Shift Interrupt Switch

Cricket Too

Lieutenant Commander
Joined
May 14, 2003
Messages
1,732
Hey guys, I had a problem with my shift interrupt switch a month or so ago on my 2000 Johnson 200. It would cut out 3 cylinders like it's supposed to when shifting, but it would keep them cut out in reverse, and I'd stall every time I docked, or have almost no power.

I disconnected it, but haven't gotten around to replacing it yet, and have been using the boat pretty regularly, since it's striped bass season. Just wondering if this could possible cause any damage to the lower unit? I am careful with it, I always let sit in neutral for a couple of seconds before going into reverse, and never shift it quickly between forward and reverse.

Just wondering if I should pull the boat and replace it, or if it's something that can wait until the bass run is over and I can do before I winterize it.

Thanks.
 
D

DJ

Guest
Re: Shift Interrupt Switch

and never shift it quickly between forward and reverse.

Exactly the wrong thing to do.

Shifting it slowly allows the clutch dog ears to grind and round down.

Shift it quickly.
 

Cricket Too

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Messages
1,732
Re: Shift Interrupt Switch

DWJ, maybe I should have phrased that differently. I didn't mean that I shift into gear slowly, I can't stand the sound of that even when other people do it to their motors. I always shift quick and hard into gear.

What I meant was that I don't shift quickly between forward and reverse, as to aleviate some pressure on the lower unit, since the swicth is gone. When going from reverse to forward or vice versa, I let it sit in neutral for a second before going into the other gear.
 

R.Johnson

Rear Admiral
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Sep 24, 2003
Messages
4,446
Re: Shift Interrupt Switch

Check the switch with a ohm meter, or continuity light, or check the adjustment, again a service manual.
 

Cricket Too

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Messages
1,732
Re: Shift Interrupt Switch

I guess maybe there could be something wrong with an adjustment. But the switch got pretty soaked in saltwater and then sat, so I figured it was just sticking, disconnected it and my problem is gone....engine runs perfect.

I just need to know if running it temporarily like this (without the switch) will hurt anything. Probably gonna have it in the water for another month and a half and will use it every weekend.

Just don't want to hurt the lower unit.

Thanks.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Shift Interrupt Switch

Running without it won't hurt a thing. It's probably only out of adjustment anyway. Since it does keep the 3 cylinders shut down we know it's working. But we need to understand how it's supposed to work.

It shouldn't have any effect on the ignition when going into gear. Only shifting out of gear into neutral.

Because of the severe backcut on the engagement lugs on the dog and gears, if the motor idles too high you'll never get it out of gear without the interrupter. Well, not easily anyway. If you can shift out of gear easily, you really don't need it. That switch was missing on my 60* 150 when I bought it 5 years ago. I have no intention of getting one. I don't need it. My 150 idles at about 550 or so in gear and comes out of gear as smooth as glass.
 

imported_lorin

Petty Officer 2nd Class
Joined
Jun 23, 2006
Messages
199
Re: Shift Interrupt Switch

It's been a while since a replaced one, but I don't recall there being any adjustment available on the shift assist switch. Or is my memory failing? If so, where's the adjustment? Also, although it's easier, it's certainly not necessary to pull the boat out of the water to replace the switch.
 

Cricket Too

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Re: Shift Interrupt Switch

Dhadley...Thanks, it's good to know I won't be hurting anything. It's also good to know that the switch isn't really all that neccesary. My engine's run at about 600 or 650 in gear, so I guess I'm safe.

As far as adjustment, I wasn't aware that there was an adjustment on it either, but I'm assuming Dhadley is talking about an adjustment to the linkage rather than on the actual switch. Dhadley any info on how to go about checking for adjustment?

I did think it was supposed to cut the 3 cylinders out when going from neutral into gear, but you say it cuts the 3 cyl out when going from gear into neutral.

That makes more sense to me actually, and I can understand now why I had a problem when I came from forward into neutral. The engine would idle at about 350-400 RPM going from forward to neutral, and would sometimes stall, and I would have to shake the throttle lever in order to get it to idle normally, so I guess what was happening was that it was cutting 3 cylinders out when I would go from forward to neutral, and the keep them cut out when I went into reverse, rather than turning them back on. So I was assuming it was reverse when actually the problem was when I went into neutral. Either way disconnecting the switch solved it.

The reason I figured the switch went bad was because at the end of last season, this boat sunk slightly and the engine was submerged to about halfway up the cover, and the switch was definitely submerged as it's sitting in the bottom of the pan. I took the appropriate measures and the engine is fine, but I never did anything to that switch, so when it started to act up, I figured it had gotten dunked in saltwater, and after sitting over the winter the switch was done, because as soon as I put it back in the water in the Spring it had this problem, I just kind of lived with it for a little while before it occured to me that it could be the switch.

