2004 250hp 4-stroke shutting down randomly

[capsteve]

Ongoing problem where engine shuts off completely while running on plane. It's like the kill switch is pulled. Happens at various rpms. Replaced key/kill switches. Also replaced primer bulb. Also replaced the computer! Engine will start if I get the long tone, but won't start if tone is a short or intermittent beep. Why is this happening? Any suggestions would be most welcome.

[boats.net]

Possible low voltage to engine due to bad battery, battery cables or relay on engine.

[capsteve]

Low voltage

Thanks for the suggestion. Checked the batteries. Two big ones and 3 smaller ones for trolling motor which are tied in for 36v. All seem to be fine. I might have a bad charger though. But load tests were ok.

Got another suggestion that is may be an ignition relay. Is this something that could be causing the engine to quit while running? Is this a common problem? Easy solution?

[noelm007]

check the white wire, it needs to be connected direct to 12V and be clean and tight, tossing parts at motors on a guess or a "sounds like" will see you with an empty wallet and still have a bad motor, do you have a genuine manual?

[capsteve]

White wire

Yes. I've checked this wire and seems to be going to where it should be and with a good connection. I don't have a manual and have been playing the expensive plug and play game for some time now. Suzuki mechanic is checking on ignition relay and crossing my fingers. Thanks for the reply.

[capsteve]

Not ingnition relay

OK, so it's still cutting out after install of new ignition relay. What seems to be occurring is the computer feels hot. So it seems like the computer itself is overheating. I've tried a couple different computers with the same overheat/shutdown result. I'm guessing there must be some sort of sensor that is telling the computer that it's overheating. But what can cause that? And what's the resolution? Please! Anyone?

[capsteve]

Now I need a new computer?

Ok. So here we go again. I'm now being told I need a new EMM (computer) and/or a new harness. Seems the EMM is overheating thus shutting down the engine. But no one is sure this is the cure to the cause. So plucking down $1600 for a new EMM that might work isn't very reassuring. And then more for a harness still without a guarantee it will fix it. Can't believe this hasn't happened to many other people before. Am I the only one this has happened to? Going for a second opinion but this is the word from Suzuki central so I doubt I'm going to get different answers.

[capsteve]

EMM solution

So just a follow up on my '04 250 4 stroke. It was cutting off unexpectedly and without reason. It seems that there was an older version of the EMM, or computer, installed somehow and was shutting the engine down. Finally took a chance and bought a new EMM and the engine has been running without issue ever since. Thanks for all the input.

[Chippy83]

Capsteve.
I have a 250 doing the exact thing. Few questions if u don't mind.
Would it cut out randomly, some times after 10 miles or could be even longer/ shorter ?
Was there a fuel smell after cut out?
Was the start light / beeper playing up cutting in and out while it was broken down? Almost like a bad earth reaction.
Was there no fault codes showing on Suzuki's system ?

[capsteve]

Yes, it would cut out randomly. Sometimes it was perfectly fine after a long run (45 min.) and then after initial start up it would cut out just after getting on plane. I would get a beeping sound as the motor would cut out. No codes that I'm aware of though. Hope that helps.

[artdf175]

Did you really check the "white wire" connectors?
I had the connection off the battery terminal go bad.. corroded on the inside of the connector.. looked perfect on the outside..
any disruption in the power to the white wire that feeds the ignition switch that then powers the ECU will kill engine..
first thing to do is to cut that connector out and replace it with a good water proof one..
Art..

[capsteve]

Yes, the white wire was in good condition as far as I could tell. Thanks for that info though.
I ran this engine for another year and finally made a switch earlier this year. I've hung a 2014 200hp 4 stroke (white cover) and so far so good. Pretty surprised that the same prop on the 250 works with the new 200 and I don't seem to miss the extra horsepower. Still keeping it between 3500-4200rpm which cruises somewhere around 32-37mph.
Knock on wood.