'23 Merc 15hp EFI alarm

[Mechmagcn]

We have a fleet of rentals at the state park where I work, all running 15hp Mercurys. Most are older, but we have 2, 2023 15hp EFI motors.
Both of the new motors are having the same trouble. They start great, idle, and run wide open . It's when you throttle down that the alarm comes on and you have to kill it and restart before it will run above an idle again. This only happens if you throttle it down slowly, if you drop to an idle fast it never happens.
Talked to the selling dealer and they tell me to bring them in and they'll work em in, you know, maybe in a month.
I've tried different gas tanks with the same results. Water pump is pissing a good stream and oil level is on the full mark. I doubt that either motor has run 5 gallons of gas, which is true non-ethanol. I'm at a loss, really hate to lose the revenue of two boats for the remainder of the season.
Any help will be greatly appreciated, Jeff

 

[alldodge]

Doing your line of work I would strongly suggest getting Diacom software from Rinda. Just to many sensors to take a WAG at it

 

[QBhoy]

Fairly sensitive to oil level, these things. Tell us more around the idea of the oil being to the full mark. Have a wee check that she’s not too full, if you are referring to a site glass indicator

 

[Mechmagcn]

Fairly sensitive to oil level, these things. Tell us more around the idea of the oil being to the full mark. Have a wee check that she’s not too full, if you are referring to a site glass indicator

With the motor level the oil is on the full mark of the dipstick. Do you think that it's actually overfilled? Not sure how this would cause the symptoms I'm having.

 

[Mechmagcn]

Doing your line of work I would strongly suggest getting Diacom software from Rinda. Just to many sensors to take a WAG at it

I'll run that by my superintendent, doubt the state will go for it.

 

[flyingscott]

Aren't they under warranty?

 

[Mechmagcn]

Aren't they under warranty?

They are, but the dealer is backed up, maybe get to it next month.

 

[Mechmagcn]

Fairly sensitive to oil level, these things. Tell us more around the idea of the oil being to the full mark. Have a wee check that she’s not too full, if you are referring to a site glass indicator

You sir win the prize.
In checking closer the oil on one motor was approximately 1/4" above the full mark on the dipstick. I drained about 6oz. out and so far it has run flawlessly.
The other motor hasn't had problems the last two rentals, probably used just enough oil to get to that sweet level.

 

[QBhoy]

You sir win the prize.
In checking closer the oil on one motor was approximately 1/4" above the full mark on the dipstick. I drained about 6oz. out and so far it has run flawlessly.
The other motor hasn't had problems the last two rentals, probably used just enough oil to get to that sweet level.

Excellent. Glad she’s sorted for you. Was only aware of this perhaps being the issue, from a similar experience with a slightly smaller modern merc. All the best

 

[Mechmagcn]

Excellent. Glad she’s sorted for you. Was only aware of this perhaps being the issue, from a similar experience with a slightly smaller modern merc. All the best

I'm still curious as to why the overfill causes this problem, any ideas?

 

[QBhoy]

I'm still curious as to why the overfill causes this problem, any ideas?

It can be common to have too much oil in there, because the oil can get added to or diluted with unburnt fuel…poor combustion, ignition or varying temperature circumstances influence such a result. Oil gets very thin and can then alarm with low oil pressure perhaps. Not to mention a couple of other reasons too