for half an hour and saw no separation in the container.
I appreciate your response.
My engine didnt quit, it hesitated at 3000 rpms twice after running for over an hour.
Im going back tomorrow for further testing.
I will update in hopes my post can help someone in the future

 

[jlh3rd]

what color is your fuel line? If it's grey, replace it.

 

[dingbat]

Make and model of outboard?
Most modern outboards have fuel moisture sensing to alarm for water in the fuel

Ok, let step back a bit….the motor ran well up until the time you changed the fuel filter. Now the motor hesitates upon acceleration?

If you put the two together, the obvious concern would be a vacuum leak given the problems manifests upon acceleration. You need to go back and revisit your filter installation.

 

[pittpete]

No grey fuel line.
This setup doesnt have the sensor for water in fuel.
The motor ran fine after I had changed the water separator. Cruised around for over an hour and hesitated much later returning to the marina.
Took it out today and ran fine at all RPMs.
Had plenty of 2 strokes over the years but this is my first 4 stroke.
Is it possible a particle or something clogged up an injector and momentarily caused my issue?

 

[Jeff J]

This kind of reminds me of an issue we had on a 150 EFI a few years ago. It took someone really good with the diagnostic computer to identify the throttle position sensor as the culprit. He tried to walk me through the numbers and their relationships on the screen but I wasn’t tracking any of it.

 

[jlh3rd]

well....after yesterday, I'm sympathizing with you and looking for answers again myself.
This is a 2021 Merc. 115hp CT, purchased new.
I thought I had solved my issue.
Yesterday, it sputtered again running about 4000 rpm. Not a good feeling single engine on the Bay at 7 pm 45 minutes from my slip.
Early last year I traced a sputter to the corroding section of the feed to the ignition switch.....fixed , I thought.
Then late last year it happened again. So the filter was changed, it did look contaminated. I also added a fuel/water separator, pulled and checked my pickup tube and tank (absolutely clear even after 20 years) and replaced the check valve fitting...new plugs..thought I was good.
Then early this year coming back from Annapolis, it sputtered again. WTF.
So ran it back to the slip at 5-5500 rpms. No sputter.
There was a section of grey fuel line from the motor to the connector at the motor compartment then black fuel line to the tank.
I replaced that. This was in mid May. Been running all summer and no issue,...until yesterday evening. No water showing in my fuel/water separator. And I can't believe THAT filter is plugged...
Ran it at around 5000 rpm back to my slip....no sputter. 280 hours on the motor.
Vapor separator ?.....filter in the injector line?...(there is one, just involved to get to)

I'm all ears.

 

[airshot]

Are there more filters inside the cowling ? Often we change the obvious ones we can see but sometimes their are others inside buried that no one looks at. Just a suggestion here...

 

[Jeff J]

The only fuel filter I can think of on a Mercury 150 EFI isn’t visible. It’s accessible via yellow handle on the right side of the power head. PITA. It uses press-to-connect connections which helps with installation but can be a challenge to disconnect, especially the outlet hose.

 

[jlh3rd]

Are there more filters inside the cowling ? Often we change the obvious ones we can see but sometimes their are others inside buried that no one looks at. Just a suggestion here...

well, just jnside the fuel rail is one, but it's involved to get to. But how can I run 5-5500 rpm and no sputter if filters are the problem.

The only fuel filter I can think of on a Mercury 150 EFI isn’t visible. It’s accessible via yellow handle on the right side of the power head. PITA. It uses press-to-connect connections which helps with installation but can be a challenge to disconnect, especially the outlet hose.

that would be the first go to filter to change, yep.
I bet that 150 does have the fuel rail filter.

 

[Fun Times]

well, just jnside the fuel rail is one, but it's involved to get to. But how can I run 5-5500 rpm and no sputter if filters are the problem.

that would be the first go to filter to change, yep.
I bet that 150 does have the fuel rail filter.

Opps jlh3rd, you'll want to hold off here as at this point, we're not even sure who airshot and Jeff J are answering too as this thread topic is jumping ship here between two questions now... This topic belongs to pittpete and in turn it would be better for you to create your own new thread or we'd be able to move post numbers 10 - 13 for you to get things started.
?