Tilt / Trim Limiter???

bighermHK45

Petty Officer 3rd Class
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Jun 17, 2012
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Is there a way to limit the tilt travel on my 1999 Mercury 115 ELPTO? I am trying to figure out the best way when I am raising it up to get it to stop before it hits my sundeck.
 

Texasmark

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Blue sky, Green water. Go to your trim relays and find the small diameter blue wire which controls your up relay. Interrupt it with a spst nc (that's single pole...one electrical circuit to interrupt, single throw, meaning it's off or on, nc meaning it's normally closed) switch. Current rating of 10 amps is plenty as this is a control wire, not a drive wire for the motor in the pump.

Mount the switch on a bracket on one of your engine's transom mounting brackets and mount a second bracket on the engine cowl so that when you reach your desired position the bracket on the engine (or you can put the switch on the engine and the control bracket on the engines clamp bracket...whichever works for you) depresses the switch. This will open the drive power to the up relay via the "now open" blue wire and stop motor drive in the up position.

To go down, the small green wire gets power from the trim switch and the blue wire is unused so it matters not that the switch is in the circuit.

That would do it for me.

Mark
 

bighermHK45

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Thanks for the reply. I have a trim switch mounted on the outboard already. Unless I am misunderstanding your post, I am looking for something that mechanically stops the outboard from tilting to the full up position. Specifically, when using the tilt control at the helm, I am concerned when other folks are using the pontoon that they will tilt the motor all the way up and that would damage the cowling or sundeck (or both). I wasn't sure if something existed that would prevent full tilt.
 

Texasmark

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Once you wire the switch into the blue wire going to the up trim relay, under normal circumstances they can't get it up any farther than you can. Otherwise rather than have what I said, just make the brackets tougher and omit the switch. Have never heard of such from any boating source of info so you are blazing uncharted territory here. On how strong to make the brackets, I don't know the amount of resistance it takes before the pressure relief valve in the trim pump gets knocked off it's seat and stops upward/downward movement.

Good luck,
Mark
 

Texasmark

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The page won't open so I went to the site looking around. Wound up in the Accessories section and dug around a bit. Then figured it'd be in the switch section and there were probably 50 there. So, where on the site is what you want to show us?

Mark
 

bighermHK45

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The page won't open so I went to the site looking around. Wound up in the Accessories section and dug around a bit. Then figured it'd be in the switch section and there were probably 50 there. So, where on the site is what you want to show us?

Mark
[h=1]87-814407A 3 - TILT SWITCH KIT
Kit includes a mercury switch to limit power trim travel and a new, shorter tilt bracket
[/h] It is located on the marineenginedotcom website.
 
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Texasmark

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I pulled it up. First of all I don't know why a mechanical/manual tilt bracket shortening would be part of it. The tilt bracket is for locking the engine in the up position when pressure is not desired on the PTT to hold the engine up....not to be used in trailering as it may be too fragile to tolerate road bumps and all. A LU to trailer bar, separate after market item is used for that.

The mercury switch is a ball of mercury that rolls around inside a sealed glass envelope. Included inside the glass envelope are a pair of contacts which the ball shorts out if you tilt the appropriate end and opens in the reverse. Accuracy is somewhat questionable. Your whole tilt range is like -4 to + 15 to 20 out of a 360 degree circle. The difference of a couple of degrees could make the difference between hitting the cowling on the boat, and not being able to lift the LU out of the water when moored.

That switch is naturally grounding something through the mounting bracket (and having only one lead) when closed. Question is What? You can't put it in the PTT control or power ground as it would affect both up and down equally. Once you tilted the engine up the switch would open totally disabling your PTT motor and you couldn't make it come down. What you want is an isolated (from ground) series switch that you can put in the blue line (12v when going up) that opens that circuit when tilt reaches a certain height. A SPST of the type I mentioned is much more accurate (opinion) and if you use a slotted bracket you can tweak it to exacly where you want it. Accuracy on that depends on the spring inside the switch and that would have to be tested to be determined. A sealed switch would be desirable in my thinking this through and such is available.

