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2005 4 Cycle 75HP 4 cylinder Merc Crank but no start

adudinsk

New member
I have a 2005 (SN 1E000385) mercy 75HP outboard (4 cycle/4 cyl) I am told it was made by Yamaha
This is what was done.
1) New plugs
2) Oil
3) Impeller
4) Lower end seals

Engine started first crack
but had a "cough" would run ok..and every and then a sputter (single)
Did not charge battery.
Found rectifier was blown out (literally burnt up ), replaced it..
Started engine,.. checked charging system.. 13.5V tested fine
Engine started in one crank!

THE PROBLEM
----------------------
Came back 3 days later.
Crank but NO START
I spray some starting fluid in the carb intakes..
Engine starts up for 1-2 sec.. dies

WHen cranking engine does have the occasional sputter

Strange that this happened all of a sudden.

DIAGNOSIS
1) pulled hose from fuel pump.. LOTS coming out.
2) Put a timing light on each wire. I THINK #4 is not firing..
The engine has dual (wasted spark) coils.. how could 1 die? I guess anything is possible

(would one bad plug cause a total no start.. or just a rough idle)
Coil packs no longer made... ordered a used one and also a "replacement one"

Could it be the CDI unit?
Any test procedures?

If the kill circuit is stopping the engine, would it still fire up for a few sec on the starting fluid spray?
If the kill circuit is stopping the engine would I get a spark trigger on my timing light?

Its soo strange that it fired fine.. then nothing three days later.

Thanks in advance
AD
 
Sort of late to the party here and I can only suggest two things, since you have had a serious electrical problem have you carefully checked all of your fuses? Voltage spikes can do some weird things. The other is to invest in a shop manual, even if this is the only time you use it it would be money well spent as they can be had download versions about $15.
 
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