3.0L Mercruiser Shift Interrupt not working.

[Topvader1]

I have a '05 Four Winns with the 3.0L Mercruiser motor with the "new style" shift interrupt switch (Motor SN 0W039120). Bought the boat last year and the previous owner stated that he just put a new shift interrupt switch in it. When I had the boat winterized last fall they stated that the switch wasn't working and asked if I was having any issues; I said no. Fast forward to this season, and now I am sort of looking for it, and yes, I am in fact noticing a 3-5 second delay in the prop coming out of gear when shifting into neutral. Figuring the old owner was full of it, I bought a new switch, installed it and motor does not cut out or stall when pressing the brand new switch. Assuming I don't have two bad switches, I called the marina that winterized it and they said it could be out of adjustment, or could have been disconnected ect. ect. They weren't sure and they would have to diagnose it and may have to pull off out drive to re-adjust, and also mentioned I may have stretched out the shift cable if I don't take care of this issue (then I would definitely need to pull out drive).

Anyone have insight? Is there a way to "re-wire" that shift interrupt switch back into the system? Why would someone purposely disconnect it? Should I bite the bullet and let the marina shop diagnose it? Or are there some steps I could take to trouble shoot it myself?

 

[alldodge]

Hey Top your posting is making it, you now have 4 threads going

If the switch is not killing the motor when pressed then you probably have a wire not making connection. Check the Whit/Grn wire which goes to the distributor and the other which goes to ground. It could be you lost your ground connection, or the connector going to the distributor is not good

 

[Topvader1]

I feel like an idiot - after I would hit "post" it was giving me an error message - I sent a note to the forum admin to let them know of my issue and copied the error message. I then come back into the forum and see 4 threads going, so I sent anouther trouble ticket because I cant delete them! Ugh, newbie and I feel stupid to boot!

Anyway, sorry for cluttering up the forum, and thanks for the response. Am I safe to run a new 16 guage wire directly to the white/green wire coming out of the distributor, I could zip tie it to the harness so it looked clean. On the same note - I could then run a new ground wire and tie it into the coil right? This should cut any issues with the factory harness correct?

Other than cutting the wire, is there any other way to quickly disconnect this switch other than un-plugging it up by the switch? I just want to make sure that I am not overlooking a common way to take the switch out of commission that a previous owner have have done.

 

[alldodge]

Try this first, disconnect the two wires going to the switch (wht/grn and blk). With the motor running, touch the two wire together and see if it dies.

If touching the two wires together does nothing, touch the wht/grn wire to a good ground, engine should die.

If this does not kill the motor, disconnect the plug on the distributor with the wht/grn and 2 white wires. Note which pin the wht/grn wire is attached to. Now take another wire and jump from ground to the position where the wht/grn wire was on the distributor pin.

If this does not kill the motor your distributer module is bad

 

[Topvader1]

Awesome explanation! I will try this tonight!

When I am selecting a "good ground" - any recommendations? I could us a wire jumped directly to the negative side of the battery right?

Any idea if I am able to take the distributor module off the distributor without dissembling the entire distributor? How complicated of a job is it to replace that module?

 

[alldodge]

When I am selecting a "good ground" - any recommendations? I could us a wire jumped directly to the negative side of the battery right?

You can go from the battery, but also from the any bolt, nut or bracket which does not have paint on it. You can also scratch the paint off some metal item on the motor and use it.

Any idea if I am able to take the distributor module off the distributor without dissembling the entire distributor? How complicated of a job is it to replace that module?

Removing the module is easy enough, just remove the cap and rotor, then a couple screws and it comes off.

Just remember to let us know what you find before you go and buy parts.

 

[Topvader1]

So I was eager to get this figured out. I followed the trouble shoot above to a t. When I touched the ground directly to the white and green nothing happened. So i pulled the plug out of the distributor module and noticed the wire that goes onto the pin in the module looked damaged and bent back so I thought that might be my issue. I touched my ground wire directly to the second pin in from the left as the far left pin isn't utilized and still nothing.

