Trim Swith down keeps breaking

[snagroms]

Single lever binacle shifter trim/tilt switch has broken 2 times in 5 hours of use. The trim down is broke while trim up is just fine. Motor is a 1978 Evinrude 175. Trim/tilt is wired exactly to the Service Manual and is using standard harness. Both failures have occured when triming fully down. After the failure I can disconnect switch and jump the connectors in the harness and tirm/tilt works fine. What can I check to track the problem down? Could it be 2 faulty switch assemblies?

 

[SuzukiChopper]

Re: Trim Swith down keeps breaking

Do you have any relays in your circuit?? I don't think those switches are rated to handle the current draw through a T&T pump under load. On mine when I reach full down or full up the current draw can be upwards of 30 amps, you'd need a pretty big heavy duty switch to handle that. I would double check the diagrams and see if they mention anything about relays.

 

[snagroms]

Re: Trim Swith down keeps breaking

There is a rely or soleniod in the tilt wiring box on the back of the motor. My understanding is the solenoid is used for power in the up mode but not down. The manual shows 29amps in full down trim mode. The power side of the trim circuit has a 30amp fuse in it that is not blowing. So I'm assuming I'm not drawing more than 30amps when trimmed fully down. The switch is a BRP switch 176532(thumb style)that mounts into the handle of the shifter. I can not find any thing in its documentation referencing max amps ratings. Documentation shows that the switch is designed to work with this motor. Any thoughts.

 

[Cricket Too]

Re: Trim Swith down keeps breaking

I have one that always breaks a wire inside the binnacle, I have spliced it 2 times already, it's just in a bad position where it puts pressure on the wire when you move the throttle. Try pulling it apart and checking the wires.

 

[snagroms]

Re: Trim Swith down keeps breaking

I've pulled and check contiunuity through the wires. No breaks in the wiring and no continuity in the down position. Same check was done on the previous switch that broke. My thought was a pinched wire as well. No such luck! This switch broke while is was in the driveway. Just trimmed down to fill LU after waterpump replacement. No movement of the throttle when the switch died.

 

[SuzukiChopper]

Re: Trim Swith down keeps breaking

Is it a two wire or three wire pump for the T&T? I assume that you have checked continuity between the feed on the switch and the down pole on the switch as well as the wires from the switch to the unit? If there isn't any continuity in the switch itself then yeah it's bad, but something has to be causing that. Is the switch more difficult to push into the down position then the up position? When you jump the wires to put the motor down do they spark or get hot? It really seems to me that that current rating on the swich is being exceeded. Most switches that size usually can't handle anymore than 10 - 20amps.

 

[snagroms]

Re: Trim Swith down keeps breaking

Suzuki,<br /><br />The unit is a three wire and the trim switch is used on many many setups. I assume BRP has it engineered to handle numerous tnt motors hooked to it. It feels as if the mechanical feel in the switch is gone in the down mode. Up mode you feel the slight click while nothing on the down mode after it fails. Yes when I jump the wires I am getting some sparking.....<br /><br />I just tore the 1st failed switch totaly down (removed potting and acutal switch)to check on the mechanical feel aspect and may have an idea on what is going on. The + feed runs through center of the back plastic body and is connected to a thin metal cover with 2 convexed (3/8") areas. When the switch is depressed the convexed area touches a contact point below (either blue or green) and completes the circuit. I peeled the thin metal cover back and it was fairly well arched. Kinda like points going bad. Hmmm.... The thin metal is kinda erroded over the contact and was no longer able to touch it. Definently arching related.<br /><br />I've torn into the power supply side now and found very loose + and - lugs. These lugs connect to the + starter soleniod post and motor ground post instead of going directly to the battery. The loose lugs are a problem but is it OK to run from the motor versus cables directly down to the battery?<br /><br />The harness had 3 butt connectors on the red/green/blue wires. I removed them and found the red lead to be only connected by about 1/2 the wire strands. All 3 butts are gone and replaced with ring terminals and direct connections. <br /><br />Do you think these power feeding issues are causing the arching problems?

 

[SuzukiChopper]

Re: Trim Swith down keeps breaking

Most definately could be the problem. I would make sure that all your connections are CLEAN and tight. Glad you replaced the connectors as well. That relay in the circuit should be providing a connection in both the up and down positions. It's most likely a DPDT relay and is activated in one of two directions from the switch. Make sure all the connections on it are good tight and clean as well.<br /><br />As for the connection on the solenoid and engine ground, as long as they are both tight and clean, there is no problem doing this. The + should be connected together with the feed straight from the battery anyways, and ground is ground is ground as long as it's tight and clean. See if you can replace those loose lugs, or tighten them in any way. Let us know how you make out!

 

[snagroms]

Re: Trim Swith down keeps breaking

Most definite yes on all connections. The relay is only used for trim/tilt up. Not a dual position type. Green circuit goes straight from switch to trim motor. I'll post back but will be a while since I'm rewiring the boat.

 

[SuzukiChopper]

Re: Trim Swith down keeps breaking

Good luck