Sport Jet 90 maybe needs Switch Box

bclery

Recruit
Joined
Jul 27, 2009
Messages
2
I just purchased a 1994 Jazz with the Sport Jet 90. Yes, I read all the warnings but bought it anyway, pretty cheap from a guy that had not used it in a few years. It is very very clean and everything mechanical seems to have been maintained well. but of course it doesn't run :)

Thank you very much for any feedback on my testing and conclusions.

I am not getting a spark and I am pretty sure I need a switch box, but need a sanity check before I drop $200.

I disconnected the rev limiter

I disconnected the black/yellow kill line.

The engine had a black stator and the switch box with wires & plugs (not the switch box with terminal bolts). I have a receipt showing that the stator had been replaced back in late 1994, but apparently it was replaced with another black stator.

The stator ohmed out way low (1400, should be 4000) so we replaced that. The new stator we got is the red one with the adaptor. New stator is ohming out properly and puts out good AC voltage (green-to-white). On the other side of the "red stator adaptor" at the blue wire we seem to be getting 120 DC volts rather than AC. Is this normal? What is the expected output from the blue line on the red stator adaptor.

What is in that adaptor ? If the red stator feeds a different voltage to the old switch box then how can the old switch box take that ?

The spark plugs are funky with no electrode. Should I be able to see a spark like I would on a normal spark plug?

The black/white bias line from the switch box looks reasonable. I get a pinch less than 2 volts while cranking.

The black/yellow line from the switch box is giving the same 120 volts DC that I get from the stator adaptor blue line. I do not know if that is good or bad.

The trigger looks good. Good ohmage and a small AC output voltage when turning on all 3 lines. (I do not have a DVA and the trigger output is tricky to convert from an AC measurement)

I get no spark on ANY of the 3 coils. Is that a normal failure mode for the switch box? All 3 die at once ?

All the coils ohm good from negative to plug wire. The ohmage on the coil neg to pos is too low to measure (less than 1 ohm).

I see NO voltage from the switch box to ANY of the coils. Even with the wires disconnected from the coil.

So, is the switch box bad? Or am I missing something about how this new red stator works? It just seems against the odds that both the stator and the switch box went bad at the same exact time.

Side notes about the regulator:

I know that the old 9 Amp regulator can't really handle the new 16 Amp red stator. But, can I just run it till the regulator gives out ? what harm ?

If I run the engine with the two yellow wires disconnected (stator to regulator) will that hurt anything? I believe it will simply not charge the battery.
 

redroell

Recruit
Joined
Jun 25, 2011
Messages
1
Re: Sport Jet 90 maybe needs Switch Box

wondering did you find the fix for yours? i have a donzi with a 90 sport jet and have almost the identical problem.
 

jet90

Recruit
Joined
Jun 28, 2011
Messages
2
Re: Sport Jet 90 maybe needs Switch Box

Hi,

Just picked up a 1995 bayliner sport jet 90 with no spark, noticed it also has the black stator and i have no spark. any advice?

thanks.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Sport Jet 90 maybe needs Switch Box

Ohm readings are NOT necessarily a determining factor as often a stator will Ohm out of range yet generate voltage just fine.

Direct Volt Amp (DVA) measurement is THE most reliable method of testing generator coils such as found in stators and triggers.

DVA adaptors are available for reasonable price or you may buy the parts and assemble one quite cheaply to use with your volt/ohm meter.

Testing is clearly spelled out in the Ignition Troubleshooting Guide found on the CDIElectronics website.

Your old stator MAY have been bad. Prove your new stator good, then order a switchbox.
 
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