Sportjet90 electrical issue

[Steve1986]

Im in some serious need of help and suggestions. I have a 1993 searayder with sport jet 90 in it. Long story short the rectifier melted on me so i went and replaced it. Cleaned of all grounds while waiting for the new one to come in. All cleaned up ready to go i go to turn the ignition switch and nothing. Then i went to jump it from the starter solenoid it turns over but still no start i have good spark. Verified that. Baterry is full charge as well. No idea of what i could of messed up. Any suggestions very much appreciated.

 

[alldodge]

The guy that is good with these no longer comes to iboats, you can find him on jetboaters. Name is Mark and is under cobra jet steering. In any case, he says these are Force outboards, and when the rectifier burns out it also burns out the brain. Only way to get them up and going is to replace the rectifier and brain at the same time.

Mark says its best to get rid of the sport jet, there just not worth the trouble.

Have a read on this thread

https://jetboaters.net/threads/sportjet-120-ignition.12682/

 

[roscoe]

There is no brain or cpu.

If if you have spark, the stator, trigger, and switch box are working.

Check timing, then move on and check fuel delivery and compression.

 

[Redbarron%%]

First check the timing at TDC to make sure that the flywheel key is not sheared, throwing the timing off.
If the TDC is correct then if you have the ignition on so that the kill black with yellow is not grounded you should have spark.
View attachment 1993 90 hp electrical dwg..pdf
Do you have the black or the red stator (look under the flywheel from the left side)?
If you have the red stator and the small Hershey bar adapter they you could upgrade to the Mercury CDM ignition fairly easily and cheaply (Less than a new switch box)
If the rectifier fails then it will often kill the switchbox.
If you get the engine to turn over from the ignition switch (see electrical drawing) then check the timing turning over the engine with the starter. If you have the trigger coils going to the wrong terminal then it will fire but the timing will be at least 120* off and it certainly will not start.
I have a 1995 Hobie Jet Skiff Fisherman with the 90 hp sport jet and my opinion is that the bad reputation is mostly from the older Force ignition and electrical system.
I upgraded my system to the late Mercury CDM modules using the 200 hp CDMs and a three cylinder harness from a Mercury.
As far as the two stroke engine itself is is no better or worse than any of the same period.(old technology 2 smoke).
I bought a cast off 1994 Regal Rush for the motor to rebuild or freshen up for a spare including the Mercury CDM system.
I also replaced the rectifier / regulator with a Motorcycle MOSFET unit to eliminate that old technology as well.
So.
See electrical drawings to track down the starter problem.
Check the TDC for 0 and the flywheel.
Check timing with a timing light to make sure that #1 fires at 9 * at idle and 32* at WOT (cranking speed).
Check that #2 fires at 129* etc...
Also the NEUTRAL switch on the throttle must be made.
The starter will not work if not in neutral! (assuming that it has not been jumpered).

 

[jerryjerry05]

If there is spark? then the neutral safety switch works.
Like the others suggested, check the flywheel key.
Water in the fuel?

There is a PWC sportjet forum here at iBOATS

 

[Redbarron%%]

The Neutral safety switch is in the Yellow/Red wire from the starter switch (start contacts) to the solenoid. It has nothing to do with the ignition on the Sport Jet, just will not spin the starter if not in neutral (again assuming that it has not been jumpered out over the last 25 years).
You have a silver button on the throttle/shift that if pulled out in neutral will let you move the throttle wit the gate still in neutral position and will let the neutral safety switch stay on since it works off of a cam on the shift part of the throttle.


From Jeff at CobraJet steering posted above:

