Sportjet 90 timing issues

[crotonpond]

Hey guys. Hopeing someone can help me out

Im not even coming close to 32 degrees when trying to set the timing at cranking power. Its roughly 20/30 degrees advanced...

Even if the timing linkage is fully adjusted and the Idle and throttle adjustment are set properly..its def. electrical.

 

[jerryjerry05]

Why are you adjusting the timing?
It usually isn't needed unless you change the trigger?

You have the throttle advanced all the way forward?

The static timing procedures are in the first 3 posts.

There is a PWC section in the forums, you can ask there too.

 

[crotonpond]

Well where do I start? lol. I figured i would post here because this boat is essentially a force triple outboard mated to a jet drive.

The boat would not go over idle speeds under load. It would bog and die out. I found unburnt gas in cylinder #2 and #3 and decided to pull the motor for a refresh. New top end, crank seals, gaskets, carb rebuilt etc..

During the rebuild, I found the yellow charging wires from the stator to the cdi burnt. I also found some cobbled up wiring from a previous sloppy mechanic. I went through and cleaned up the wiring and installed a new 16amp stator from CDI as well as a new regulator. I tested the OHMS on the trigger and it was good. I redid all the grounds and removed all accessories from the main motor circuit.

I decided to check the timing at cranking speeds to make sure that the previous mechanic didn't screw that up as well...I'm not even within the degree marks with my timing light. Which is a good unit. I have tried another timing light to verify that out of the equation. Is it possible that my starter is not providing enough rpms at cranking speed?

 

[pnwboat]

What year and what type of ignition system do you have. Might be that the ignition trigger is not wired correctly. That'll throw the timing way off.

Check to see if the flywheel keyway has sheered of and allowed the flywheel to move. Bring number one piston to TDC and look at the timing mark. It should be at 0°.

 

[crotonpond]

The boats a 95. I believe the motor is a 94. Of course the serial number on it was scratched off. Flywheel key is good and I verified 0 at TDC. The trigger was wired properly.

It has the 16amp stator in it with two yellows, green/white and white/green..

 

[crotonpond]

Update...so I have a switchbox and a CDI off a 175XR2 with a wiring harness that appears to have been cut. This boat has def. been hacked together!

 

[Redbarron%%]

Ok check the linkage to the trigger coil lever and compare with the parts drawing.
Also make sure that you do the link and sync as well.
I had similar problems with my 90 sport Jet as well.
On mine the advance would bind because the link was on the wrong side of the tower shaft.
You need to have enough throw to go from 9 degrees and 30.
You need to get the idle timing set correctly and then check the mechanical linkage to get the throw.
I took the throttle cable off the bottom of the tower shaft and tied a cord to the throttle lever so I could go from idle to max (with the kill switch keeping it from firing).
The throttles must be fully closed and the idle stop set.
It took me a while to get everything set so that I could get proper idle and spark timing as well as full throttle opening.

 

[Redbarron%%]

Don't try to use the timing light degree measurement, but find and mark TDC and then count the number of teeth around the flywheel and calculate the proper degrees and see if that works better.
Also check by clamping the timing light on each plug wire to make sure that each is getting a spark. Each firing point would be 120 degrees from the #1.
I am away from the house where I have the boat so I can;t tell you the spacing for 32, 30 or 9 degrees.

 

[Redbarron%%]

When I reworked my 90 I got tired of wondering about the CDI pieces and bought late Mercury CDMs and a wiring harness for a three cylinder Mercury and since they both use the red stator they will work together.
The trigger coil must match the flywheel so if yo have to change that out make sure you get the proper one for your flywheel by model.
The late model trigger uses hall effect sensors and has a different magnetic ring in the inner part of the flywheel and the earlier uses magnetic pickups.
The early system has enough voltage out to fire the CDM modules OK.

 

[pnwboat]

Just for clarification, how far off is the timing?

 

[jerryjerry05]

Static timing:
It's done with the key on, plugs out, throttle full forward and the plug wires grounded.

 

[crotonpond]

Good reading everyone! Thank you.

I have a blown Merc 210 Sportjet here and borrowed the Switchbox from it. After installing it, the timing at cranking is now dead on at 32 like the book says. It appears the switchbox was the problem...

 

[pnwboat]

Those pesky Switchboxes...seem to be a pretty common failure item but I haven't seen one with that symptom before. Usually no spark is the most common symptom.

 

[crotonpond]

So here is my next question....

I have a new 16 amp stator with two yellows and two greens (green/white, white/green)
I have a bad switchbox from a 175xr2
I have a new CDI from a 175xr2

Will any mid to late 90's three cylinder switchbox work? The switchbox from my 210 works at idle but I have not water tested it yet. They all look to be the same, minus different wire coloring.