The Mercury switch may be a better solution since it's naturally sealed, but you don't want one that grounds. You could use the switch you mentioned if you isolated the switch from the bracket and attach a separate lugged wire to the the insulated screw (like nylon which is readily available) and touches the switch tab which is now under the metal screw. To complete the installation you would need an insulating washer between the body of the switch and the bracket shown; anything plastic, rubber, or mica are options.

Since you are looking at a hundred bucks here on the switch you mentioned, and would have to do the mods mentioned to do what I think needs doing, surely you can get what you are looking for with a little digging around for around $20. However, if you cobble up your own design, the question still remains as to why the shortening of the tilt bracket?

Stay in touch.

Mark
 

Dukedog

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have seen this done with a "mercury switch" ona V6. built a bracket that mounted under bottom starter bolts with tha switch mounted to it. made it "angle adjustable".. it would drop tha up circuit where ever he wanted it....up n down are two different circuits so tha down circuit is not effected.....was a pretty simple deal.. shoulda taken some pictures but was a long time ago......
 
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Texasmark

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have seen this done with a "mercury switch" ona V6. built a bracket that mounted under bottom starter bolts with tha switch mounted to it. made it "angle adjustable".. it would drop tha up circuit where ever he wanted it....up n down are two different circuits so tha down circuit is not effected.....was a pretty simple deal.. shoulda taken some pictures but was a long time ago......

Yes! No reason the bracket couldn't be under the cowl and the mercury switch and a bracket would be perfect. It's raining outside and with nothing to do I might just www and see what I can find.
 

Texasmark

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Spent some time on the www. First of all, I forgot about it but if I didn't mention it above, a mercury "tilt" switch is a ball of mercury in a sealed glass envelope. A Single Pole Single Throw (SPST) switch will have 2 contacts (this is what you'd use) that are hermetically sealed to the glass and protrude inside to contact the mercury ball. However, the subject of vibration came up in some of the ads and that is a point to consider. Boats do a lot of bouncing around and if the tilt angle where the mercury starts to move in either direction (either open or closing) is close to the switching angle, it can and will bounce around and make and break etc. as you bounce across the waves. So, maybe that's not such a good idea after all.

Other thing is most I saw for sale had no current specified. I got the feeling that most were low current for electronic "sensor" circuits where currents would be in the less than 50 milliampere range. Shooting from the hip I am anticipating your trim relay will run on about 200 milliamperes and I was looking for at least a 1 ampere rated switch.

Requires more thought.

Mark
 

bighermHK45

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I appreciate you looking into this more. I am trying to find examples of the mercury switch used with an outboard, but I am not having any luck. I will keep researching.
 

Dukedog

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won't "bounce around" there any more than it does when its used by production Merc as an ign. kill when tha motor is trimmed up.....
 

Texasmark

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Well sir that depends upon the design of the particular switch. However, since you mentioned it, what about the kill switch you are talking about? Have any OEM part numbers? Going to bet it is a single lead device with the bracket grounding the other terminal. But that could possibly be a solution by isolating the second terminal from the bracket as I mentioned earlier and using it as a "series" switch for powering the up trim solenoid drive circuit.
 

Dukedog

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its tha plain 'ole mercury switch that grounds tha ign. when trimed to high... he simply turned it upside down and used it as a constant ground for tha up solenoid that would disable when trimed up to high.. its just a single pole (on/off, in/out) switch.... don't know tha year of your kids motor is but it probably has/had one on it....maybe 91 or 92 was last year they used it....

best I remember it has a single wire that goes ta ground on one end and a terminal on tha other that ties inta tha "kill switch circuit" that goes to tha switch boxes...single pole switch tha makes or breaks a ground or what ever ya wanna hook up to it.....
 
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