99’ 250hp OX66 died but started again ?

Ozz043

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#1
Hi all
During the last couple of fishing trips my stbd engine would “stall” once or twice a trip and at different speeds, without warning. It has happened after I have stopped for a fish for 20 minutes so the engine is still warmish and now I’m moving off to another spot .... it stalls before I accelerate or soon after I reach cruise speed. Once it restarted itself when I was going quicker. If I was going slow I could restart it straight away and it may not do it again for the day, or even 3-4 hrs and many other spots ... today it did it again but the second time it would not start again...I limped home on the port engine and then when safely tied up I removed the cowling and it started up straight away ... ?

I believe it is electrical not fuel as it does not splutter or surge it’s like I just turn the ignition off ..........very sudden

Any ideas ?
 

seasick

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#2
It does sound electrical if it stops so quickly. It can be tough to troubleshoot but the first place to start is the kill switch and ignition switch modules at the helm. Check the connections and wiggle things around to see if you can get the motor to stop. if you can, temporarily swap port for starboard to see if the problem moves.

I forgot to ask, when it doesn't want to restart does the ignition 'horn/alarm' sound?
 
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#3
Sound like a loose connection. Kill switch, ignition module, could simply be a battery wire connection.

I had a suzuki that had a bad crimp on a fuse holder inside the engine. Every few trips when I moved the trim, the engine would cut out and start back up.
In that case, the trim pointed me in a direction to look.
 

seasick

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#4
Depending on how many batteries and how the motors are wired, a bad battery connection may affect both motors and not just one. If you can start and run both motors on one battery only and you still have one motor acting up, it probably isn't a battery cabling issue.
The loose or intermittent fuse is a good possibility but check the kill/ignition system first
 
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seasick

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#6
think about that...
I thought about it and I am not sure that what I meant. I was suggesting that if both battery switches (assuming 2 of them) are set to Battery 1 for example, and only one motor shuts down than the cabling from switches to batteries is OK. Same assumption if both switches set to battery 2. This test won't identify battery cable issues between switch and motor though or a bad switch in general (although the symptoms don't sound like a bad switch)

Than again, I may be totally confused. It's been happening more frequently lately. I am hoping its just the lack of sunshine in the North East.
 
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Bdsp1234

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#7
I had a similar issue with starting, but not while out on the water. Boat would start fine one day, and not the next. This went on for several days then finally boat just stopped running. Poor connection from the battery ground at the motor.
 
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seasick

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#8
I had a similar issue with starting, but not while out on the water. Boat would start fine one day, and not the next. This went on for several days then finally boat just stopped running. Poor connection from the battery ground at the motor.
Did it not do anything or did it crank over but not fire up?
 

seasick

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#10
You are saying that the started would engage for a short time and then just stop working?
Sounds like an electrical issue or a possible defective battery (intermittent bad cell. That would only be possible if there is a dedicated battery for each motor ( and/or switches are not set to BOTH)

The first place to inspect it a tie between the actual battery connections and the battery cable connections at the motor. Disconnect the neg at the batter for that and then remove and inspect the cable connections on the motor.
Keep us updated.
 

Ozz043

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#12
Ok so I was able to get it to play up in the marina.

I fired it up, put it into gear for a few minutes to get it warm, turned off then started again and put into gear for a few more minutes. Stopped and waited ten or so minutes....no go

I have wobbled the wires a bit but I was strapped for time so I couldn’t spend a whole lot there.
I did try both batteries, made no difference
I did try main fuel tank too, made no difference ( I agree that it seems to be electrical)

Will keep at it
 

seasick

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#13
What does No Go mean? Did it do anything like crank over and not fire or did it do nothing?
Did you get any alarm beep at the helm either when you turned the ignition one click to ON or when you turned the key two clicks to crank?
In addition to checking the main power connections at the motor, open the fuse box and remove and re-seat the fuses. I have seen those get a bit corroded and intermittent. You can lightly sand the fuse lugs if they look oxidized.
 

Ozz043

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#14
You’re right seasick I was quite vague with my description.The engine stopped and the alarm sounded, I turned it off and then on again. The alarm beeped and then it cranked over at normal pace but did not fire.

The fuses you are referring to are in the box on the starboard side of the engine I assume, Seasick ?
I shall give that a try.

A mate is coming to help in a couple of days so I can crank the engine and check for sparks at the plugs....
Any ideas if there is a spark ?
 

DennisG01

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#15
Check the kill switch - if it's slightly broken, it may be working sometimes, and not others. If the "V" is cracked, it won't hold the little button out far enough because the two fingers will spread slightly. This may not be the issue - but it is certainly a viable reason.
 
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#16
So I get the sense that the engine has to be warm to show the problem? Would you say that is always the case?
That could be an electronics problem but also just a connection problem.

Man, there are just so many possibilities. I'll throw some ideas out there.

I would disconnect the starboard motor from all battery switches and connect it directly to its own battery.
While I was doing that I would really inspect the condition of the battery to motor cable at both ends and along its length.
look for green ends and for a stiff section of wire along its length.

Then run it that way. That isolates it from all other battery/switch issues.
Just for sh!ts &giggles, since you have isolated the battery....I would measure the voltage at the battery while its running for 13++ volts just to be sure the stator and regulator are ok.

