A word about changing spark plugs in your outboard....

[fishinwrench]

59 minutes ago, aarchdale@coresleep.com said:

carb for life...lol

That's right 👍 

ECM's / ECU's last as long as the average cell phone or laptop.  So even if the injectors and compressors hold up for awhile....that little brain box that controls everything is gonna puke.   And they never puke when sitting in your driveway, they do it when you're far from your truck & trailer.   

Don't think you can just carry a spare one either......cuz it doesn't work like that.   

It amazes me that they trust them on aircraft too. That's why I'll never board one.  

[MrGiggles]

Oddly enough I've had several vehicles come in with misfires, hard starting, in general running like crap. Pull the plugs and you could just about pass a pencil through the gap, originals with 100k+ miles on them. They last so long people don't really think about them anymore, but they do wear out. It also doesn't help that manufacturers seem to be playing a never-ending game of "where can I hide this where nobody would find it," so changing them is labor intensive. 

I also had a run-in one time with some fake Denso iridiums from Amazon. The electrodes completely eroded within about 3 months time, those plugs should've lasted 50k miles or more. Don't buy parts from Amazon.

I had a commercial pressure washer come in once with a 13hp Honda, would run for about a minute and shut down like clockwork. Went through the fuel system, had good spark when it quit, was just about to pull my hair out when I decided to try a different plug. Fixed, ran like a champ.

[tjm]

10 hours ago, fishinwrench said:

ECM's / ECU's last as long as the average cell phone or laptop.

 So, when an engine comes in with a misfire is the ECM the first thing you replace? injector? what?

 

[Dutch]

11 hours ago, fishinwrench said:

That's right 👍 

ECM's / ECU's last as long as the average cell phone or laptop.  So even if the injectors and compressors hold up for awhile....that little brain box that controls everything is gonna puke.   And they never puke when sitting in your driveway, they do it when you're far from your truck & trailer.   

Where are you getting that data?  I would like to read the research on this as I seem to be in the lucky minority.

[fishinwrench]

1 hour ago, tjm said:

 So, when an engine comes in with a misfire is the ECM the first thing you replace? injector? what?

 

Troubleshooting consists of a Compression test, Ignition & charging system test, Fuel system test......In that order. 

[fishinwrench]

1 hour ago, Dutch said:

Where are you getting that data?  I would like to read the research on this as I seem to be in the lucky minority.

There you go with that term...."data" 🙄 

 

What is the oldest smartphone or laptop you know of, that is still functioning properly?    The circuitry is the same.   

And troubleshooting programs are only 50% accurate.  When the troubleshooting program fails to properly diagnose the problem the ECM/ECU is considered bad.  There's your "data".   So whether the ECM/ECU is TRULY bad or NOT a certified tech is trained to REPLACE IT.     

[tjm]

23 minutes ago, fishinwrench said:

Troubleshooting consists of a Compression test, Ignition & charging system test, Fuel system test......In that order. 

So the plug would be the second thing as the ignition is totally dependent on it functioning? I'm not familiar with boat engines, but have some experience with other internal combustion engines and I don't think I ever saw a charging system failure cause a misfire.  can't really wrap my head around that idea.

[Flysmallie]

42 minutes ago, fishinwrench said:

There you go with that term...."data" 🙄 

 

What is the oldest smartphone or laptop you know of, that is still functioning properly?  

The one that’s in my garage. It’s about 15 years old and has been on for the last 10 or so years. It works as well as it always has. There’s a regular computer that has been running in my office for the last 17 years. 

[fishinwrench]

33 minutes ago, tjm said:

So the plug would be the second thing as the ignition is totally dependent on it functioning? I'm not familiar with boat engines, but have some experience with other internal combustion engines and I don't think I ever saw a charging system failure cause a misfire.  can't really wrap my head around that idea.

Yo, this isn't TECH CORNER here !    98% of the time you guys all hate me, so I should just tell ya to piss-off.....or ignore ya 😅 

But actually a bad plug is suspect only if the engine fails a CYLINDER DROP test.   A cylinder failing a cylinder drop test narrows it down to either a bad plug.....or a failure of that cylinder to receive fuel.   Because you've already established that compression is good and the ignition system is supplying voltage to the spark plug.  

A problem with the charging system can cause a intermittent and/or random misfire (usually at higher speeds).   If disconnecting the 2 big yellow leads coming from the stator eliminates the misfire....then it is caused by the charging system.  If you notice a fluttering tachometer also....during the misfire....then you don't even need to test any further.  The voltage regulator is definitely bad......and it probably damaged the tachometer too.  

I've warned about this on this forum before, if you've been paying attention.   This particular failure is caused by HOOKING UP A BATTERY BACKWARDS....AND THEN TURNING THE KEY ON.    Remember?   🙂

[fishinwrench]

16 minutes ago, Flysmallie said:

The one that’s in my garage. It’s about 15 years old and has been on for the last 10 or so years. It works as well as it always has. There’s a regular computer that has been running in my office for the last 17 years. 

Good for you ! 

They don't all last that long though, do they?

I have to replace my cell phone about every 2-3 years. And my laptop about every 5-6 years.    

A bad ECU/ECM doesn't always mean that the motor won't RUN.....But it does mean that the diagnostic software won't pinpoint an issue when&if one occurs.