Re: emptied fuel tank (results)
 

further apart.....but still intermittant seems i get a little more time if good running with cover off byt still bogs out

Re: emptied fuel tank (results)
 

engine is missing , all three left bank cylinders , pulled the plugs one at a time with engine running, no difference on any cylinder left port bank ....all are sparking but the sparks are shooting everywhere !! what can it be , a bad ground ? short? cdm ? im puzzled ! right starboard bank all made a change when pulling those wires one at a time !

Re: emptied fuel tank (results)
 

Coil base timer under the flywheel, or power pack possibly...?

Feeling a bit more close now- I wound up having to throw both in and viola...!

Re: emptied fuel tank (results)
 

im leaning towards this (shift interrupt switch )


TROUBLESHOOTING IDLE STABILIZER SHIFT SYSTEM
When outboard is idling IN NEUTRAL, shift switch circuit is in the OPEN position and system is INACTIVE.
When outboard is shifted INTO GEAR, shift switch circuit CLOSES. BIAS VOLTAGE from each switch box is changed by a 6.8K (±.34K) resistor located in the WHITE/BLACK lead between the switch boxes and the shift switch. The shift switch is now CLOSED and completes the circuit to ground. THREE DEGREES of timing advance occurs when the shift system works properly.
If the resistor is OPEN or the shift switch circuit stays OPEN, the THREE DEGREES of advance will not occur when the outboard is shifted into gear AND maximum timing at W.O.T. will be RETARDED THREE DEGREES.
If the resistor should SHORT TO GROUND, engine timing will be overly advanced and damaging powerhead detonation will occur.
Connect a timing light to No. 1 spark plug lead (top, starboard bank). Start the engine, and allow it to idle above 600 RPM, then retard the ignition timing by slowly pulling forward on the spark advance lever. Observe that the system is functioning by noting a rapid spark advance (as much as 9° from the idle setting) as the engine slows down to below approximately 550 RPM.
The idle stabilizer is not repairable. Should the idle stabilizer fail to function as described, it will require replacement.
90-898303 2-27

Notes

Re: emptied fuel tank (results)
 

replaced the shift interrupt switch and no help !! took the wire off the center #4 cylinder and rescrewed back on to coil and the sparks stopped flying all over the place ! but the plugs are still fouling which to me are still not firing correctly

Re: emptied fuel tank (results)
 

Trying to understand what you mean by "sparks flying all over the place "

Re: emptied fuel tank (results)
 

when pulling the wires off the plugs while running ,(seeing if the cylinders made any change ) I was getting shocked , and when I grabbed a rubber gripped pliers instead of fingers the spark was not only going through the rubber handle but you can see the sparks flying trying to hit anything it could. at least its sparking !!! lol ...but I cant figure out why its not firing properly , im gonna do one more thing, adjust the sensor on the fly wheel for timing.....

Re: emptied fuel tank (results)
 

A friend of mine has the exact same issue with his Mercury 2 stoke carbureted engine. You pull the plug wires off one side of the engine at idle, you'd think it would make the engine run rough or stall and it makes no difference what so ever... Put the plugs wires back on that side and take them off the other And the engine stalls. He's had it to a few Merc mechanics and they can't figure it out. Engine runs a little rough at idle and seems to run fine up to 4000 rpms and after 4000 it starts to surge.

Damdest thing and will be watching this post to see what you find.

Re: emptied fuel tank (results)
 

today , i took off the throttle body again , then the reed block , the reed block seems to be in great condition ....the reeds are tight , i decided to put the body on with out the cover to see how the injectors where firing , they seems to be firing just fine . sprays even in all 6 injectors the reeds open and close fine , its getting fuel .....now im leaning to the coils or the computer ..bringin to the dealer with a list of everything ive replaced and tried .....see what they come up with ...im going through (captain of my own boat withdrawls ) and very very aggrevated ( upon pulling the reed block it opened the crank case and let me tell u its is clean as a whistle inside the case pistons are immaculate , the cylinders look great ,and u would think it was a rebuilt engine ! )