2002 90 hp 2 stroke no spark

had to get towed back to port yesterday from watch hill reef.have 2002 90 hp johnson 2 stroke motor running fine all day til went to make another drift motor started then sputtered and stopped running couldnt get started again...changed spark plugs ....then found had no spark..never had this happen b4 ..any input into were to start looking to correct problem would be great...what color wire from key switch to motor is for power....turns over fine ..no spark

Do not look for or attempt to apply "power/voltage" to that ignition system as it is self contained. The stator under the flywheel delivers approximately 300v AC to the powerpack and there is the beginning of the ignition system.

What to look for is the kill circuit..... the "black/yellow" wire that is attached to (usually) a raised tower like terminal of the ignition switch which is labeled "M".

Remove the spark plugs so that the engine turns at its highest rpm for a spark test. Rig a tester so that you can set a 7/16" gap for the spark to jump (the gap is important). The spark should jump with a strong blue lightning like flame... a real SNAP! Note that testing the spark by using the spark plugs is a waste of time.

Remove the "black/yellow" wire from the ignition switch. Crank the engine and observe the spark. If you have proper spark with that wire disconnected but no spark with it connected, replace the ignition switch.

If still no spark, the problem is usually a failed powerpack... however, closely inspect the stator under the flywheel which is a two fold component as it is the beginning of the ignition system and also the beginning of the battery charging system. If that stator should be dripping a sticky looking substance down upon the powerhead area, replace it as that type problem causes a AC voltage drop to the powerpack which results in erratic, weak, and eventually no ignition.

I retired back in 1991 so there are areas in design on your engine that I'm not familiar with and the above is about the limits of my knowledge in its circuitry, however I'm sure that other more knowledageable members will be adding to it directly.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1

thanks for reply back joe...can i rig my own tester or to i need to by one..be nice if is just the switch...i did notice while it was running the lanyard kill switch connector came off and motor continued to run not stopping motor like it should have...reconnected ran rest of the day till my problem occrred ..could this have any reference to alead on my problem...thanks again joe

Wouldn't know about the kill switch without actually being there BUT pulling the lanyard certainly should have killed the engine.... something wrong there. Here's a tester you can throw together pretty wuick.

(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time.

The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:
　
..........X1..........X2
.................X..(grd)
..........X3..........X4

thanks joe...have spark now found a corroded connections under floor that lifts out where amphenol connection for power connection located....now will start but wont stay running...just put custom built 27 gal aluminum fuel tank in along with all new ethanol resistannt gas lines,filters ,thermostats,water pump.....could carbs be gummed up you think....have had cleaned since bought new in 2002....its a 17ft center console aquasport,,2002 motor,,,1981 boat ..old tank corroded out why had to replace..

Here is a tester that I got from AdvanceAuto, it was cheap and you can set the gap to what you are looking for, in this case 7/16's, if the spark wont jump, then you can reduce the gap until it does jump and therefore have data to use to solve the problem.

i will buy one just to have on hand...thanks joe

joek said:

thanks joe...have spark now found a corroded connections under floor that lifts out where amphenol connection for power connection located....now will start but wont stay running...just put custom built 27 gal aluminum fuel tank in along with all new ethanol resistannt gas lines,filters ,thermostats,water pump.....could carbs be gummed up you think....have had cleaned since bought new in 2002....its a 17ft center console aquasport,,2002 motor,,,1981 boat ..old tank corroded out why had to replace..

Click to expand...

You made the statement in your first post...... "2002 90 hp johnson 2 stroke motor running fine all day til went to make another drift motor started then sputtered and stopped running couldnt get started again...changed spark plugs ....then found had no spark."

If the engine was indeed running normally yesterday, it's quite unlikely that the carburetors would foul overnight. However, drain some fuel from the float chambers to make sure that somehow they aren't being loaded up with oil for some reason (it happens).

Does the engine continue to run if you pump the fuel primer bulb, acting as a manual fuel pump?

Does the engine continue to run if you push the key in at quick intervals, activating the fuel primer solenoid?

no it does not keep running ...even giving a little throttle starts and then quits...gonna go get spark tester to check each cylinder for proper spark...meant to say have not had carbs cleaned or serviced since i bought new..drained the bowls on all 4 seemed real clean...only on 4th tank since installing new one...thanks 4 your help really appreciate this...need to get running ...get back on the ocean...joe

bad power pak...brought to the marina..had diagnostic test done on elec system..found to be bad power pak..total cost..625.00

joek said:

bad power pak...brought to the marina..had diagnostic test done on elec system..found to be bad power pak..total cost..625.00

Click to expand...

To avoid a repeat in case voltage is present at the black/yellow kill wire..............

Turn battery switch to OFF. If no battery switch, temporarily remove cables from positive battery terminal.

1 - Remove black/yellow wire from ignition switch "M" terminal and get that wire out of the way.

2 - Turn battery switch to ON or connect cables.

3 - Turn the key switch to the ON setting.

4 - Set volt meter to a setting whereas it would register even a extremely low voltage.

5 - Connect the volt meter between that "M" terminal and any ground.

6 - If any voltage is present at that "M" terminal, replace the igniton switch.

Voltage applied to the black/yellow wire via that "M" terminal indicates a shorted ignition switch which will destroy the powerpack. Make sure that there is absolutely no other wire attached to that "M" terminal.

When connecting the wire(s) back to the ignition switch, have the battery switch turned to OFF or disconnect the cables from the battery again to avoid an accidental shorting of the switch.