Force had a lot of issues with the field windings under the flywheel so they built a new style stator that was supposed to resolve those issues, but honestly it DID NOT fix the problem. Your problem is due to a bad rectifier, the older 2 stroke outboard engines used a rectifier that changed alternating current from the stator into pulsating D C current by utilizing electrolytic capacitors , these create a ONE WAY door for the electricity.
The field windings for the charging system are very close to the windings for the ignition up under the flywheel. When you turn off your engine it continues to spin for a few seconds, If your rectifier goes bad it allows 12 volts from the battery to travel up to the field windings and that creates a bastard field, this overwhelms the ignition windings and in a flash it burns out your brain for your ignition. So what happened was your rectifier went bad and burned out your ignition brain. What I did in the past was to install a new rectifier and brain plus wire in a relay switch in the red positive wire of the rectifier to the battery that opened when the ignition was turned off and closed when the engine was running so the path to the positive side of the battery between the stator and the battery was eliminated when the engine was turned off. It worked great. However I later tried removing the old style rectifier and replaced it with a jet ski voltage regulator that not only changed the current to dc but regulated it to keep it from surpassing 14 volts and it discharges any excess current to prolong the life of your battery and prevent overcharging, A stator will put out 17 volts depending on the R P M. a regular rectifier will send all the current directly to your battery.
On a voltage regulator you will see the same wiring as your rectifier 3 field windings usually yellow wires a ground usually black or just the housing of the rectifier is ground and a red positive wire that goes directly to your battery, so doing a changeover is fairly simple I later did this to all my older outboard engines as well.
In any event you will need to deal with the problem of a bad rectifier and replace the brain, check with NAPA auto parts have them look in the SMALL engine parts catalog because those people were selling all the electrical components for the old force engines back when I worked on them, perhaps they have some leftover. You will also need to replace your makeshift wiring and install a proper marine ignition switch for safety.
If you just replace the brain it will run once and then die as soon as you turn off the engine so don't do it. By the way a voltage regulator like the one in my picture can be purchased for about 20 dollars on line NEW. This info applies to the 90 hp also.​

 

[Steve1986]

Thank you guys for all the input i got in touch with Mark( cobra jet steering llc) he gave me links to a couple of threads that make me believe the switchbox and stator is fried. My question would be is it possible that a fried stator ignition windings and a switchbox prevent it from turning over at all. I have 0 response from the ignition key. No click no noise nothing like the is absolutly 0 power. When jumped the starter solenoid the engine turned fine no start but i had a spark in #1 cylinder did not check #2 and #3. Thank you for your time.

 

[Steve1986]

I did a little troubleshooting this morning to see some resistance values on the component i used a resistance chart from CDI electronics website for my MY engine and the red stator kit only value i found out of spec was the blue wire on the ignition adaptor it reads value to engine ground. Please see attached pictures. Problem is still present the boat would not turn over at all.

 

[alldodge]

would not turn over at all

Measure voltage on the Red wire on the start relay (12V)
Measure voltage on both sides of the 20amp fuse (12V)
Measure voltage on the key switch Red/Purple wire (12V)
Turn key to start, measure voltage on Yellow/Red wire on key switch (12V while holding key to start)
Turn key to start, measure voltage on Yellow/Red wire on start relay (12V while holding key to start)

If you do not get 12V on Yellow/Red wire on start relay, check neutral safety switch

 

[roscoe]

Funny how the info keeps changing. Spark no spark etc. no there is no way a bad stator trigger or switch box will prevent the starter from engaging.

Sounds like blown main main fuse or solenoid but really no way to tell without starting over and doing proper diagnostics. Fuel spark compression. Then narrow it down from there

 

[Redbarron%%]

MOD EDIT I would not replace it or the switchbox as I would spend the money on a three cylinder Mercury harness and CDMs on ebay.
The red wire from the adapter replaces the high speed coil from the old black stator. The blue wire is the low speed power from the old black stator. The adapter simulates the output from the old black stator.
If I am correct the engine would run on at low speed and not high speed.
The Red Stator has only the single green and white and white and green that is compatible with the CDMs and the existing trigger coil will work also as long as the original flywheel is used. The output from the trigger is higher at 4 volts than the new one at 2 volts since the new one has a single coil and the old has two coils in push-pull to give the higher voltage.
At any rate if you get a spark at cranking speed I would concentrate on the starter for the convenience of testing.
The troubleshooting above should help isolate the problem. A bad stator will not keep the engine from turning over as the ignition system is isolated, even though the feedback from a rectifier short could damage the old switchbox.
If the fuse is bad then you will not get power to the key switch on the purple wire and that is a good possibility for your starter problem.
The battery 12 volts goes through that fuse to the key switch and all of the accessories. Someone may have jumpered the fuse or put in a larger amp fuse and a short in the accessory power could have helped burn out the rectifier/regulator.
Not only that the rectifier / regulator might be the one for the old black stator that would only put out 9 amps where the red stator would need to have the proper unit for the the 16 amp red.

