L200TXRS fuse issue

[mustangsqd]

HI Everyone! I have twin 200 Yammies, one is running great, the other is making me pull my hair out!

There are 2 fuses on the port side of the engine, a 20 amp and 30 amp.
The 20 amp controls the tilt motor, among other things.

I kept blowing the 20amp, and I noticed there was an internal continuity problem in the fuse holder itself, as when I wiggled it I would get intermittent power, ie, the tilt motor would function and the ignition buzzer would activate.

Figuring the contacts were dirty, I cleaned them and compressed them to make sure they "gripped" the fuse firmly. This helped for a little while, but now when I run the engine, the 20amop fuse keeps blowing, whether I am at WOT or not.
Sometimes it will run for 10 minutes, or it may run for 1/2 hour w/ no issues.

What load(s) or device(s) does the 20amp fuse control on the motor so that I can check for shorts? Is there a temp switch or thermo switch in the loop,
that could blow the fuse?

Thank you for any ideas!

[gtreanto]

has to be a short to ground issue.

So if there is a switch inline then it has to be bad. unless you can trace the wires you need a wiring diagram to figure this out. Bad tilt motor maybe? 20a is a lot of current, could it be a bad tilt motor? IE winding shorting to ground?

[boscoe99]

Power is supplied through the 20 amp fuse to the engine mounted trim/tilt switch and to key switch through the ten pin harness. Via red wires.

If the red wire to the trim/tilt switch is chaffing to a ground source then that could cause the fuse to blow. Inspect the wiring from the trim/tilt switch back to the connector and on through the engine harness to the fuse for signs of any distress. The switch can be disconnected at the connector to remove the part of the circuit from the connector to the switch itself if you wish.

Same thing for the red wire that runs through the engine harness to the ten pin connector at the front of the motor, through the ten pin harness up to the helm, and then from the key switch on to the gauges.

[boscoe99]

So if there is a switch inline then it has to be bad. unless you can trace the wires you need a wiring diagram to figure this out. Bad tilt motor maybe? 20a is a lot of current, could it be a bad tilt motor? IE winding shorting to ground?

A switch normally fails open or closed. If it fails open the switch simply will not work. If the switch fails closed then the device that is powered by the switch will simply operate uncommanded by the operator. A failed switch does not normally blow a fuse.

If the tilt motor were defective the problem would manifest itself if and when the trim system was activated. This is not what is being reported.

[gtreanto]

It is kind of a strange issue since you would think

power wouldn't run to the tilt motor until the button is pressed. But he is saying the fuse blows when the engine is running and not when he is doing tilt.

[99yam40]

T&T motors usually pull more than 20 amps so they do not run off of the fuse, just the controls should be on the fuse.
this is why high current devices have relays

[gtreanto]

what is the typical current for the control side of the

relay? In cars I expect to see approx 1.5a..

[99yam40]

never had a reason to measure it, so I do not know

[boscoe99]

I measured the current draw to a V6 trim and tilt motor one time and as best I recall it was about 35~40 amps. Strange as it may sound it was more current coming down than going up.

I would not expect the control circuit of a relay to draw more than one amp.

Where is that fairfax fellow? He can measure the ones in his F200 and let us know what he sees.

[99yam40]

I do not think it really matters to the OP.

since the T&T motor does not get its power from that 20 amp fuse, but the controls do

[boscoe99]

I do not think it really matters to the OP.

since the T&T motor does not get its power from that 20 amp fuse, but the controls do

I agree with you.

This thread is evolving. As so many do.

[gtreanto]

it just seems like 20a is a lot of fuse for control.

this circuit must be used for something more.

[boscoe99]

this circuit must be used for something more.

For the engine mounted trim switch. For the throttle handle mounted trim switch. For power to the motor. For power to the gauges. For anything else that needs power from the key switch up at the helm.

[mustangsqd]

Thank you for the ideas gentlemen! To clarify, as gtreanto stated,
the problem occurs when the engine is running, not when operating the T/T switch, ( either at the engine or the helm position)

Any ideas on what else may be powered from this circuit?

If this circuit is powering the keyswitch, I suppose that a device activated by the keyswitch could be overloading the circuit causing the fuse to blow as well?

Thanks!

[zenoahphobic]

I'll go with something (wire or terminal) is ground down, loose or rattling creating a short with the vibration of the running engine. This could also be in the inside of a switch. Inspection and movement of wires at terminals should expose the fault.