Weak spark Mariner 60 2 stroke

[Dankoozy]

I am after changing the ignition coil which seemed to improve things to some extent but pretty sure it is running on 2 cylinders now. The engine is from about 1998 and uses one of these CDI modules



https://greenbayprop.com/media/mercu...#media-38293-2


Is there anything that could cause a weak spark on one cylinder besides the CDI pack and the coil? any place I can get a wiring diagram for the engine?

[jeffstevens763@g]

New plugs ?

[Allye]

I’ve just been on this adventure. Is it a weak spark or not spark?

There are pickups on the stator under the flywheel which can cause loss of spark on individual cylinders. Are you familiar with a multimeter?

[Turbodiesel]

Don’t forget with CDI ignition the coils earth through each other so a faulty coils on one cylinder can cause a fault in another cylinder if that makes sense!

[davej]

I have only ever had one problem with my old smoky merc 60 2s and that was down to the switch box, the original ones were not great and seemed to fail after some years use. I tested it with a standard multi meter and then had the luck of buying a secondhand one from a friend.

However, if you google CDI dealers Uk there is a very helpful guy I think in the Portsmouth area that supplies replacement CDI stuff from the states. These switch boxes are a bog standard item and the CDI ones are much better than the original merc ones.

It’s a very easy job to replace. Again my dive clubs big Yam had a switch box replaced , we just couldn’t get to the bottom of it’s difficult starting but eventually tracked it down and took an educated punt at it being the switch box, which it was, Oem part from yam dealer 950£ part from CDI man 500£.

I can probably find his details if you can’t find him on the web.

[whiskylee]

Originally Posted by davej

I have only ever had one problem with my old smoky merc 60 2s and that was down to the switch box, the original ones were not great and seemed to fail after some years use. I tested it with a standard multi meter and then had the luck of buying a secondhand one from a friend.

However, if you google CDI dealers Uk there is a very helpful guy I think in the Portsmouth area that supplies replacement CDI stuff from the states. These switch boxes are a bog standard item and the CDI ones are much better than the original merc ones.

It’s a very easy job to replace. Again my dive clubs big Yam had a switch box replaced , we just couldn’t get to the bottom of it’s difficult starting but eventually tracked it down and took an educated punt at it being the switch box, which it was, Oem part from yam dealer 950£ part from CDI man 500£.

I can probably find his details if you can’t find him on the web.

Engine room marine parts, Tim is his name
I've had a few electrical parts from him over the years [emoji106]

http://www.mareng.co.uk/

[davej]

He was really helpful and he told me that Merc parts are considerably cheaper than the Yam bits so for that old merc/mariner they should be ok.