Missing, tach all over the place????????????

[Lvnspeed]

I have been fighting a bad miss in my boat ( 2000 GT 40). Well after 6 months at the dealer the mechanic told me that the tach is bad and it is causing the motor to miss fire. Can this be right? I wouldnt think a tach would cuase a boat to misfire but just the opposite the missing boat would cause the tach to be allover the place right?

[DanielC]

The tach wire just pushes on a terminal on the back of the tach, I think it is a gray wire. Unplug the wire, and see if the miss goes away.

[JUST-IN-TIME]

yes a bad tach can cause motor problems
see it all the time on mercruisers

[Lvnspeed]

The tach wire just pushes on a terminal on the back of the tach, I think it is a gray wire. Unplug the wire, and see if the miss goes away.

I asked that to the mechanic this very same thing he said it would run with out it can this also be right?

[Lvnspeed]

yes a bad tach can cause motor problems
see it all the time on mercruisers

WOW I would have never thought it. Thanks for the help.

[JUST-IN-TIME]

the tach gets the reading from the negative side of the coil
so what a bad tach does is ground out the coil, making it not fire
i think on your model it is a big plug, you will have to cut the grey wire down a little ways so you can tap back into it

[DanielC]

My bad, i posted what the tach wire on my 1997 was. You have a 2000, probably with the teleflex gauges.

[Lvnspeed]

the tach gets the reading from the negative side of the coil
so what a bad tach does is ground out the coil, making it not fire
i think on your model it is a big plug, you will have to cut the grey wire down a little ways so you can tap back into it

Thanks I will wait and see what the mrina comes back with i have given them until Wednesday to fix the problem or I am going to pick my boat op on friday.

[Lvnspeed]

Well the marina said the distributer needs to be rebuilt but they dont have a way to press it apart. is there any instructions on rebuilding a distrubtor on here or can anyone guide me?

[Lvnspeed]

picked up the dist. it looks like the plastic pickup under the silver slotted disc is loose and rubbing on the silver slotted disc I am going to take it apart but Where do I buy parts?

[DanielC]

Go to a Ford dealership. Ford used the 351 engine in mid 1990's full sized pickups.