What all does the Ignition Coil do (278000586)

[parkericharda]

I've been having some issues with my Strbd engine on my 1996 Sea Doo Speedster. I've had the issue for years, but only recently has it become a big enough issue to need to diagnose and fix. This boat is old enough now, the dealers won't work on it, and the marinas are generally much more expensive (if they can figure out the issue). Here is what I am experiencing.

1. Sometimes when I go to start it, it will not crank but 1 time, and then when I push the start button again, it gives 1 long beep. I have to then remove the lanyard key and wait 5 seconds, put it back in, and then it starts ok, although it seems to struggle to start cranking, but once it has started, then it's fine and will start.

2. I'll be out running 5-6k rpm or so, and all of a sudden it will drop down and can't get higher than 3k or so. If you give too much more, it then seems like it cavitates or there's just no additional power there... it's strange. Wear rings and impellers look brand new! When I'm running it at home with a hose, it idles at 3k rpm whereas Port engine idles k. So I don't know if it is a rev limiter issue (I don't know where this is even) or if this ignition coil has anything to do with it.

I'm fairly confident this has nothing to do with gas, because this has happened for years, and I run through gas frequently. It doesn't happen ALL the time. The impeller area is also clear.

I switched ignition coils, and the engine seemed to idle lower (like the port one), but not sure that solved the problem completely as I was at home and hard to tell with hose hooked up. Where is the rev limiter and does it have anything to do with the ignition coil, or does that just send spark to the plugs?

Thanks!

 

[Dr Honda]

The CDI produces the high voltage spike for the ignition coil, to produce the "Spark". It also controls the timing.



BUT... assuming the drop in RPM is instant (From 6000, down to 3000)... and couple that with the long beep issue... then I'm guessing you have a neutral safety switch issue. If the boat thinks it's NOT in neutral, it won't start, and give you a long beep. THEN... after it's running... and it thinks it IS in neutral... there is a revlimiter that limits the engines to 3500 rpm.



SO... I'd say you have a bad switch.

 

[parkericharda]

I wrote a whole reply to this and poof it was gone. So let me try again.

Does the CDI perform any other functions? Were you implying by your reply that it is highly unlikely to be the cause of my problem?

To clarify on the beeps, that only happens when it fails to turn over, and it's the subsequent time. It also only happens when it's been sitting for a week or 2. For example, it had been sitting for 2 weeks, turned over once, then died (like it wasn't getting enough power or the power was cut). Then it beeps the subsequent time, pull the lanyard, reset and it turns right over and starts just fine. After that, the subsequent starts are fine as well.

Where is the rev limiter... is that part of the CDI or something else? I've never been able to determine this.

Does the CDI control idle speed? When I switched CDIs (port and strbd) yesterday it seemed to idle lower like the other engine, which is why I suspected the CDI.

Are there codes that a dealer could hook up and see exactly what's wrong, or not like a car? I don't have a dealer locally, which is why I don't just pop on over.

Thanks for your help.
Richard

 

[Dr Honda]

On the 720 engine...

The CDI is built into the coil pack. If you have a bad CDI... then yes, I guess, there can be some changes in idle RPM. But generally it doesn't happen like that. The CDI doesn't directly control the idle speed... but if it's running a little more timing... that would show up as a higher idle.

NO... on the 720 engine... there isn't any "Dealer Adjustments" available via the CDI or MPEM. (There is with the 800 engine )

The rev-limiter is built into the MPEM.


Your description of the beep now, sounds more like a weak battery. While cranking, the voltage sags, and then the MPEM resets.




Regardless... I would still check the neutral switch.

 

[parkericharda]

Excuse my ignorance... what is the MPEM? Do you think the rev limiter could have anything to do with the problem?

 

[parkericharda]

Today I took the boat out and it ran fine for 3 hours... no problems whatsoever! Now I'm really confused!

 

[Dr Honda]

Today I took the boat out and it ran fine for 3 hours... no problems whatsoever! Now I'm really confused!

With boats... sometimes that's just how it is. You get a loose or corroded connections... and simply unplugging, checking, and putting things back together is enough to make it work again.


As far as your question of... "What's the MPEM?"... it's the main computer that runs the boat. It will be mounted in the gray box in the engine compartment. FYI... it's VERY sensitive to over-voltage. So NEVER jump start your boat !!!!! or try to crank it with a charger hooked to the battery. If you roast it... there is a slim chance you will find a replacement. And if you do... it will be +$900.

 

[parkericharda]

With boats... sometimes that's just how it is. You get a loose or corroded connections... and simply unplugging, checking, and putting things back together is enough to make it work again.


As far as your question of... "What's the MPEM?"... it's the main computer that runs the boat. It will be mounted in the gray box in the engine compartment. FYI... it's VERY sensitive to over-voltage. So NEVER jump start your boat !!!!! or try to crank it with a charger hooked to the battery. If you roast it... there is a slim chance you will find a replacement. And if you do... it will be +$900.

Guess I just have to keep unplugging and plugging stuff in. Ha! It's a little disconcerting given that I'm trying to sell the boat... definitely have to say "all sales are final" and try not to feel bad if the buyer comes back and says your boat stinks.

 

[ialonso]

The long beep behavior matches the neutral switch. Next time it happens. try jiggling the FNR lever. To see the behavior (as it should work) try to start the boat in forward, and it should beep with a sequence (long beep maybe, can't recall) then you set the FNR lever to neutral and it beeps again to alert you that you are now in neutral. trying to start the boat now should cause it to crank.

Try doing that and see if the behavior matches

 

[parkericharda]

Thanks, but I'm confident this has nothing to do with it. The engine will turn over a couple times, and then die (just the strbd.)... then, if I don't pull the lanyard first, it does the long beep until I replace the lanyard. If it was the neutral switch, it wouldn't even turn over the first time. I appreciate the thought, and you are correct... just not my problem I don't think.

 

[ialonso]

If it was the coil and you were running on only one cylinder intermittently when you drop to 3K RPM that would explain both things. I have mostly heard of coils either working or not. however the spark plug boots/wires/covers I have seen become deteriorated enough that may impact performance. Did you by any chance tug a little to make sure the spark plug boots seemed well attached? (Grasping at straws) Best of luck!

 

[Waterluvr]

Thanks, but I'm confident this has nothing to do with it. The engine will turn over a couple times, and then die (just the strbd.)... then, if I don't pull the lanyard first, it does the long beep until I replace the lanyard. If it was the neutral switch, it wouldn't even turn over the first time. I appreciate the thought, and you are correct... just not my problem I don't think.

When I test for this particular issue on a Speedster with your MPEM I tie the boat to the dock, remove the rev limiter/stop wire(s) from the suspect engine coil(s) and install a separate ground wire with a push button momentary switch so I can stop the engine as needed.

If the problem goes away and the engine runs with the rev limiter/stop wire off the MPEM has failed on that circuit and or the start/stop button has an intermittent failure causing it to ground without being pushed.