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Sportjet 120 ignition

Mike Watson

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Hello and thanks in advance for any help you can provide. I bought a 1996 Sea Ray Sea Rayder F-16 with a 120 Sport Jet. I was running the other day and pulled up to the dock and shut it off. It never ran again. I had shut the motor off with the toggle switch but failed to turn off the key for about 20 minutes. It's hard to believe that would cause an issue but hey, what do I know...that's why I'm here! Yesterday I tested for spark on #1 and there is no spark. I'm reading a lot about under the flywheel . I guess my first question is will this motor have spark with a fully charged battery even if the stator is bad? It seems the stator's job is to provide charging to the battery is that correct? I'm wondering if what I have is a bad trigger but I cant seem to find the trouble shooting process for that part. Am I headed down the right path here?

Mike / Daytona beach
 

Ronnie

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I had boats with a a 175 hp and 240 hp 6 cylinder Mercury engines mated to a Mercury jet pumps. Don't know what is causing your problem so suggest you take it to a shop that is familiar with mecury two strokes. They should charge you for about an hour or so of shop time to diagnose your problem. My guess is it will cost $150 at most. When I had I had problems with my 175 hp motor it turned out to be deteriorating needles in the carbs but recall hearing that the staters can be iffy on those motors.

If you still want to trouble shoot it yourself check out this site. You may find what you are looking for.
http://jetboating.net/jetboating/main/main.aspx
 

Cobra Jet Steering LLC

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When I get a few minutes I will fill you in on what went wrong and how to fix it plus how to avoid it happening again, your engine is actually a force outboard power head mounted on a jet pump. Force did that all the time engine runs fine you turn it off and when you go to start it NO SPARK!
 

Cobra Jet Steering LLC

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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 https://www.google.com/?gws_rd=ssl#q=electrolytic+capacitors&*&spf=1534 .
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. upload_2017-3-17_10-30-34.jpeg
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.
 
Last edited:

Mike Watson

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Thanks to all for the input. To date I have disconnected the main wiring harness, no spark. Disconnected the yellow and black wires for the rev limiter, no spark. I have purchased a fly wheel puller and it will be coming off this weekend. My plan is to test the stator and perhaps the trigger before I start buying parts.
 

Cobra Jet Steering LLC

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Suit yourself but I can tell you if it ran fine and you turned off the engine, then when you tried to restart it the engine had no spark , Your brain blew , the cause was what I told you , the stator won't have any issues when you test it but if you just replace the brain it will run ONCE and do it again. GOOD LUCK!
 

Ronnie

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What is the ball park cost of a new brain/ecm? If it cost less than a fly wheel puller I go down that path. The new cost of one for a new Yamaha mr1 is over $1k, used is $300 and up.
 

Mike Watson

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So I went home and tested the stator with an ohm meter. it read zilch. I went ahead and pulled off the flywheel and found that all the magnets were knocked loose and half 0f one of them was gone. There was physical damage to the stator. I went down to my local repair facility / salvage yard and found a red stator that is exactly like the black one that came out of the motor. It has four leads. A green/white, white/green and two yellows. We ohmed out this red unit and it shows 685 ohms. I bought a used flywheel off ebay so I hope to have spark when I'm done.

I do have a question. I've seem postings about a conversion kit for red stators but this one has the exact same wiring as the black one. Am I good to go or will I be needing this conversion before I get this thing running?
 

Mike Watson

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Just to add one more thing. My 120 is actually a 1997 120xr. There is a plate on top of the engine with this info on it.
 

Mike Watson

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So I can close this out I thought I've give an update. I received the flywheel yesterday. I had already installed the red four wire stator, dropped the flywheel on and spun the motor over and just like that I have beautiful spark once again. I sure am looking forward to being on those Florida waterways once again. Thanks to all for the help offered here.
 

Mike Watson

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Ok.. on to my next issue. The boat was starting fine after the flywheel and stator replacement. The shifter was very hard so I took it out and found the shifter to be fine when the cables were removed so I lubed up the cables and it is much better. However I went to start it and it wont turn over with the rocker switch. I was sure to put the neutral switch leads back on but I double checked it. I turned on the key, tried the rocker start switch again and nothing. So I jumped the starter solenoid and she fires right up and shuts off using the lower side of that rocker switch as it is supposed to. Any ideas where to look for this issue? I made sure the safety switch was engaged. But I have no idea how to test it to see if it's actually working.
 

renrab

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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 https://www.google.com/?gws_rd=ssl#q=electrolytic+capacitors&*&spf=1534 .
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. View attachment 52771
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.
LOL do I ever know all about this, ordered a new switchbox from CDI last year thinking it was just my brain, whoops nuked a 250$ part in 10 seconds flat :D
 

Cobra Jet Steering LLC

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been there done that all from a bad rectifier.
 

Caindawg

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Hey guys I know this is an old post however I wanted to share my experiences and how I fixed mine, after a flywheel replacement due to magnets falling off . Motor ran fine then but shut off while operating. I replaced the rectifier and still had no spark however from time to time it would fire. While testing the other components I jumped the solenoid to crank engine withe key OFF, motor fired up and ran great but had no fire with key in ON position. I replaced key switch and it now works great. However I did make the modifications mentioned in the above post about the brain box, just wanted to share
 

TLC86

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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 Google .
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. View attachment 52771
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.
Hello. This post is old but I’m pretty sure this describes the same problem I am having with my sports jet 120. In short, it will not start. New battery won’t hold a charge. The voltage regulator appears to be damaged - small burned out area.

I was so glad to find this post. Since this post was from 3 years ago, would you still recommend substituting the same jet ski rectifier?

Also, could you please give me details on how to install the relay switch? Specifically, where can I find an appropriate switch?

Thank you!
 

Offshore36

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I don't know if you ever solved your problem but the voltage regulator and CDI box for a 120xr Sportjet are on eBay cheap, did you ever fix the problem?
 
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