Ignition curcuit problem

[towlerg]

This is not Vega specific as Vista was repowered with a Vetus engine.
Being an imbecile where engines (and many other things) are concerned
perhaps someone can point me in the right direction.

Everytime I crank the engine it blows a 10amp fuse in the ignition
curcuit. The ignition switch is a four potition switch,

off - on - preheat - crank

The fuse does not blow till the crank position. If I disconect the
wire that goes to the starter solenoid, the fuse does not blow, but of
course the engine does not crank.

I measure less than one ohm in the solenoid coil. Does that seem much
to low, I would have thought more like 10 ohms (just over an amp seems
more than enough to switch the starter motor)

What might a typical value be?

BTW its a M2.05, if anyboby has one could they measure the resistance
of the solenoid coil.

Grateful for any info or observations.

George Towler "Vista" 1043

 

[bluenorth50]

It sounds like you have a pretty good handle on what is going on.

From the informtaion you have provided we can assume that the switch
in the crank position is good and the wire from the switch to the
coil is good. By good I mean not faulted, shorted, connected to
ground. Although, by disconnecting the load (coil) the problem can
seem to disappear due to no current flow. It would be great if you
could connect a different 12 VDC coil in place of the existing one
and try the circuit again, if the fuse held and the coil energized
you could focus on the existing coil.

Anyways, in your troubleshooting process you are down to the coil.
You've measured 1 ohm across the coil. Disconnect all wires from
the coil and measure ohms from one coil lead to ground, you should
not get a reading, if you do then the coil is faulted to ground. Try
measuring ohms from the other coil lead and to ground.

I'm not an electrical guru but there is not harm is the above tests.

Good Luck!
Greg