I would disconnect the wire from the kill switch. ( the kill switch makes connection to ground to KILL. If you disconnect it it can't kill.)
edit: if yours is like mine, there is only one kill switch for both motors, so that is not the likely cause

I would inspect closely all connectors on the ECM.
Get some electronics freeze spray (computer duster spray will work in a pinch) and when it acts up, spray the ECM heavily and see if that makes a change in how quickly you can restart.
 
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Fishtales

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#17
Start at the battery and chase every positive and negative wire connection. Ensure they are proper and tight. Go into the engine if you have to. Sounds like a ground wire to me. Are you having any other electrical issues?
 

seasick

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#18
You’re right seasick I was quite vague with my description.The engine stopped and the alarm sounded, I turned it off and then on again. The alarm beeped and then it cranked over at normal pace but did not fire.

The fuses you are referring to are in the box on the starboard side of the engine I assume, Seasick ?
I shall give that a try.

A mate is coming to help in a couple of days so I can crank the engine and check for sparks at the plugs....
Any ideas if there is a spark ?
I would not expect the alarm to sound after the engine shut down unless there was an alarm condition. The problem is that I don't think any specific alarm will cause the motor to shut off. Serious alarms like low oil in the main oil reservoir cause the motor to revert to Safe mode but not shutdown. If the alarm sounded after shutdown but stopped all by itself, I would think that the main juice to the motor OR the feed that signals that the ignition key it on got interrupted.
If your motor normally sounds the alarm when you turn on the ignition, that could explain the alarm you hear when the motor shuts down. It would mean that the motor lost power for a while but then regained it just like it would if you turned the key off and then on
The fuses are I believe on the starboard side under a plastic cover. Your issue does sound electrical but there are so many things that could be at fault. ( the worst case is a bad ECU ) Some motors use the cooling water to cool the ECU. If it overheats it will act up and could get fried.

What you might want to do is the following:
Let us know if the alarm sounds normally when you first turn on the ignition. If it does normally does it stop after a short wait and before you turn the key to START? ( The SX150 do not sound any tone when the key is turned on but I know that other models do, I just don't know which ones)

With the motor running, manually pull the kill clip. Of course the motor will shut down but does the alarm sound and if so does it shut off after a short time ( ignition key is still in ON position)

With the motor off, pull the kill key and try to start the motor. Does it do anything? What if any alarms sound?

I have seen cases of these mysterious electrical issues where wires in the rigging tube had broken and made intermittent contact. Those are really hard to find.
Also remember my suggestion if possible of swapping the port and starboard ignition module connections to see if the problem moves from the current motor to the other. That would tell you that the ignition module/switches have issues. If the problem reoccurs on the same motor, the helm parts are probably good and the problem is farther back.
 

Ozz043

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#19
Thanks to all for your input, a mate and I will spend some time on it tomorrow
For now though...
The kill switch is not connected to the engine as I found that out by mistake some time ago, it starts without the kill switch clip in place.
The alarm sounds when the ignition is turned on and then goes silent when system checks are complete
I think that the alarm comes on after it dies because it’s going through the checks again

It’s funny because I think it’s electrical, to do with ignition but others think it’s fuel related.....none from here have mentioned fuel at all.

I will start with the battery, disconnect and clean the terminals, reconnect.
Check the ignition wires at the helm

One thought I did have ..... it’s right out there....it might be the wires preventing the engine starting whilst in gear ? I did have some issues with gear selection after the recent impeller replacement
 

seasick

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#20
Thanks to all for your input, a mate and I will spend some time on it tomorrow
For now though...
The kill switch is not connected to the engine as I found that out by mistake some time ago, it starts without the kill switch clip in place.
The alarm sounds when the ignition is turned on and then goes silent when system checks are complete
I think that the alarm comes on after it dies because it’s going through the checks again

It’s funny because I think it’s electrical, to do with ignition but others think it’s fuel related.....none from here have mentioned fuel at all.

I will start with the battery, disconnect and clean the terminals, reconnect.
Check the ignition wires at the helm

One thought I did have ..... it’s right out there....it might be the wires preventing the engine starting whilst in gear ? I did have some issues with gear selection after the recent impeller replacement
If the lower unit was installed with the shift level not 'centered' correctly, you might have problems shifting into gear but that would not change where the neutral safety switch gets activated as far as where the throttle/shift level is. The neutral switch is in the helm control. In addition if it were not disengaged for waht ever reason, when you turned the key to start, the alarm would sound.

The kill switch update is important news. . Of course it is dangerous to not have an operational kill switch but more importantly the fact that it has been bypassed tells me there were issues in the past and instead of fixing them, the circuit was bypassed. You need to find out where the circuit was bypassed and check what was done. It is possible that the 'fix' has come loose.

The other info about the alarm sounding and then stopping also tells me that the ignition was disconnected and reconnected. That helps with the diagnosis.

It is natural for folks to think of fuel starvation when a motor dies but they usually don't die abruptly, they may sputter or misfire first. Also note that if it were fuel and the motor dies, when you tried to restart, the motor would crank over. I believe that you stated that sometimes it wouldn't even crank. That's a clear indication of an electrical issue.