Mercury thunderbolt 402 won't start

Hi,

I have a mercury 402 thunderbolt that won't start anymore all of the sudden. At the end of a day cruising (through the Dutch canals) we stopped, and after that the engine did not start anymore. While using the electric starter, the engine does not make any sound as if it is about to start.

I've did the following so far:
check the spark plugs, both do spark, but I've replaced them to be sure.
When I disconnect the fuel line to the carburetor while starting, the fuel spits out, also when I removed the carburetor fuel was pouring out, so I presume there is no problem with the fuel line.
I've cleaned the carburetor.


Does anyone have an idea what the problem could be, or what I could check next??

I was thinking of the ignition, could the ignition system got broken all of the sudden in such a way that it still sparks, but with completely wrong timing.

Thank in advance!
Ren?

Re: Mercury thunderbolt 402 won't start

I was thinking of the ignition, could the ignition system got broken all of the sudden in such a way that it still sparks, but with completely wrong timing.

Click to expand...

That can happen if the flywheel key shears and allows the flywheel to slip, Rene.

Re: Mercury thunderbolt 402 won't start

Thanks for the hint, I'm going to check that tonight!

Re: Mercury thunderbolt 402 won't start

JB said:

That can happen if the flywheel key shears and allows the flywheel to slip, Rene.

Click to expand...

Does this mean I should be able to move the flywheel without the pistons to move?
The bolt on top of the flywheel is fixed tight, and when I move the flywheel, the pistons move as well. There seems to be no movement between them... Is it save to conclude the root cause is something else?

Are there any other suggestions to check or?

Thanks in advance!

Re: Mercury thunderbolt 402 won't start

The problem turned out to be the ignition coil. part of the coil was burned/shorted, causing the sparks to be to weak...
we found out by checking the coils for the ohm's resistance as specified in the manual.