Yamaha multifunction Tach problems

[skpcoastal]

I have searched and read the previous threads still clueless. I have a Yamaha multifunction tach that reads 0 at all times. New boat to me. Rebuilt the LCD. 1995 vx250 Carb the year before the ox66 fi. Just bought some used gauges 2 tacs seller said both worked but faint. Both of those show also 0 (RPM). Thought it was a bad Tach now I am pretty sure that all three gauges read the same that's not it. Disconnected the three green wire harness from coils or stator. Shows AC volt to ground on all three green wires. Hz too. Both increases with RPM. All three green wires to gauge reads 0 on gauge. So where can I pull a good Tach signal on motor? So what next?
just want to figure out how to troubleshoot.
Local shop who I have used before just said bring it in and would not discuss it. unfortunately that's difficult.

Is the CDI bad? The engine runs fine. can I bypass that for the tach previous post seemed to say that was possible but I must have not been using the right wires.
going to buy the shop manual but don't know that will help
thanks for the help

[rodbolt17]

why test the lighting coil?
the tach signal is generated by the ECU based on a pulser coil signal.

[boscoe99]

And by the way, the stator output is not measured to ground. It is measured green lead to green lead.

[skpcoastal]

ECU? this is a carbureted 1995 250. ok how do I test the Pulsar?

here is one of the threads I was looking at

http://www.yamahaoutboardparts.com/f...o-th26653.html

Can any one follow what he did in this thread?

http://www.yamahaoutboardparts.com/f...h-th11789.html

[boscoe99]

ECU? this is a carbureted 1995 250. ok how do I test the Pulsar?

here is one of the threads I was looking at

http://www.yamahaoutboardparts.com/f...o-th26653.html

Can any one follow what he did in this thread?

http://www.yamahaoutboardparts.com/f...h-th11789.html

ECU/CDI are used interchangeably to denote the brains of the motor. Some may call it a power pack, an ECM or EMM.

[throrope]

Same reading with multiple tachs may indicate the most often cause, which is a bad wiring connection.

I suggest cleaning all connections and checking continuity engine to gauges, engine to ground, gauges to ground and ground to battery since many harnesses have a dedicated console to ground. If you find a problem, it will be the cheapest to fix no matter how many components you replace before you found it.

[rodbolt17]

Yamaha never made a Vx250 in 95.
however even the old carbed 250 in 95 used an ECU. sometimes called a microprocessor.
it also used six carbs with enrichment solinoids a TPS a knock detect and an engine temp sensor.

VX250 was made from 02-04 did not use CCS and was an EFI.
this is why model numbers are rather important.

the VZ250 was made from 02 -05 about all it shared with any other EFI or carbed Yamaha was a paint code.


if I needed a set of carb kits for a 1995 225 what part number would I need ?????