Anyway if there is an adjustment to check, please let me know.

Thanks, Mike.
 

imported_lorin

Petty Officer 2nd Class
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Jun 23, 2006
Messages
199
Re: Shift Interrupt Switch

It makes sense that, as Dhadley says, the function of the switch is more important when going from forward or reverse into neutral rather than vice versa, but the switch also does cut out the cylinders when going from neutral into either gear. It is operated mechanically (by something like a cam if I recall). The switch runs over the cam whenever shifting takes place, so it is activated when going from gear intto neutral or from neutral into gear.
 

Cricket Too

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Messages
1,732
Re: Shift Interrupt Switch

Yeah makes sense to me. I have actually looked down at the linkage and seen how it operates the switch. I may try plugging the switch back in and try pressing it manually while sitting in neutral, just to see if it works properly when I push it and let off, at least that way I'll be able to tell if it's the switch or if there is something on the linkage out of adjustment.

It slips so easily in and out of gear that I kind of doubt there is a linkage adjustment problem, but I'll look at it.

At this point though the bigger problem to me is the lean sneeze it has developed at idle. Only started this last weekend, but does it consistently at idle. I gotta check my fuel lines for any air leaks before I go any further. Can't deal with smoking my engine.

Thanks.
 

Cricket Too

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1,732
Re: Shift Interrupt Switch

So any info on how I would go about making and adjustment or check for out of adjustment? Is it the switch itself that get adjusted or the linkage that controls the switch?
 

imported_lorin

Petty Officer 2nd Class
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Jun 23, 2006
Messages
199
Re: Shift Interrupt Switch

Of course the shift linkage can be adjusted, but if there's any adjustment of the shift switch itself I'd appreciate learning about it too. I looked at a later model motor recently and didn't find any. Don't remember ever seeing any on earlier models either.
 

Cricket Too

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Joined
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Messages
1,732
Re: Shift Interrupt Switch

Yeah I took a look at mine, it's a 2000 200HP Johnson, and I didn't see anything resembling an adjustment on the switch.

I'd really rather not spend the $50 on a new one, so I'm either gonna leave it off or try and adjust it, if there is a way to.
 

Cricket Too

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Messages
1,732
Re: Shift Interrupt Switch

Well I manually pushed the switch while in Neutral and it cut 3 cylinders and then they came back as soon as I released it. So the switch is working correctly. But when I hook it back up and go from Forward into Neutral, it cuts out the 3, but they don't come back and I either stall or idle at about 400 RPM in Neutral. When I try to shift from Neutral into Reverse it keeps the 3 cylinders cut out, and either stalls or has no power....making docking no fun.

Is there any way to adjust this switch?? Or adjust anything at all that could be causing this??

Thanks.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Shift Interrupt Switch

It's been a long time since I had to adjust one but if I remember right you adjust the shift linkage. At any rate the manual will outline the proceedure. You could disconnect the cable and shift it by hand just to see if it works that way. When it's correct the shift lever on the powerhead will be straight up and down without the cable connected.
 

Seasport

Chief Petty Officer
Joined
May 2, 2005
Messages
410
Re: Shift Interrupt Switch

Hey Cricket.
Are you sure the switch itself isn't sticking in once the shift mechanism activates it? From memory it's a spring loaded microswitch. It may have got a bit of water into it and corroded as you say. Can you spray some CRC or WD40 into it.
 

#1CATDADDY

Cadet
Joined
Apr 23, 2007
Messages
23
Re: Shift Interrupt Switch

Could that also affect the shifter to not allow it go into neutral? (stuck in gear until you turn the key off)
 

fishtrap

Cadet
Joined
May 24, 2010
Messages
8
Re: Shift Interrupt Switch

has anybody heard of a shift switch cutting all spark causing a no start on a 96 150 johnson faststrike...this condition only happens after a long run and then set for 1hr or so and then will not start--no spark....after it cools down it will fire.....last night after cranking for probably too long i shifted into gear forward and reverse a few times and it fired which made me take a look at the shift switch which has a black/yellow stop wire coming from it..it tried to unplug this same wire when it would not start & no change...this has been a problem all year every now & then but its getting worse...the only constant is after a long run at high rpm which leads me to beleive its a heat issue but no warning lights...the extended cranking last night may have moved enough cold water through that it actually cooled it down enough to start if thats the case what could the problem be the power pack??????????
 

thehermit

Petty Officer 1st Class
Joined
Aug 21, 2002
Messages
305
Re: Shift Interrupt Switch

Good Thread. Has anyone got a picture or a diagram/book page of one correctly adjusted?

I recently rebuilt my 225 looper and the switch does not seem to work correctly. Like others...if I depress it works...like others it sometimes kills 3 cyls when coming off plane and stalls engine. I didnt realize it was "non esential"

Hermit
 
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