Carb / Tach Problems

I don't know if these 2 problems are related but here goes.
1. The Tachometer (Rev Counter) on the dashboard stopped working for no apparent reason, what/where should I be checking, and where/how is does the gauge get its reading from the engine?

2. The following week after the above problem appeared, the engine developed the following symptoms. When pulling out a skier it seems very sluggish, it then picks upand runs okay but when you require extra power to get into 30/32 there is non to be had. Then the engine will deliver the extra power but in an on/off state so it appears that the driver is playing with the throttle.
Any ideas?

The boat is a 92SN with 285hp electronic ignition, and a holley carb (2 seasons old) fitted by the dealer.

Please give any suggestions is basic laymans terms, I am learning but have a long way to go before I am classed as a mecahnic.
Thanks

I tend to agree- most likely an ignition problem, especially since the wire to the tach comes form the coil as mentioned and would cause the tach to stop working. Check the wires coming into the coil to ensure they are intact and making a CLEAN connection. Then check to see if the plug wires are in tact ie arching and in need of replacement, easy way to do this is to run the enign in the dark or feel the wires.

I think '79 is on the right track. On our older boats, these would be separate issues since the tach gets its signal from the distributor. On the later boats, I think everything comes out of the ignition module. Not much that can be done to repair the modules, except replacement. Just need to make sure that the mod is the problem before spending the bucks on a new one.

Hey IrishFooter, you forgot to tell him to put a mattress on the floor behind himself when he does the wet test on the plug wires. How many volts are running through those electronic ignitions????