5.0 mpi stalls/dies for a split second

[Cerhai]

New to me boat, is 2005 ebbtide, 5.0 mpi mercruiser with a alpha one drive. Model: 4-m4102lrs Serial number: 0w032048, what I have going on is it shuts off/dies while idaling or slowly driving it restarts and runs fine. But while I'm under way cruising it will shut down for a sec and keep on going like nothing happened. It happens randomly through out the day I can go for an hour with no problems, it seems to happen at about 2500rpms, I've replaced the spark plugs, cap and rotor, battery had the ecm scanned for codes and nothing. if anyone can point me in the right direction that will be helpful. Thanks.

 

[Cerhai]

This is a video of what happens at 23 seconds then again at 28

 

[tpenfield]

Check the lanyard kill switch, if you have got one. That might be getting a bit flakey.

 

[Searay240sd]

Agree with above, also check and clean every ground. When it happens what does the volt gauge do?

 

[alldodge]

Key switch or kill switch, look for loose connection

 

[Bdaviskar]

Hello. I am having the same issue. If you find out what is causing it can you please let us know? I will do the same. . You can see my post that was posted a few days ago.

 

[bman440440]

I did notice that the volts did NOT drop when it happened... so IMO what ever is going on is after the ignition switch... my 1st thought is the kill switch having issues

 

[Cerhai]

Hello. I am having the same issue. If you find out what is causing it can you please let us know? I will do the same. . You can see my post that was posted a few days ago.

Read your post, yep exactly what I'm experiencing. Will keep you updated if I figure it out.

 

[Cerhai]

My mechanic said when he hooked his laptop to pull the codes everything came up like if the ignition switch was turned on, according to him that shouldn't happen until the key was fisicly turned to on position, he thinks I have a bad engine harness.

 

[alldodge]

he thinks I have a bad engine harness.

Before I would even start to look at the harness, there would be all the other little things first. Key switch, Relay, loose connections

 

[Cerhai]

Update: so I replaced the ignition key. And looked over the kill switch. And all grounds that I can find, did the wiggle test on all conections, thing still blips while underway with the alarm, just like the video above. Took it to a different mechanic he hooked up his laptop and went through the entire thing everything looked good other than the tps was giving funny numbers. He told me for sure that's your problem, I replaced the tps and still same thing. One other thing I discovered today at the lake if I put the throttle into neutral and rev the engine the alarm comes on at about 3500 to 4000 rpms and engine dies when throttle is backed off then I have to crank it a for a bit before it starts up again. I have disconnected the battery for the night hoping to reset the ecm, maybe the funny tps numbers are still stored in the ecm and the boat doesn't know there is a new one. Going back out tomorrow 100 plus temps not gonna last long, before we know it it will be snowing.

 

[alldodge]

rev the engine the alarm comes on at about 3500 to 4000 rpms and engine dies

You should have a "in Gear" switch on the shift plate. If not in gear, the ECM will alarm if rpms go above 3500