Mercruiser Early Style Interrupter Switch

[aspen31]

Hi all
Attempting to troubleshoot a 1978 Crestliner 2455 / Mercruiser 228 with a harsh to nearly impossible shifting problem. Found the brown wire broken at the interrupter switch. Re-soldered and reinstalled only to find that the engine will now only turn over but not start. If I disconnect at least the brown wire from the terminal block associated with this switch the motor will once again start. I even installed a spare new switch but same result. The plate which activates this switch looks to be installed and adjusted correctly - the small push button is nearly centered in the bottom of the "U" in this plate. The wiring looks okay - I can trace the brown wire from the small terminal block to the negative side of the coil and I have established continuity through this wire at least from the coil to the switch.
Any help or suggestions greatly appreciated.
Warren

 

[Bondo]

Re: Mercruiser Early Style Interrupter Switch

Attempting to troubleshoot a 1978 Crestliner 2455 / Mercruiser 228 with a harsh to nearly impossible shifting problem.

Ayuh,.... Why don't you Explain the Problem, rather than your attemps at Fixin' it....

 

[aspen31]

Re: Mercruiser Early Style Interrupter Switch

Sorry
The motor initially ran but wouldn't come out of forward or reverse or would do so with great effort. I read your forums about the interrupter switch and upon inspection found that indeed a wire was broken on mine. I resoldered and reinstalled it now to find that the engine would turn over but not start. if I remove the brown wire from the small terminal block associated with the switch the engine once again will start. I tried another switch but same results - crank but not start.
Thanks
Warren

 

[lowkee]

Re: Mercruiser Early Style Interrupter Switch

Try removing the switch from its mount and trying to start it. It may be bent in such a way as to not switch off. If you own a multimeter, test if the switch works or not while it is disconnected from the engine (continuity test). Also make sure the wheel of the switch is centered in the shift plate's dented portion.

 

[totx]

Re: Mercruiser Early Style Interrupter Switch

if I remove the brown wire from the small terminal block associated with the switch the engine once again will start. I tried another switch but same results - crank but not start.
Thanks
Warren

The switch is NO (normally open) making contact when engaged.

Sound like you have 2 bad switches ore a short in the termination block.
(Ore short in the wires from termination block to the switch)

Don't know what your termination block look like,
but if it have 2 screws, one long and one short.
And the long one is attaching it to the engine.
The long one have to be with the black wires, if not you are grounding the brown wires from the coil....

 

[aspen31]

Re: Mercruiser Early Style Interrupter Switch

Hi again all
Thanks for the help and suggestions so far.
Totx, you were exactly correct. Some genious had hooked the interrupter switch wires reversed on the small terminal block. I switched them and "off she went". The interrupter switch is being a bit cantankerous going from reverse to neutral but I think this is an adjustment -- at least we can get out in the old girl.
Thanks
Warren

 

[totx]

Re: Mercruiser Early Style Interrupter Switch

Sorry
The motor initially ran but wouldn't come out of forward or reverse or would do so with great effort.
Warren

Don't know what your shift plate look like.

Sounds like it's "killing" to late. (ore was not killing at all)

If you have the switch type with an arm and roller.

Move the shift plate by hand in idle, the switch should kill when the
roller is approx 3 mm (1/8") out of the grove.

 

[Bt Doctur]

Re: Mercruiser Early Style Interrupter Switch

The switch is operating because of corrosion in the shift mech, or from a damaged shift cable.

 

[Bondo]

Re: Mercruiser Early Style Interrupter Switch

The interrupter switch is being a bit cantankerous going from reverse to neutral but I think this is an adjustment --

Ayuh,... I'm guessing it's because you need a New Shift Cable....

 

[SSTKO81]

Re: Mercruiser Early Style Interrupter Switch

Would this switch completely cut off ignition or just "dampen" it. I'm getting spark to only one cylinder and trying to trace it back. -unlikely cause the more I think about it, but it's worth a shot in the dark I suppose.
Are there any detailed diagrams of this switch and proper wiring?

 

[Bt Doctur]

Re: Mercruiser Early Style Interrupter Switch

Check your messages

 

[Don S]

Re: Mercruiser Early Style Interrupter Switch

You really need to start a new thread with your questions. Otherwise your post will soon be invisable.

 

[SSTKO81]

Re: Mercruiser Early Style Interrupter Switch

Big time help Bt. Thanks. Don't think the switch is really my problem, cause it was working fine last season when I put it up. But at least I know for future reference.
And sorry about the "old" post Don, just tryin' to keep the place from getting jumbled up with a million new threads.