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1992 25 mercury still cutting out

A

arkansashunter

Member
Hey. I have a 1992 mercury 25 that i just put a new switchbox on. It has mechanical timing advance.

It starts up and idles great but when i increase the throttle it dies. At first i thought cdi may have sent me the wrong switchbox but i swapped it for a mallory and it does the same thing.

The odd thing is when i removed the throttle advance linkage under the flywheel it reves just fine. What would be causing this? Before it ran just fine.

There is a picture attacted showing exactly which linkage it is.

I added a charging coil to the motor, Could that be causing this?

Thanks
 

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Could this be cause due to a bad trigger? on the multimeter with the throttle at idle it reads 7.8 then when you throttle it up the reading completely drops out of range. Is this normal? this directly relats to when i disconnect the linkage and the trigger remains in the same spot the motor doesnt kill out. Does this make sense?
 
.."I have a 1992 mercury 25 that i just put a new switchbox on. It has mechanical timing advance."

I thought that motor came with the electronic spark advance? It sounds like you have a combination of the two types somehow. Out of ignorance, I did it the other way around once (mechanical advance motor with an electronic spark box) and had the opposite problem: it reved up alright--and wouldn't stop!

Jeff
 
it is for sure mechanical advance, thats why im really baffled by this. I guess it could be a stator issue. but i dont understand why disconnecting the trigger linkage would suddenly fix it.

I am strongly considering just putting all the mechanical advance hardware on it from my non running motor and being totally done with it,.... hopefully that is
 
problem solved!! It was a bad trigger. Had to pay the 10 bucks to the mercury hotline but they narrowed it down for me. Well worth it to be done with the headache lol. Now just gotta get the tiller handle tightened up some but good to go.
 
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