90HP Mercury SportJet Timing problems

[john_pike@hotmail.com]

This is a SugarSand, Mirage, 1993, sn 0E071723. I have owned the boat for two years. Had problems starting when hot. Replaced Battery, solinode, batterycables. Then replaced stator (black) with CDI #174-8778K1. Now, it starts great but will not run past idle speed. Any accelleration and the timing advances way to much. <br />Replaced Trigger after finding one lead had low resistence with merc. part and replaced all three coils. Replaced rev limiter as well. The closest I can get starting timing is about 28degrees. Idle timing is about 30degrees. <br />Do you think there is a problem with the switch box? Do I have something wired up wrong?<br />Thought maybe the stator was in wrong but CDI told me it does not affect timing. <br />Please help, tired of paddling.

 

[rodbolt]

Re: 90HP Mercury SportJet Timing problems

Hello<br /> did yor trigger coil get moved when you replaced the stator? did the flywheel key get sheared or dropped? if you dont belive that the stator will have any affect then why does the red stator kit have 3 sets of arrows that must face aft depending on what engine it is going on. a good reason why I stick to factory parts only. they work and work well( most the time)index the flywheel by rotating the flywheel with the #1 plug out and use a straw to feel the piston coming up. you can get it very close by rocking back and forth. when the piston is at TDC then look at where the flywheel marks are. if it is correct I think you may have something miswired<br /> good luck and keep posting

 

[john_pike@hotmail.com]

Re: 90HP Mercury SportJet Timing problems

The flywheel key is fine. I have pulled it twice to verify. I replaced the trigger coil and have not been able to adjust it enough to make a difference. I have gone from one end to the other with the adjustment screw. I'm hopeing someone out there can tell me what's wrong with my wiring or if my switch box is bad.

 

[kenimpzoom]

Re: 90HP Mercury SportJet Timing problems

Check out my homepage (link in my signature). It has wiring info and diagnostic info. Wiring is fairly basic on this engine. I dont THINK the stator position should effect the timing, but not positive.<br /><br />Are you sure all the throttle / timing linkages are set up properly?<br /><br />Are you using a standard plain jane timing light, or one with that is adjustable. I have heard that those adjustable models can make the timing way off.

 

[john_pike@hotmail.com]

Re: 90HP Mercury SportJet Timing problems

Throttle linkage has not been adjusted since it worked. Using standard non-adjustable timing light.

 

[kenimpzoom]

Re: 90HP Mercury SportJet Timing problems

Are you saying that you can move the adjustment screw on the timing trigger and it has no effect on the advance, or moves it in the wrong direction?<br /><br />Check to see that the wires from the switchbox are hooked up to the correct coil.<br /><br />I think (from my memeory so I could be mistaken) that the top coild should have the solid green, the middle coil has the green/white stripe, and the bottom coil has the green/red stripe.<br /><br />Which type of swithcbox do you have, bullet connectors, or ring terminals?<br /><br />Ken

 

[rodbolt]

Re: 90HP Mercury SportJet Timing problems

Hello. did you index the fly whell to rule out a misplaced timing pointer? it sounds like the charge coils are in the wrong place.<br /> the wiring on that motor is straight forward. make sure the correct trigger wires are attached to the proper pack terminals. if the timing issues started with a stator change I would look at that very close, also mark the flywheel at TDC for the #2 and #3 cylinders and check for a cross firing condition.I still think the stator is in the wrong position.<br /><br />good luck and keep posting

 

[john_pike@hotmail.com]

Re: 90HP Mercury SportJet Timing problems

I tried moving the stator to several different positions. This has no effect on the timing. <br />I can adjust the timing on the trigger but with it turned all the way, I am still advanced too much. Is it possible the inner magnet assembly has somehow shifted? Could the controll arm for the trigger be bent? Or does it sound like my switch box is bad? I have triple checked the wiring, (bullet connections) and they all seem to be correct. When I move the throttle forward, the timing advances way past 32BTDC and the engin starts missing. At idle, it is running at 32BTDC. Cranking it is about 10BTDC, book says it should be 0degrees.

 

[kenimpzoom]

Re: 90HP Mercury SportJet Timing problems

John Pike you have me stumped. I am grasping at straws with the questions below.<br /><br />You say you replaced the trigger coil, did it have the "advancing problem" before you replaced the trigger coil? Perhaps you got a badly made new trigger coil?<br /><br />Just to make sure, you are setting the cranking timing at 30 degrees with the throttle wide open, correct? On the #1 clinder (top cylinder)<br /><br />I dont see how the inner magnet could move, but stranger things have happened.<br /><br />I also dont think your switchbox could do this. All it does is take the energy from the stator and fire it to the coils when the trigger tells it to. Its only components are switches, capacitors, and resistors.<br /><br />Are you certain you have the linkages exactly as they should be?<br /><br />Ken

 

[john_pike@hotmail.com]

Re: 90HP Mercury SportJet Timing problems

The timing was off before I replaced the trigger. It has been off since I replaced the stator with a CDI p/n 174-8778k1. I replaced the trigger in hopes that the timing would work. The new trigger is p/n 817029a9. Unplugging the black/yellow wire on the limiter makes no difference. All the magnets, both outer magnets and the inner magnet assembly in the flywheel look and feel solidly mounted. The orginal problem was it would not start after it had been running for a while. It ran strong before, full throttle would get me to 37-39mph. Now, as soon as I advance the throttle past idle to the point the trigger starts to advance, the timing advances past 32degrees BTDC and the engine starts missing and will die. The timing stays the same, regardless of what position I mount the stator. At idle the engine is strong. The flywheel key is in place when I mount the flywheel, I marked it with nailpolish and I can see it with flashlight, when I put the flywheel on the spindle. I have replaced all three coils and they appear to be working properly. I have tried the recommended surface gap spark plugs and tried old style plugs with .30 gap. Neither of these make a difference. I have replaced the sparkplug wires. I have checked all the grounds. I replaced the starter solenoid and put 4 gauge wires to and from the battery. The only parts not replaced are the ignition switch, the voltage regulator, the switch box and the wiring harness. The boat ran great before, it just would not start after I took it out which is why we replaced the stator.

 

[kenimpzoom]

Re: 90HP Mercury SportJet Timing problems

More straw grasping.<br /><br />Did your new stator come with the "red stator adapter"? Does it require one? I have heard that CDI stators do not need the red stator adaptor.<br /><br />What color are the wires from your new stator?<br /><br />Have you tried to go back to your original black stator, or is it dead?<br /><br />I am asking about the stator because that seems to be the point that your problem started. I dont see how that could cause it, but who knows.<br /><br />Can you post a pic of your linkages?<br /><br />Ken

 

[SB]

Re: 90HP Mercury SportJet Timing problems

The CDI stators do not need the red stator adaptor. They should be a direct replacement for the black stator. The CDI does have a few extra wires and these need to be grounded for a 3 cylinder. These are the Red/White and the Blue/White wires. The instructions are in the box.

 

[john_pike@hotmail.com]

Re: 90HP Mercury SportJet Timing problems

Got back into it this weekend. I noticed an oily deposit on the bracket that holds the coils in place. It appears to be coming from the voltage regulator. I took the regulator off and tested it. It does not give any off the manual values. It shows 1.6Mohm between one yellow and red both directions and 56kohms between the other yellow and red in both directions. Book says continuity in one direction and open in the other for each wire. Looks like the regulator is bad. <br />Does anyone know if the CDI stator requires a special regulator? I got p/n 174-8778K1 to replace a mercury black stator.<br />I am planning on getting a DVA for my Fluke multi-meter to check the switch box. Hope to get running this weekend.