Merc 240 shuts off above 3500rpm

Status
Not open for further replies.
gioakjoe

gioakjoe

Active Member
This weekend I was out using the boat and one of my friends lost there hat I made a sharp turn and the engine cut out during the turn, I thought since I made a sharp turn I stalled the engine like some cars do when they spin out. I turned the boat right back on and drove towards my friends hat and after he got it I pushed the throttle up and the boat died again. Was able to troll back to the boat ramp and put the boat on the trailer no problem but had to go slow. I got no alarms or buzzers, I have a merc monitor and the engine never got above 130 degrees had water pressure and every thing looked normal.

The next day I wanted to make sure nothing was wrong fearing the worst as I have gone threw a rebuild this year I pulled the plugs looking for signs of a blown piston but every thing looked clean. I took the boat to the ramp and ran the boat on the tailor ran fine till I gave it gas and It died again no buzzers no alarms every thing looked like it was running fine.

I saw a thread about the older 240 engines about filters and throttle guardians So is this the best place for me to start on the 2nd gen 240 engine? any other ideas would help please and thank you.
 
Well...............


OK... the EFI boats don't stall, no mater how hard you spin them. I've pushed mine harder than an Islandia should be, (enough to scare myself) and never stalled it.

I guess I would start with putting on fresh filters, and then checking the high pressure fuel at the valve on the vapor tank.

Also... how low is the tank? It's not common, but once in a while, we will see a pick-up with a crack, and the boat will run fine until it hits that spot.


Is your "Mercury Monitor" like one of the smartcraft gauges? If it is... see if there is a code in the ECU.


One last thing... was your bilge fan running when the engine stalled? Are all the vent tubes mounted in the boat? If you get a build up of fuel vapor... sometimes the engine will choke out.
 
OK... the EFI boats don't stall, no mater how hard you spin them. I've pushed mine harder than an Islandia should be, (enough to scare myself) and never stalled it.

Good to know

I guess I would start with putting on fresh filters, and then checking the high pressure fuel at the valve on the vapor tank.

Ill try this

Also... how low is the tank? It's not common, but once in a while, we will see a pick-up with a crack, and the boat will run fine until it hits that spot.

fuel tank was about half full was filled to the top at the start of the day

Is your "Mercury Monitor" like one of the smartcraft gauges? If it is... see if there is a code in the ECU.

yes, and no codes where recorded at any time of the ride

One last thing... was your bilge fan running when the engine stalled? Are all the vent tubes mounted in the boat? If you get a build up of fuel vapor... sometimes the engine will choke out.

Yes, I always run with my Fans on and they have those black vents that come down into the engine compartment, the second day when I took the boat out on the trailer to test it I had the engine bay opened up so couldn't be bad air

my first guess was that it was an engine guardian as it really just kicked in if I tried to go over 3500 rpm ish and boom off but i figured I would get some kind of warning on my merc monitor or a buzzer. I am going to go take another stab at it after work tonight see if I can check those filters.

thanks for the help
 
Nice !! I really wish that my boat had the newer engine in it. I can get the old style smartcraft gauge... but only a few things will work with the old ECU.


Anyway... If your guardian is still hooked up... I would disconnect it. It's not supposed to shut down the engine... but when they go bad... they just do wacky stuff. But I would still make sure you have full pressure on the injection.
 
do you have a picture of the engine guardian? I don't remember seeing it in the dash when I was in there
 
It's just a small black box, with a bunch of wires coming out of it. All the Merc boats have them... but it could have been already removed. Unfortunately, it's not on any of the wiring diagrams. In the Islandia, it's in the helm. In your boat, it may be somewhere else.
 
I am going to my storage Unit to work on the boat after work, how would I disconnect the box if I find it? Is it a harness to unplug or cut a certain wire?
 
This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.
Well took everything off and didn't see the box.... Took the boat out and ran it on the trailor with no problem then took it out and bam died right away

Sent from my XT1254 using Tapatalk
 
If you can find it... just cut the black/yellow wire. But, they are known to go bad, and they just do strange things. SO... most of them are already gone, since they are expensive, and really not needed.

Well... unfortunately... when you get an issue like this... you need to go out with tools. When it dies, then check spark on all cyl's, and check for fuel pressure at the vapor tank.


BUT... I would also pull every plug apart, and check for corrosion. Also, go over every inch of wire, and look for little teeth marks. Mice just love to chew wires.
 
Yea I was out there with the engine on wiggling every wire to see if it would kill the engine. Then I ran a compression test to just make sure. All the plugs came back at about 124psi. I'll get a spark plug tester and test the spark plugs this weekend.

Thanks for the help

Sent from my XT1254 using Tapatalk
 
Status
Not open for further replies.

Similar threads

1800 Challenger 01
2001 Challenger 1800 240 EFI M2 Gen 1 cranks but does not start
Replies
5
Views
757
Tim75
T
1800 Challenger 01
2001 Challenger 1800 240 EFI M2 Gen 1 starts and dies after 2 seconds
Replies
8
Views
884
1800 Challenger 01
1800 Challenger 01
S
Seadoo Islandia Cavitation When Turning
Replies
3
Views
488
Tim75
T
Aquaman1
Engine alarm frustration
Replies
5
Views
549
boboeser
B
D
Instant loss of engine power 2017 GTX S 155
Replies
3
Views
1,849
dbweimar
D
Back
Top