Sportjet 90 - lost spark

My_Jet90

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I have a new to me, used 1995 Force Sportjet 90 jetboat that stranded me on the 3rd time out. I have no spark on #1 (only cyl I checked). I've read the forms and tried the basics.

My question is related to I have the Clymer repair manual but it references the original black stator electronics. This motor was converted over to the red stator by the previous owner. Does anyone have the correct wiring diagram and troubleshooting steps. I've read the readings are different and am find some conflicting information .

While testing with the manual I have, I disconnected all billet plugs and did an inspection on all writes. After re-assembly, the key would not activate the starter. Then when leaving the key in the on position and jumping the starter...I had spark. After that, the key worked but then no spark.

The previous owner game me lots of new spare parts that included a new key switch (for boats) and I did install that. No luck. Then one other time while debugging and starting I had observed no spark, but then the boat started on the other 2 cyl and then spark on #1. I was surprised it started and turned if off immediately.

I have not been able to get spark since. The battery is good and it spins over fast. It's been in my shop for a few weeks now and I've been working on it here and there.

Any correct RED stator information would be appreciated. I am also using a simple digital ohm meter.

Thanks for any information
 

kend301

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Re: Sportjet 90 - lost spark

See the first post in the PWC section (Sport Jet Basics) and post results , we can get started when I have some info to work with .
 

My_Jet90

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Re: Sportjet 90 - lost spark

Thanks...I've got the red stator.

Volts read 12.95 and cranks over as fast as it normally does

Stator green/white to white/green reads 680 ohms

Trigger reads
Brown: 1208 ohms
Purple: 1063
White: 1208

I'm also looking for a wiring diagram. I can identify the 3 coils and the voltage regulator. That still leaves 2 boxes. One I think is the switchbox with lots of wires coming out of the side and a blue wire from one end.

The other mystery box has a black/yellow, purple, brown and black wire only. Is this my switchbox? The brown wire splits into 2 billets and I'm not sure where to reconnect these up. That is why I'm looking for the RED stator wiring diagram.

And I think the rev limiter has been removed as I see nothing where it shoudl be bolted on the starter side of the engine.

Thanks again for any light you can shed.
 
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kend301

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Re: Sportjet 90 - lost spark

Black / yellow wire is the kill circuit , can you post a pic of the "mystery box" could be the rev limiter as purple and brown run to it , Unplug the black /yellow from the mystery box and check spark , If not reOHM the trigger , purple is out of spec . BUt I want to see the BOX before I recommend trigger replacement .
 

My_Jet90

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Re: Sportjet 90 - lost spark

I tested for spark with the mystery box (Rev limiter) wires unplugged. Black wire to the ground was removed. Purple was still connected, Black/yellow was unplugged and I don't know where the 2 brown wires go. The box has a single brown wire comming out of it and then splits into 2 brown (one female and one male connector). LOL...I should plug them to each other...lol!


Attached are a couple of pictures. The box on the right must be my rev limiter. The other picture shows the brown wire split.


Does the trigger have a wire for each coil?

I uploaded 2 pictures but not sure where they are. I'll email a copy to you just in case they didn't make it here. The PN# on the mystery box is: x21889 A48 xx75
 

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kend301

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Re: Sportjet 90 - lost spark

Looking at your first pic , Left to right is ,
Coils , above them the box if the voltage regulator
Next big black box , Switchbox with the red stator adapter on top
last box is the rev limiter
The 2 red wires do not go together one should plug into a harness and tape the other one up .

ORDER a trigger it is bad if you need part numbers they are :
Mercury : 817029a9
CDI 134-7029-3 (GOOD Aftermarket stuff)
 

My_Jet90

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Re: Sportjet 90 - lost spark

That is what I almost ordered last Saturday.
I'll have to dig in the harness to find the other rev limiter connection.

Will let you know how it goes when I get that replaced.
 

kend301

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Re: Sportjet 90 - lost spark

keep posting up , the trigger is out of spec and hopefully it is the only thing bad .
 

My_Jet90

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Re: Sportjet 90 - lost spark

Still no spark with a new trigger installed. The flywheel looks like new magnets all firmly in place. I tested each cylinder for spark now. The RPMs are super fast now that I have all three plugs removed.

I attached a picture of the back of the wiring chasis.

I am wondering if I have the 2 blue wires connected correctly. I looked at my Clymer wiring diagram for the late 90 hp model billet connector style, but it looks like I have a different switchbox because instead of red and blue wires going to the stator I have white/green and green/white. The 2 blue wires that are suspiciously connected to each other. Should one go to the brown rev limiter?

The picture shows one blue wire coming out the end of the switchbox by itself. The other blue wire comes out the side of the switchbox. Maybe the bottom one is unused?
 

