Shift interupter

[cooter2506]

I adjusted my shift cable as per manual. 6". But when i shift (engine not running) Switch does not activate. Am I missing something. Engine is a 98 5.0 mercruiser.

 

[SuperNova]

Re: Shift interupter

The switch only activates coming out of gear with the engine running. There has to be enough force holding it in gear to cause the rocker setup to overcome spring tension. It won't activate just sitting in the driveway. If you didn't fool with it during the cable replacement, there should be no reason to fool with it now. If it worked before it'll work again if the cable is adjusted properly.
--
Stan

 

[Haut Medoc]

Re: Shift interupter

It is barely perceptible anyway......
1/8" is all it needs to move to activate for a fraction of a second.....​

 

[cooter2506]

Re: Shift interupter

OH ok I thought it would activate just by moving throttle didnt know engine needed to be running, thanks guys

 

[Darol Wester]

Re: Shift interrupter

Re: Shift interrupter

On a 78 mercruiser, we're having a similar problem. The boat has always ground a bit going from one gear to another. We've adjusted the cable according to the Merc manual, 6", and the interrupter just sits there and the gears grind. No movement at all. Any ideas?

 

[Darol Wester]

Re: Shift interupter

OK. I did a search of the archives and found this great piece of information from Boatin Bob.

http://www.homestead.com/dolphinmarineservice/Cable.html


Thought I'd post it again. Thanks Bob

 

[qystan]

Re: Shift interupter

Try this

http://forums.iboats.com/showthread.php?t=158082

 

[Darol Wester]

Re: Shift interupter

Great info. Thanks!

 

[gogodiablo]

Re: Shift interupter

If I understand the info in the two links posted, The shift interupter ONLY activates when one shift cable moves and the other does not... is this correct?
Also, is it usually the lower shift cable that does NOT move when the upper cable moves to create this condition?

 

[qystan]

Re: Shift interupter

If I understand the info in the two links posted, The shift interupter ONLY activates when one shift cable moves and the other does not... is this correct?
Also, is it usually the lower shift cable that does NOT move when the upper cable moves to create this condition?

Yes.

 

[Darol Wester]

Re: Shift interrupter

Re: Shift interrupter

We've adjusted the linkage to all of the specs listed above and it does improve it a little maybe, but it still grinds pretty good going IN to gear, both forward and reverse. This is done with the boat on the trailer. Should it function better in the water?

There seems to be too much resistance due to the tension of the spring rods at each side of the shift plate that operates the switch. Can those rods/springs get stiffer with age? You can see the upper cable moving first but it won't move the plate.

 

[SuperNova]

Re: Shift interupter

The shift interuptor is not designed to stop the grinding going into gear. It's supposed to help disengage the gears when there is a load on them, such as when the boat is IN THE WATER. The grinding is fairly normal. You are not supposed to ease these things into gear. It should be one smooth, swift movement to go from neutral to drive or reverse. They are dog type clutches and need to be engaged with a firm, strong action. So quit pansying around with the gear shifter and start manhandling it.
--
Stan

 

[Don S]

Re: Shift interupter

What is your actual problem? Just the grinding going into gear?

 

[Darol Wester]

Re: Shift interrupter

Re: Shift interrupter

That's correct. In the water it wasn't so bad but on the trailer it sounds a lot worse. I just assumed that the interrupter would mellow the shifting problems. Wrong assumption on my part? Only coming out of gear? My apologies.

Why don't they have sinkros in these puppies?

 

[Don S]

Re: Shift interrupter

Re: Shift interrupter

It's a dog clutch, you aren't meshing gears so syncros won't work.
When you shift gears, put it in gear like you mean it, not a speed shift, but so there is a single clunk as it goes in. Out of the water will be worse just because the water isn't there. Also make sure your idle rpm is at the proper speed for your engine.

 

[Darol Wester]

Re: Shift interupter

Thanks Don. By the sound it makes you would think the gears in the lower unit would be taking a real beating. What does this do to the life of the gears or are they just built to take it?

Again, thanks to all! The boats back in the water tomorrow and with any luck, we'll be in the middle of some Tuna and Salmon before too long. Happy days are here again.

 

[Don S]

Re: Shift interupter

You should really appoligize to Cooter2506 for hijacing his thread for your problem.

That is why you should ALWAYS (even if the problem is similar) start a new thread with your own question.

 

[Darol Wester]

Re: Shift interupter

I never concidered I was hijacking a 2 month old thread. But....My opologies Cooter. It wasn't my intention.