Engine starts and stops after emergency shutoff got hit

[viper1216]

Hey guys,

2004 Maxum with a 2010 Mercruiser 3.0. Took the boat out today. Started and backed off from the trailer and purred like a kitten, Docked it to park the truck, shut it down. Got back in, started right up. Backed away from the dock and accidentally hit the emergency shutdown for when the operator is ejected. Popped the button back up and started. It fired up for about 3 seconds and then died. I can get it to start if I have in neutral and throttle up a bit...it will rev up to about 2k before shutting down again after a couple of seconds. Paddled in, and trailered home, and still doing the same thing (which is great for diag purposes). I'm wondering if the switch is purely coincidental and there is something else going on with it. Thinking if it was the switch, it wouldn't fire at all, but who knows. Boat went out once this year beginning of April and ran great. Filled tank at that time and added quick silver fuel treatment. Added another 5 gallons of fresh fuel today. Any advice greatly appreciated!!

Thanks
Dave

 

[fhhuber]

Good possibility you need to check the little split ring that holds the kill switch enabling the engine to run for cracking. That could lead to it being intermittent and its cheap to replace.

I always look for the cheap fix first.

Next open the panel and jumper the switch temporarily to verify if that is the issue. (next cheapest fix and easy to check)
Note that your switch may be one of 2 types (not sure which for you) Some ground the ignition to kill and some open to kill, breaking the ignition circuit.
The ones that ground to kill you just pull a wire from the switch and you disabled the kill.
The ones that open the circuit to kill you jumper (short) the wires to prevent it from killing the engine.

DO NOT MAKE THIS THE NORMAL MODE OF OPERATION... just trying to find the problem.

The switch is just a few bucks.

Other potential issues include a hole in the fuel line causing you to draw air or a fuel line being plugged or carb issues... and a bunch more.

 

[viper1216]

Ok, trying to get the switch out to test. Is there a way to get that switch out of the remote control assembly? Mine is basically a switch that goes up and down and has a loop that goes over it that when pulled lowers it to the off position, thereby killing the motor. There's no room for me to get behind and see the connections, so I am trying to pull the switch out to get access. I got it pop out about an inch but that's it.

 

[thumpar]

Sounds like a commander control. You hold the throttle only button at the center of the handle and push the throttle all the way forward. You can then take the button out and get to the screw to remove the handle and then remove the plate from there.

 

[alldodge]

Is this motor an MPI model?
If so can you keep it running if it stays reved up, but dies when it idles back down?

 

[viper1216]

I think it is a commander. I'll try to snap a picture of it. It looked like the kill just sort of popped in, I attempted to just pry it out, but thinking now that maybe that wasn't it. Would I need to take the whole remote control apart just to get the switch out? AllDodge....not sure if its MPI...but it will not stay running even when reved up....it goes to about 2k and then dies...

 

[thumpar]

Does it have a carb or is it fuel injected. That would tell you if it is an MPI or not. My guess would be not. There are not a lot of 3.0 MPIs out there.

 

[alldodge]

OK, then it's not the IAC
The kill switch just breaks the 12V going to the motor and all gauges (purple wire). Don't take the switch out right now, go behind the helm and find the ignition switch. Find the purple wire coming off the switch and then find another purple wire on one of the gauges. Put a jumper between these two points.

 

[viper1216]

**Update** If I didn't need a switch, I need one now. Kinda mangled it getting out. I cut the 2 wires off the back and spliced them together. Boat starts, and I can keep it at idle and ok. If I bring throttle up reeaaaly slow I can get it to about 1500 or so, but it feels like it is skipping. If I bring above 1/4 throttle, it will stall completely again. Thinking it probably wasn't the switch and was coincidental. oh well...

AllDodge, didn't see your comment until I had already had the switch out. And yes it is carburated.

 

[thumpar]

Is the fuel new this year? If you have a fuel water separator take it off and put the contents into a glass jar and see if it is just fuel.

 

[alldodge]

Could use a serial number

 

[viper1216]

Yup, new fuel. Filled it beginning of April. Is it possible the choke is sticking or something? I'm assuming it's electric. Is there anything I can look at in the carb throat while its running to know if the choke is not stuck open? I also read something about the anti siphoning valve....the fuel water separator has a drain on the bottom. I had opened that up about a month ago and drained it out, so assuming that would have grabbed any water in there.

 

[viper1216]

SN# 1A612268

 

[alldodge]

Boat starts, and I can keep it at idle and ok.

If this means that it will idle ok and will not die, correct?

If I bring throttle up reeaaaly slow I can get it to about 1500 or so, but it feels like it is skipping. If I bring above 1/4 throttle, it will stall completely again. ...
.

Only when you increase the throttle?

 

[viper1216]

Actually...won't idle now...will stay running if i keep pumping the throttle, but as soon as i leave in one spot it will die. Cleaned the carb filter out...there was a,little debris in there, and am running to get a new fuel pump filter now.

 

[alldodge]

running to get a new fuel pump filter now.

Sounds like a good plan, would be good to check pressure prior, but is really leaning that way

 

[thumpar]

You may want to rebuild the carb too. When you push the accelerator is activates the accelerator pump to push fuel in. There could be a clog in some passages of the carb. The rebuild kits are cheap.

 

[viper1216]

**Next update**....replaced the Carb filter, Fuel pump filter,and anti-siphon valve.same issue. Starts up and dies. I unconnected the 2 wires for the switch and cranked it for a bit....then reconnected, and it started and ran at a good smotth idle for about 20 seconds or so before sputtering and dying. I did it again with the same results. So what I think is happening, by cranking with the switch off, I am just pumping fuel into the carb, then connecting again and firing up and running on the extra gas in there before using it up and dying. So that tells me fuel supply issue. I tried to get a pressure test, but my gauge doesn't have the right connections to test this system Any thoughts on next steps?

 

[thumpar]

Do your gauges work when the switch is connected again?

 

[alldodge]

As before, good plan to replace the pump but would be best to test before.

Your motor has two circuits which turns on the fuel pump, first turns it on while cranking the motor. During the cranking process the oil pressure switch is bypassed. After the motor starts, oil pressure increases and closes the switch which then feeds the fuel pump during the motor running time. If the wire going to the switch or the switch goes bad, the fuel pump will stop.

Note this is a V6 but wiring is the same. The yel/red wire feeds the pump during cranking. Oil pressure switch 5 closes and continues to feed power to the pump.
Find the oil pressure switch and jump the contacts

So far as checking pressure, just need a $20 vacuum fuel pump pressure tester and a tee. Disconnect the fuel line at the carb and install a tee. Should be 4 to 7 pis