Had an issue with my starting battery checking accessories the biggest current draw is my Lowrance X135
sonar. Disconnected power source at the sonar & the wire direct to the battery is fine. There is enough draw
to create a faint spark at the battery. Spark at battery with sonar hooked up is intermitent is this normal?
There is no GPS with this sonar.

I'm a little puzzled by what you meant by "Spark at battery with sonar hooked up is intermitent" ??
But, in a general answer - yes, a faint spark if the unit was on would be normal. While the unit doesn't draw a big amount of current, it does pull enough to do what you saw. If you are concerned, you really should get a multimeter, and measure how many milliamps it is pulling, and compare to what your manual says it is rated for. But, if there was really something wrong - you would know it, as the unit would let out a bunch of smoke, and stop working......

Intermittant spark may be partially caused by the moderate increase in power needed by the transducer to create the "ping" needed for the sonar. May not be regular, as I am sure there are capacitors inside the unit that act as short term batteries to run the transducer - and they will pull more current, but less frequently, than the transducer will use for a given amount of time.

The spark that I am seeing from the sonar is very faint it occurs with the sonar off & it does not happen every time that you touch the positive feed from the sonar to the positive post on the battery. Tested with a
multimeter & it registered 1.8. What I see is that the sonar is drawing a small amount of current even while it is off.

OK- I'll bite. When the multimeter registered 1.8, what were you measuring and what was the scale?