Logo
FULL SITE MENU

1995 150 johnson fast strike For Joe Reeves

C

Converter

Guest
"I have the above outboard. B

"I have the above outboard. Bought boat, motor, trailer for $700. Rebuild carbs, removed VRO per Joe's instructions from this forum, and replaced waterpump. Here is the problem: Engine fires sometimes then dies. Will not fire again. Wait for a while and engine will fire, run rough, then die. My Question-Do you think the powerpack is bad. I am a Mercury Man and this is my first Johnson. I am asking for help.

Thanks"
 
"Remove spark plugs. Check com

"Remove spark plugs. Check compression... what are the readings?

Plugs still removed, connect a spark tester where a 7/16" gap can be set. Spark should jump that gap with a strong blue lightning like flame... a real SNAP! Does it?

Did you have the flywheel off? If so, when replacing, did you torque the flywheel nut to factory specifications? If not, the flywheel key is probably sheared somewhat which throws the engine out of time."
 
"Flywheel torqued to spec in S

"Flywheel torqued to spec in Seloc Manual. Compression is 110-115 in each cylinder. Intermitant(Sorry for spelling) spark, then none. I had an older Mercury that did this and it was the ignition module. Previous owner stated that he had to replace the power pack before. He replaced it with a used one.

Thanks"
 
"Remove black/yellow wire that

"Remove black/yellow wire that leads from engine wiring harness to powerpack (kill circuit). If unsure as to which black/yellow wire, disconnect the black/yellow wire from the ignition switch.

Remove spark plugs.

Test spark. If you now have proper spark, the usual cause is an intermitent short within the ignition switch, in which case, replace it."
 
Will Try that this afternoon.

Will Try that this afternoon. Will let you know the outcome.

Thanks
 
"Well Joe, tried your wire tri

"Well Joe, tried your wire trick. Had yellowish spark on all plugs. Motor ran better for a short while then died. Upon retry, no spark. Could the power pack or other ignition systems be going bad due to heat? Again, I am an old Mercury Owner and this is driving me crazy. Please give me guidance from your vast expanse of Knowledge.

I have been humbled."
 
"Update- Ran motor. Ran great

"Update- Ran motor. Ran great for about 2 minutes then died like switch was cut off. Checked spark, none.

Any Ideas?"
 
"If this test run is being per

"If this test run is being performed with the black/yellow wire disconnected, I would suspect a melting down stator under the flywheel (beginning of the charging and ignition system).

Visually check that stator to see if the black coils are leaking a substance down upon the timer base and powerhead. If so, replace that stator.

Those black coils emit approximately 300 AC volts to the powerpack capacitor in order to energize the ignition. When those black coils start to melt down, a AC voltage drop occurs resulting in weak or no ignition.

Another problem that may exist if that black/yellow wire is connected is that perhaps a slight short might exist in the ignition switch, and if so, that would allow a very slight amount of DC voltage to be applied to that black/yellow wire. This, in a short time would dasmage the powerpack.

To test for this type problem, disconnect that black/yellow wire from the powerpack.... the one that leads from the engine wiring harness if there's more than one, then connect a volt meter red lead to that engine harness black/yellow wire with the meter's black lead attached to a powerhead ground. Have the meter set to its most sensitive DC reading. Turn the key to the ON position. If there's the slightest reading on the meter, even a milivolt, disconnect the black/yellow wire from the ignition switch.

If the voltage draw vanishes, replace the ignition switch. If it does not, there is a short of some kind in the wiring harness somewhere."
 
Back
Top