1996 Dt 75 Tach pegs at 7000rpm

[Carl 1012]

I have 3 wire stock tach on the Dt75 .When the ign. Is turned on it pegs at the max 7000 rpm. Can,t find anything much in the manual,wiring diagram etc. Connections look good,tried a good used 2nd tach same result. Is this a common problem? Could the issue be in the ignition switch,the choke was acting up recently,does'nt always activated when key is pressed in.
Any thoughts, come on you electrical sages!

Where is the best place to buy a tilt trim manual release valve for a Showa unit?
Thanks Carl

[Solarman]

dt75, tach problems

Could be a faulty tach control unit # 34250-87D11. If both tachs did the same thing, id look at that. See if your manual shows how to check that. As as the part you're looking for, try to google the part number with the part name. Make sure they show a pic so you know it is the part needed. Can also google the tachometer control unit.
Good luck. You still may need a new switch if choke is not activating when switch is pushed, unless your wiring is not good?
Let us know what you find.

[artdf175]

sounds like your tach is not or has not been adjusted
depending on manufacture there are a couple of ways to adjust

I had a problem 2 years ago with my tach
it started jumping all over and was giving very high readings
was in process of replacing
the mechanic thought at the last minute to move around the slide switch on the back several times.. seems the connection inside was not making good contact.. moving it cleared the problem.. that is how I originally was made aware of this adjustment switch..
if you do a search on the internet "how to adjust a boat tach" there are several good articles on the subject
Art

[Solarman]

dt75, tach problems

That's true Art, there is a switch, I believe it's under the rubber plug. Can turn it a couple times, but put it back where it was originally. Never hurts to try it, but if both tachs did the same, i'm guessing the tach control unit.
Good luck. Let us know.

[artdf175]

maybe should ask Carl a better question
I think the system goes through a warm up when you turn the key on
I don't think it makes any difference where it pegs it at this point - should be just an internal stop point build into the tach..
the question is what happens when you are under operation
is the tach showing the correct idle speed?
when you are operating at WOT.. what is the reading?
If the reading at WOT is 7,000 ,,then I would say you have a problem
art

[Carl 1012]

The tach was reading correctly when last out at one point. It's been a few months seems like it was a little eratic from memory. I can not start or run it currently. I just don't recall it pegging like it does.
I went in search of the tach controller but it does not appear to have one. Parts list says no longer available although it shows one in the schematic next to the CDI unit. I did find a wire yellow with green trace that was disconnected in by the CDI.I'm not sure if it has come loose from a connection.Have looked at the wiring diagram ,things electrical are not my strong suit.When the weather warms up I'll try moving the switch around.
These 96 model Suzies are a rare bird around here. I'd like a blown parts motor but I can only find 80s models and not much seems the same.
Thanks for the replies
Carl

[Carl 1012]

My mistake found the tach controller by the other electronics. Swapped it out with another one ,still acting the same. I,m thinking the ignition switch may have developed a fault. Any more suggests.

Does anyone happen to know if the an 85 model lower unit will swap out for a 1996 model dt75?
Cheers Carl

[Solarman]

Did you try the switch under the plug on the back of the tach?

Look up the part numbers on the gear case and click on that part number. It will tell you all the models the gear case was used on. Then do the same thing on the gears. If the parts were used on the 96 motor it should tell you.

Good luck.

[BillCon]

Carl, check the main "connector" between the motor and the boat, and any place the wire transitions thru a terminal or jumper, and the remote control if your wire cluster goes thru it.