1973 Mercruiser 165HP- 2 shift interrupters? One for forward and one for reverse???

[theck4291]

Started a new post as the last one was figured out, which was boat dieing going into reverse... had to adjust the shift cables at the shift plate, and it now works, however I am now going to be also changing my impeller just to be safe.....

My QUESTION is this, I think my boat has 2 shift interrupters, one for forward and one for reverse... if so the one for reverse is disconnected.... how do I connect it? I am going to attach a stock photo of the switch I need connected... any help is appreciated!

 

[Alumarine]

You should only have 1. It should look like the one in the above picture.
Can post a picture of both your switches.

 

[Fishermark]

You mentioned in your other post that you had two switches... there should only be one. Someone obviously modified your setup at some point in the past. The simple way to determine which one to use is the one that has the shift and control cables hooked to the shift plate.

 

[theck4291]

fishermark I agree with you, and I DO NOT remember unhooking the one that is unhooked, but when I spoke to my fatherinlaw, who i bought the boat from, he said that it should have both hooked up.... I am off to work, at 7am when i get home will be working on the impeller, then going to figure this switch BS out.... it just didnt seem like the one that IS hooked up and working was moving at all when I got it into reverse... but it had to be right? if it was previously killing the boat?!?! just kill me already lol... SOOOOO CLOSE to being done, but still feel so far away!

 

[Pete104]

You only have 1 shift interrupt switch. It momentarily kills the ignition to get to neutral.
The switch you are referring to is wired in to trim system. That switch "opened" by the "reverse lock valve". It was designed to not allow the operator to "trim up" or "tilt up" while in reverse. Without that switch "closed" you wouldn't be able to raise the drive and because of the reverse lock valve, in some cases, you would have to have the drive in forward gear position, normally because the RLV wasn't adjusted properly. The pump pulled too many amps for that switch & it killed it. So, it was eliminated. The wires that ran to it should be close by with a "butt splice" on them.
Why are you up in that area for an impeller anyway?

 

[fishrdan]

Agree that there should only be one shift interrupt switch, though there are some other switches on the transom assy, trim pump, etc.

That switch you posted up should have the roller located into a V that goes one way for reverse and the other for forward. Post up a pic or two so we know what you are working on, the 2 switches you mention. I have a 73' 140HP that uses the same transom assy.....

 

[theck4291]

No Title

Hopefully the pics I uploaded will help you guys help me!

Pete104- I was not in that area for the impeller, however I was running the engine in short bursts trying to figure everything out and get it running,(very new at boating/working on boats) and forgot to put my muffs on, so I was just saying that I am ALSO going to change the impeller... sorry for any confusion

 

[nola mike]

fishermark it just didnt seem like the one that IS hooked up and working was moving at all when I got it into reverse... but it had to be right? if it was previously killing the boat?!?!!

If you're running on muffs, there isn't enough drag on the prop to trip the shift interrupt switch.

 

[theck4291]

nola mike, the switch is being engaged while going into forward, I can physically see the lever moving, however I cannot see anything in reverse, that is all I am trying to get across and not sure if this is normal

 

[Fishermark]

If it truly is the shift interrupt switch you are looking at, then something is wrong. It should not engage when you go into gear - ever. It should only engage when coming out of gear - and then only when pressure is exerted on the prop (like the water). Anything else is a problem and needs to be fixed.

 

[Pete104]

The switch to the port side is the "interrupt switch". The switch on the stbd side is as I explained in previous post. The reason I think they were bypassed is that Mercury re-disgned the "reverse lock valve" & doing so discontinued supplying that switch.
If it were me, and everything is working like it should, I would leave it alone. I really believe your boat is older than 1973. More like 1967-70. It's hard to tell on those real early units. Regardless of year, that unit is within the first 10 years of MerCruiser being known to anybody.

Change the water pump complete with base, fill it & if it shifts OK and the drive doesn't pop out of the water when you shift to reverse all should be good!

Have fun.