1993 Sportjet 90hp- No Spark

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
I have a 90 Sportjet that I originally purchased with low #1 cylinder compression. The engine would crank when i bought it but ive never heard it running.

After rebuilding and installing the engine, I can't get it to fire. I have 12+ Volts throughout the starter system as tested by my multi meter. Engine turns over fine but I show no spark from any plug using an inline spark tester. Started looking over the ignition system testing in the Mercury manual but felt a little intimidated.

Wish this site was still up that "kenimPzoom" created, it must have helped a lot of people:
http://www.geocities.com/kenimpzoom/SportJetIgntests.htm

The stator on it is maroon colored but I can't remember the wire colors. I can look tomorrow. Haven't tested the cranking rpm's either to judge that.

Anyone have any other advice?
 

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
Re: 1993 Sportjet 90hp- No Spark

Ok here's some results
3. Disconnect the Black/Yellow wire from the switchbox and check for spark.

(none)

5. Ohm the stator . Green/white to White/green , Post results.

On the k-ohms setting these wires measured .705k

6. Ohm the trigger , check each wire individually using White/black as your ground . First to brown (Measured 1.30k), then to purple (Measured 1.309k) and finally white (Measured 1.291)
 

emoney

Commander
Joined
Jul 19, 2010
Messages
2,551
Re: 1993 Sportjet 90hp- No Spark

I'm by far no "electric man", but figured I'd respond so it stays near the top until someone sees it that can help. If you don't get an answer before long, post a thread in the Chrysler/Force forum as there's a lot more guys active over there, and since this is a Force head (at least my 120 was). But, since I'm here, I will remind you to confirm that the neutral safety switch is good as is the kill switch. Both areas that would cause it to have no fire if they were "activated".

Also, there's a sticky at the top of this forum that talks about all things "stator related". Might want to browse that to see if your answer is there. There have been a couple guys that pulled their flywheels and found that some of the magnets came loose and needed epoxied back into place. Just a couple of ideas I figured I'd throw out. Good luck!
 

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
Re: 1993 Sportjet 90hp- No Spark

But, since I'm here, I will remind you to confirm that the neutral safety switch is good as is the kill switch. Both areas that would cause it to have no fire if they we're activated. Good luck!

I think I did the test for the kill switch at the switchbox. If it involves disconnecting the black/yellow wire from the switchbox then I still did not get any fire to the plugs.

So far I'm thinking it's the stator. I have a black one that seems to be good but it has different wiring schematics than what I have.
 

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
Re: 1993 Sportjet 90hp- No Spark


Thanks for the links. I have an older sport jet manual but the newer revised section you posted above is more helpful. Tomorrow I am going to use these links to test the stator again. I may even try to install the black stator that I have that has the extra two red-white & blue-white wires using the cdi installation instructions posted above. The extra stator that I have has part #398-8778A24 printed on the top of it.

I also ordered a dva tester off of amazon to test the dva outputs but it won't be in till the end of the week.
 

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
Re: 1993 Sportjet 90hp- No Spark

I'm not having much luck with further testing.
 

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
Re: 1993 Sportjet 90hp- No Spark

I'm by far no "electric man", but figured I'd respond so it stays near the top until someone sees it that can help. If you don't get an answer before long, post a thread in the Chrysler/Force forum as there's a lot more guys active over there, and since this is a Force head (at least my 120 was). But, since I'm here, I will remind you to confirm that the neutral safety switch is good as is the kill switch. Both areas that would cause it to have no fire if they were "activated".

Also, there's a sticky at the top of this forum that talks about all things "stator related". Might want to browse that to see if your answer is there. There have been a couple guys that pulled their flywheels and found that some of the magnets came loose and needed epoxied back into place. Just a couple of ideas I figured I'd throw out. Good luck!

I went ahead and posted to that section as well too. No hard feelings to this section but I really want to get to ride this thing before it get cold!
 

Anders67

Petty Officer 2nd Class
Joined
May 23, 2012
Messages
117
Re: 1993 Sportjet 90hp- No Spark

Hi.

