Cobra Trim Sender

muc

"Retired" Association of Marine Technicians...
Joined
Jul 7, 2004
Messages
2,170
Part number 984748 supersedes to p/n 3850470 both are NLA. Any good ideas? Thanks MUC
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Cobra Trim Sender

Learn how to FEEL where the drive is at, how it sounds, how it acts, speed vs. RPM, how the boat handles, etc.
Once you get used to it, the gauge is a usless item on the boat simply because the trim changes constantly.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,079
Re: Cobra Trim Sender

Learn how to FEEL where the drive is at, how it sounds, how it acts, speed vs. RPM, how the boat handles, etc.
Once you get used to it, the gauge is a usless item on the boat simply because the trim changes constantly.

Ayuh,.....

The "Seat of your Pants" is a much Better, more reliable Trim Gauge......
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,023
Re: Cobra Trim Sender

Those trim senders tend to not last too long....I've replaced mine twice...I agree that trimming by feel makes more sense, but at times it is good to know how far down the drive is, so I timed how long mine takes to go from full up to full down, about 12 sec, so time yours, and then if you're full down, and need to trim up because of shallow water, I will trim up for about 6 sec and that's about 1/2 way up, far up enough to be safe.
 

Slip Away

Lieutenant
Joined
May 11, 2010
Messages
1,431
Re: Cobra Trim Sender

The part number is:18-7634 It is for all Cobra models 1986-1993. Retail is $154.00, but on line you can get it for about $102.00.
I thought that was a bit much for a switch, so I tore mine apart. The casing is filled with silicon and can easily be taken out. Inside the switch is an
AB (Allen/Bradley) potentiometer. The poteniometer is wired with a small resistor between the terminals. The part number of the potentiometer is not
traceable because AB was sold to Rockwell and Rockwell did not keep any records on poteniometers used on particular customer orders like OMC.
However, after testing resistance values on the trim gauge (as my poteniometer was shot and not testable) I found that a $2.99 1K ohm resistor from
radio shack worked just fine. You do not need the additional resistor AB put on theirs. I notched the the potentiometer shaft to accept the tilt lever, attached two new wire leads, filled it with black silcon from Home Depot and respliced the wires. WORKS GREAT!!! Total cost of repair: $4.89 which included the silicon.
 

zbnutcase

Commander
Joined
Sep 19, 2009
Messages
2,055
Re: Cobra Trim Sender

The part number is:18-7634 It is for all Cobra models 1986-1993. Retail is $154.00, but on line you can get it for about $102.00.
I thought that was a bit much for a switch, so I tore mine apart. The casing is filled with silicon and can easily be taken out. Inside the switch is an
AB (Allen/Bradley) potentiometer. The poteniometer is wired with a small resistor between the terminals. The part number of the potentiometer is not
traceable because AB was sold to Rockwell and Rockwell did not keep any records on poteniometers used on particular customer orders like OMC.
However, after testing resistance values on the trim gauge (as my poteniometer was shot and not testable) I found that a $2.99 1K ohm resistor from
radio shack worked just fine. You do not need the additional resistor AB put on theirs. I notched the the potentiometer shaft to accept the tilt lever, attached two new wire leads, filled it with black silcon from Home Depot and respliced the wires. WORKS GREAT!!! Total cost of repair: $4.89 which included the silicon.

Nice work! Although I would never do that on a customers boat, too labor intensive.
 
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