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kend301

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Re: Sportjet 90 - lost spark

I'm going to dig out my old switchbox in a bit and look at the wires , Your red stator has green/white , white/green wires that replace the red and blue wires from the black stator . the green/white , white/green should run to an adapter that has a ground wire , and a blue wire coming out of it . the blue wire coming from the adapter should be hooked up to the switchbox blue wire used for the black stator and the red wire for the old stator should just be taped up so it can't ground out . I am thinking someone just used some blue wire for harness repair and that is why you have an extra one. if this is the case you need to trace the other blue wire and see where it goes to
 

My_Jet90

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Re: Sportjet 90 - lost spark

It seems like I have an odd switchbox. Both blue wires come out of the same switchbox. On on the side and one from the end of the same box by itself no other wires nearby.

No atapter before the switchbox. It has the correct colored wires to go directly to the stator and trigger (brown, purple, white and white/black stripe). I am wondering if the sole blue wire from the end of my switchbox should go to the brown rev limiter. That blue wire is extra long and has an extra schielding jacket on it like it was meant to run to the starter side of the motor.

That would leave me with an extra blue wire to tape up running out of the switchbox. How much do new switchboxes run. I can't find any branding or numbers on mine, maybe on the backside.
 

kend301

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Re: Sportjet 90 - lost spark

I think you may have an old ring connector type switchbox , or perhaps an aftermarket box , pull the switch box off and see if there is a cover that removes to expose the wire terminal hookups if so post a pic of the terminals (with wires hooked up ) and I can figure out what is what

Also Is the brown wire from the rev limiter disconnected ??
 

My_Jet90

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Re: Sportjet 90 - lost spark

I am learning in this process.

I removed the switchbox and see that it does have the adapter with the green/white , white/green should run to an adapter that has a ground wire , and a blue wire coming out of it. That adapter box is velcro'd to the switchbox and was so secure that I thought it was a part of that.

So now I do know the 2 blue wires are suppose to connect to each other. I ahve removed all wires from the Rev limiter and still no spark on any plug.

I wonder if I fried my switchbox. I have been using new plugs and can see that plugs #2 and #3 had been firing at some point in my early testing prior to changing out the trigger. Since then I have had all 3 being tested at the same time.

New photo's attached. Do you think it is worth a new switchbox, I could re-sell if that didn't fix me up.


Thanks
 

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kend301

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Re: Sportjet 90 - lost spark

Hook up all the wires to the rev limiter , disconnect only the black / yellow and check spark , if none disconnect the black/yellow at the switchbox and check spark . If none hook all wires up , be sure everything is grounded then run a switchbox bias test as follows

Ohm meter set to 20v DC
Ground red meter lead , Black meter lead to white/black at switchbox
Crank engine and postup voltage reading
 

My_Jet90

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Re: Sportjet 90 - lost spark

2.15 to 2.38 range for the white/black switchbox test. This test reading was taken from the trigger white/black billet connection point to the switchbox.

My new trigger ohms are looking good. All 3 test at 1270 ohms.
 

kend301

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Re: Sportjet 90 - lost spark

Hate to ask you to do this but redo all ohm tests in the Sport Jet Info nad Basics post as a switchbox will be the only option unless you have a DVA adapter to do some more testing , I hate getting to this step !!:(
 

My_Jet90

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Re: Sportjet 90 - lost spark

I ordered and installed a new CDI switchbox and now have tons of spark. Do you suppose the under testing trigger (low ohms on one wire) could have blown out the switchbox?

Thanks for your advice it helped a lot.
My_Jet90
 

kend301

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Re: Sportjet 90 - lost spark

Nothing caused the related failures other than it being a crappy system . One thing takes out the other . New and updated parts prevent lots of these failures from happening but there is no reason or ultimate fix that keeps you from parts failure .... Glad you got her running , I HATE to recommend a switchbox as the only option left as was your case but since it worked .. ENJOY :D
 

My_Jet90

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Re: Sportjet 90 - lost spark

I took another step backwards last night. No spark again after everything was tucked away nice and neat. Got it all ripped apart again and found no reason for it. Did the initial re-tests and no luck.

This motor is giving me a real headache. I'll be retesting everything again tonight. I'm losing the little confidence I had in this boat. It may be time to unload it.

I'll post up what happens next. I have not replaced the stator yet, not much else left to replace.

:confused:

Update:
I have Spark on Cyl #2 and #3 OK. Nothing on Cyl #1. The #1 Coil, wire and plug also test OK when swapping with #2 then Cyl #2 went dead. It followed the green coil wire.
 

kend301

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Re: Sportjet 90 - lost spark

Need to know what you switched out between #1 and #2 , did you move the green wires or did you move the coil ? Proper procedure is to disconnect the wires , move the coil pack , hook the wires up in their original position as follows #1 Green , #2 Green/white #3 Green/red . If the miss then follows the coil it is bad if it stays on number 1 we need to do some tests .
 
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