I found the Sierra part for about $80 for the distributor module. Should I go ahead and buy it?

 

[alldodge]

If your sure the other end of the wire your using to jumper the connections has a good ground, then yes you found your problem. Have you tried to straighten the pin out and try again? If it works with the pin straight, it might just need to be straightened and plugged back in. If not, then you should be correct.

The part number your looking for is 811637001
And if you found this Sierra part number then your correct
http://www.iboats.com/Mercruiser-Ig...6347290--session_id.684371690--view_id.269497

 

[Topvader1]

Yes the other end was to the negative side of the battery. I tested the end of my wire set up with with a meter to the positive and it showed 12+V. I also tested the ground that the shirt interrupt plugs into to the positive side of the battery and it showed 12V. I then Tested the white/green wire from where the interrupt switch plugs in to the end of where that plugs into the module and that showed continuity. So I know my ground and other wire are good when I get the new module.

As far as the module itself - didn't bend or manipulate that pin too much as I didn't think that would make a difference. Do they sell new connectors that plug into the module? Might as well get a new one of those since the pin connector on that wire space looked damaged.

 

[alldodge]

Have been unable to find a pigtail for that connector. Have been looking and I'm sure they are out there but so far I'm coming up empty

 

[Topvader1]

While your looking - is the screw i need for the cap itself part #11976? The current ones are pretty well rusted.

 

[Topvader1]

What do you think about Par #84-817374A01? Says its a timing delco plug - and those two blank white wires hanging out of this plug are used for timing evidently.

 

[alldodge]

What do you think about Par #84-817374A01? Says its a timing delco plug - and those two blank white wires hanging out of this plug are used for timing evidently.

Haven't found a pic but it says its a timing plug, and with that, this should be the correct one

While your looking - is the screw i need for the cap itself part #11976? The current ones are pretty well rusted.

Can not say, here is a link for the parts, and the screws in the cap comes with the cap
http://www.mercruiserparts.com/bam/subassembly/30905/4893/90

 

[Topvader1]

I guess if the two white wires are pigtailed to each other i could just cut them and it would function the same as it is currently.

 

[alldodge]

Yes, but make sure to just cut them apart, don't cut them completely off. They need to be connected together to put the motor in base timing mode in order to set timing if it ever goes out

 

[Topvader1]

Got it - I will be careful just to make one cut in the middle. I found an image of the part number for that plug (it was a foreign website) but it had a picture of the part and a mercury marine tag on it and it looked exactly like whats in there now.

I ordered the module on amazon - it was $80 with free shipping, and I found the screw and plug at Performance Marine out of Florida and that cost $20 with shipping. So $100 and hopefully this is finally solved! I will keep everyone posted on the outcome once the parts get here.

 

[Topvader1]

I was just thinking about the ignition module this mornign - is it common for just one side of the module to be bad? There are two plugs and I am not having any other stalling, starting, or performance issues with the motor or ignition.

 

[alldodge]

I was just thinking about the ignition module this mornign - is it common for just one side of the module to be bad? There are two plugs and I am not having any other stalling, starting, or performance issues with the motor or ignition.

It's not common. One connector controls the spark, the other is for timing and shift process. Someone damaged the pin and caused it not to make contact, hence your issue. From your testing it shows the connection inside the module is broken. If the connection was not broken it would still work.

 

[Topvader1]

Yeah it must be an internal connection in there that's broken. I couldn't find the screws for the cap anywhere so I decided to just replace the Cap while I'm in there. It's a less than $10 part.

 

[Fishermark]

...Check the Whit/Grn wire which goes to the distributor and the other which goes to ground. It could be you lost your ground connection, or the connector going to the distributor is not good

Just to clarify - on the old ignition systems the shift interrupt goes to ground. On the wiring diagram that is posted, the shift interrupt goes to +12v - NOT ground. Adding power to the line going to the distributor should cause it to die - not adding a ground.