Mercury Sport Jet 90 - Rev Limiter and Switch Box Tests?

Ronski

Cadet
Joined
Sep 19, 2012
Messages
9
This is my first post and I am new to this forum, but not new to boats and engines. I recently bought a 93 Sea Rayder with a Sport Jet 90. I purchased it ?as is? with known electrical issues (no spark). I have since removed all the electrical components and wire hardness. It was in poor shape with many splices, bad terminals and grounds. The ignition plate also has a fair amount of rust on it. At some point in the motors life, the stator and regulator were replaced with the ?red stator? and ?design 2? regulator. But who ever did the work back then did not do a good job wiring in the new parts.

I have started to test the existing components. The stator resistance test shows low resistance across the yellow leads (0.2 to 0.3 ohms below spec). The regulator tests open circuit. I have not tested the switch box or rev limiter. Two of the three coils test very high resistance and the third slightly above spec.

I have heard that a bad rev limiter can kill other electrical components in the system. Is this true? Is there a standalone test I can do on the rev limiter to make sure it is good? I would hate to install a new stator, regulator (and maybe switch box) only to find that my existing rev limiter killed the new components.

Also, is there a standalone test that I can do on the switch box? From what I have read, it needs to be connected to other components for testing (from Sport Jet service manual).

One other question. What is in the candy bar shaped component that is used with the red stator? Is there any way to test it? I was not planning to buy this with a new red stator (person selling stator does not have this part).

Sorry for all the questions, but I figured there had to be someone else who went down this same path and has some useful information.

Thanks very much for the help.

Ron
92 Sea Ray Sundancer 230
93 Sea Rayder F14
(and to many cars)
 

Ronski

Cadet
Joined
Sep 19, 2012
Messages
9
Re: Mercury Sport Jet 90 - Rev Limiter and Switch Box Tests?

No suggestions?? I am sure there have been others who have tested these parts. Thanks.

Bump
 

Craighimself

Cadet
Joined
Mar 27, 2012
Messages
14
Re: Mercury Sport Jet 90 - Rev Limiter and Switch Box Tests?

Check you kill circuit... the black with yellow wires.

one to rev limiter, one to switch box, one up harness to keyswitch and kill switch and one to each coil.

unplug all black/ylws and check for spark
then plug eack component in to eliminate problem


then check each coil. its easier to check resistance on stator and plug each coil in one by one and watch for ohm drop.

1 coil can send all stator voltage to groud and leave the spark circuit dead.
 
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