You have put all electric wireing right after restoration and connect up the engine again?.

What do you get when you ohm stator as the says in manual ?. Volt and ohm rec.. I suposed you had the old ing. system on you engine.

What color do you have on the wiering from stator ?. Black , blue , red and two yellow?. See you wright green/white , white/green before in the thread.

Do you have the old type of Coils?.
 

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
Re: 1993 Sportjet 90hp- No Spark

Hi.


What do you get when you ohm stator as the says in manual ?. Volt and ohm rec.. I suposed you had the old ing. system on you engine.

What color do you have on the wiering from stator ?. Black , blue , red and two yellow?. See you wright green/white , white/green before in the thread.

Do you have the old type of Coils?.

I have the red stator with the Green/White & White/Green wiring plus the two yellow wires. When I tested the Green/White & White/Green wires, they measured 705 or 680 ohms. On one of the CDI Troubleshooting Guides, it says that the reading should be around 500-700 for OEM Resistance on the RED STATOR.

This is a photo of the side of my engine.
image.jpg
 

Anders67

Petty Officer 2nd Class
Joined
May 23, 2012
Messages
117
Re: 1993 Sportjet 90hp- No Spark

Hi.

Ok then they have switched the stator sometime. You shall have a module/adaptor kit between stator and switchbox. Becaurse the newer one gives more power. Seems that you have it in the bottom of the picture.

http://www.crowleymarine.com/mercury-outboard/parts/1546_70.cfm

Number 37, 38, 39 in picture.

If you have that ok. Start looking on switchbox. And rest as manual says, and test it as the manual pdf says that i linked. The manual seems a little messy in the beginning, but it cleares out if you read it over some times. It is that way to test out the components in order. You can also diskonnect the rectifier and se if spark back. If it is. The recti. is shot.


Seems like your trigger ok. on the readings.

Ohm green/white White/Green between each other and result shall be as ok. 500-700 it seems, but it can wary some of temperature difference. Ohm eatch of the two to ground and there you shall not have any reading (open).

Check again so grounding is good for everything, and so all wires is in right places.
 

hypersniper

Banned
Joined
Jun 18, 2011
Messages
104
Re: 1993 Sportjet 90hp- No Spark

Anders67... looking at his picture did you notice he does not have the candy bar size adaptor that is needed for the red stator upgrade ? he may have fried the switchbox without it. and without sounding like a bottom feeder i do in fact have a good updated switchbox and if you do stay with the same switchbox style i do also have an adaptor. i no longer have my jet boats but do have alot of good extra parts. and i have also learned alot about jet boats on here from these guys.
 

Anders67

Petty Officer 2nd Class
Joined
May 23, 2012
Messages
117
Re: 1993 Sportjet 90hp- No Spark

Hi. Isn?t it the adaptor sitting leveled in front of fuelpump?.


Regards
 

hypersniper

Banned
Joined
Jun 18, 2011
Messages
104
Re: 1993 Sportjet 90hp- No Spark

woops , my bad i didnt see it sitting there. kinda blended in and its a small picture but yes your right. sorry.
 

cowansauto

Seaman Apprentice
Joined
Jul 11, 2012
Messages
38
Re: 1993 Sportjet 90hp- No Spark

I figured out what was wrong with the no fire situation....the switchbox was bad. I recieved the dial type meter that is uesd in the Mercury service manual and went thriugh the steps and found 0 volts on one of the test steps were there should have been alot more than 0. I bought a used CDI unit off of eBay, got it installed and now there's spark on all three but the engine would not go ahead and run. I'm going to make another post just on this new issue I believe.
 

Anders67

Petty Officer 2nd Class
Joined
May 23, 2012
Messages
117
Re: 1993 Sportjet 90hp- No Spark

Hi. Check so you have right timing. When that?s okay and spark plugs okay.

Spray a little fuel ore start gas in the carbs and se if will fire up.

If it does. Over to fuel.

Disconnect fuelline from pump to carb and put hose in a bottle. Turn over and se so fuel is comming.

If. Check choke, reeds and Carbs.
 
Top