 

[Redbarron%%]

Also Roscoe is correct. Start at the start and work logically.
Do not jump around, but rather concentrate on one thing at a time.
No one can fix a dozen things at the same time.
Step by step.
Fix the starter
Disconnect the rectifier and test the spark on each cylinder with an clamp on timing light and check the timing at the same time.

 

[Steve1986]

Ok guys starter problem miraculasley disapeared i went to troubleshoot as per the drawing and i decided to give it a try before i start and it started cranking on to the next step

 

[Steve1986]

Latest update once i got water flowing thru the engine i crancked it it started and idled fine no problem baterry was charging. The only thing was it wouldnt turn off from the key i pulled the black/yellow wire grounded it and it shut off. Then i went to button it up and after that dead again i got 12v to the purple and 12v to yellow/red when i turn the key on but nothing at the starter solenoid so it must be the neutral switch weird afted i bolted the plate with the electrical components the problem returned im also suspectin shortin somewhere there couldnt find anything with the meter.

 

[Redbarron%%]

It may be that the neutral switch is intermittent or the cam that works it is not aligned properly.
If there is a short then the fuse would blow and if it is an open then the current will not flow to the solenoid.
One of the barrel connectors might be intermittent as well or perhaps the big electrical connector might nor be making up.
Many of the neutral switches have been jumpered and for a test this might be worthwhile.
With the grounding not making on the stop black and yellow it might be a engine plug that might be served by unplugging and reconnecting to clean the pins.

 

[jerryjerry05]

Sounds like the Neutral Safety Switch isn't aligned or the key switch is dirty/corroded.
WD-40 or Contact spray in the switch.
Unhook the battery, turn the switch/activate the choke- repeat 15-20 times.
Spray again and then use WD after the last spray.
Blow the switch with air after done.
Check the connections on the back.

Key OFF!! Shift the motor as someone turns the prop.
If the props not moving, you can cause damage.
Shift to N and then check the alignment of the neutral safety switch.

 

[Redbarron%%]

On the Sport Jet the neutral is not actually putting anything in neutral, but rather dropping the reverse bucket 1/2 way down so that the boat doesn't move (much). The impeller in the jet will turn anytime the motor turns.
The neutral safety switch is to make sure that you don't take off if started with the throttle open.
The Sport jet also does not have a separate water cooling pump or impeller as it steals water from the main jet pump.
If you are running in the driveway the flush attachment on the top of the engine head is not for that, but just flushing.
If you are running out of the water then you need the dealer cooling adapter that goes in the water line from the pump on the right rear of the pump a 5/8" flare fitting.
Also if starting without the dealer adapter fuel collected on the ride plate has been known to explode, bending the ride plate making even more problems.
Get some contact cleaner and clean the engine plug and the bullet connectors. The switch could be corroded, but you had power past the switch on the red / yellow wire so either the switch or the plug are suspect.
I am leaning towards the plug since the kill switch did not shut off the engine and this is where both are present and there is no other breaking point for the kill switch.
Logical tracking of the current paths will yield results, keep it up!

 

[Steve1986]

Sounds good guys i will get after that and post an update. And yes for running the engine i went to lowes and got the "dealer" setup for $9 it works great so i can test run the engine in the driveway at idle of course i will not rev it at any point hooked up just to the hose i also know about the water pressure need to be low to a trickle so it wont fill the cylinders. Thanks everybody im going to dig into it

 

[jerryjerry05]

I forget it's a sportjet

 

[Steve1986]

So far so good guys i went into the electrical connections and found that the 20A fuse was intermittent the fuse holder itself cleaned the up also the cannon plug on the main wiring harness got cleaned, verified all grounds, replaced the deadman switch that seemed to fix my problem with starter not turning. I put it on the water ran good. I have a couple of small issues i need to adress 1 when i put throttle in N the engine rpms dont go back all the way to idle but remain a bit over its not the cam follower on the tower shaft since its not touching and im having hard time starting it cold once it starts and it warms up it starts right away no problem but initial i need a short squirt of carb cleaner to get it going. Other that that ran like a champ.