2001 Yamaha 225hp OX66 - Tach Not Working

[spearslinger]

I have a 2001 Yamaha 225HP OX66 with a 2005 powerhead. I just recently had it fixed as it sat up from the previous owner for 2 1/2 years with little to no maintenance. The VST pump was varnished up, YEAH!!! All tanks guts replaced, injectors cleaned and freed up, etc.... Many green backs later, she is running like a champ. My current concern is that the tach is not working. I borrowed a known working tach from a buddy and it gives me the same output, nothing. My tach is getting power as it has an electric hour meter below the tach needle and the hour meter is working. It is currently sitting at 400 rpm's and won't move. I haven't put a meter on it yet, but I ran it the other day and checked the voltage through my fishfinder and it was putting out 13.2 +/- at 3/4 throttle. So I am sure that its not getting over charged. Should the voltage be higher? I am kind of puzzled as to why I have power for the hour clock but not the tach. All of the grounds are wired together in the dash display(MPH, Fuel, Trim and RPM's). The other gauges are working as well as the illumination. The 2005 powerhead only has 13.9 hours on it. It looks brand new. I am sure it's something simple, but it currently evades me. Had a similar problem with my last tach in another boat, but you could smack the front and it would start working. LOL!!! Good ole Southern mechanics. Any "HELP" would be appreciated.

Thanks,
Spearslinger

 

[spearslinger]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Went out in it again, tach still not working.....Motor at idle is producing 13.4V, once in gear, drops to 12.7V but climbs back up with throttle. Tried swapping tachs around again and nothing changed. Any pointers would be appreciated.

 

[rodbolt]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

what brand of tach?
the tach send on the yamaha 10 pin main harness is dark green.
key on power is yellow and black is ground.
at key on,if the tach is actually powering up, the needle should reset to zero.
the tach signal on that engine is generated by the ECU not the altenator so charging system wont affect the tach signal.

 

[spearslinger]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Not sure of the brand of tach. The gauge cluster is a Travis Edition series. It's white with a digital hour meter. I have black - ground, two wires purple and blue on 12V post. Green is signal wire. And then another blue for illumination. Tach is not reseting to zero. So I guess my first step is to find out if I have 12v at the post? I should if the hour meter is working right? I put in a spare known working tach and same thing. The spare is all analog. It won't reset to zero either. What should my poles be set to? I think its on 12 now.

 

[spearslinger]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Bump

 

[rodbolt]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

12 pole is correct
sounds like an aftermarket non yamaha harness.
trace the purple wires back to the keyswitch and make sure they are connected.
test between the purple and black for 12V.
with water supplied to the engine check for a varying voltage between the green and the black.

 

[21Contender250]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Where excatly does the green signal wire go to on the motor?

 

[rodbolt]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

dark green in the 10 pin is generated by the ECU, therefore thats where it goes.
unlike some other brands this engines tach signal IS NOT related to the charging system.

 

[spearslinger]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Rodbolt,

Alright, seems I found the problem or I have it working for now, LOL!!! The test tach I used before must not have been getting the proper signal or I jiggled the wires in the right order. Jumpered the test tach to my existing tach and the test tach reset to zero and then showed RPM's once engine started, existing tach didn't move. From ground to Signal, I was getting a reading of variances, hovered mainly around 6.6, but would dip as low as 5.4 and high as 7.1 depending on engine hiccups.....this was done on a cold engine. Swapped tach's and everything is still working fine. One thing that was pointed out to me was that my key switch doesn't buzz or alarm when I turn the key to start the motor. I pulled the kill switch rope, engine off, and it does alarm when that is activated so the alarm horn itself works. Not sure as you stated earlier that this harness might not be a Yamaha harness. I do have the 704 binnacle and a Yamaha key switch. Gauges are Faria though and there is a tag on the harness that says Marine Electronics etc....... Looks like a parts tag. Please let me know if all this sounds about right. Thanks.

 

[rodbolt]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

sounds like the elcheepo rigging a lot of manufactures used.
thats why it gets flackey sometimes.
that engine,as a single, does not self test the alarm at key on.

 

[spearslinger]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Rodbolt,

Did those voltages sound right to you? Just curious....

Thanks

 

[spearslinger]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Got out for a run in the boat yesterday since trading out tachs..... I was getting 4500 WOT with a full fuel load of 80 gallons, 3 people, 2 sets of dive gear, 4 tanks and was clipping along at 48mph according to GPS, 51 according to pitot valve on motor foot. I thank that's good, but wondering if the tach is now wrong or the prop isn't right. Gets a good jump up, engine doesn't seemed overloaded. It is a 2300 series Fishmaster bay boat with an 225 Yamaha OX 66. In my opinion that speed is great with that load. Just worried that I'm not operating at the proper RPM, have another faulty tach, or wrong prop. Is there another way to check RPMs with a meter while underway? I hate to keep going through Tachs, LOL!!!

Thanks.....

 

[rodbolt]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

only way to check your tach is with a known good inductive tach and compare the two. 4500 and that motor is lugging hard and will be short lived.

 

[spearslinger]

Re: 2001 Yamaha 225hp OX66 - Tach Not Working

Changed props out. Swapped a 23 pitch for a 19 pitch. Rpms now in the 5400 range. Lost 5 mph top end, but the boat will now pick the first 12 feet completely out the water, LOL!!! No problems planing off or anything, seems to be fine......any other suggestions? I think the pitch was the RPM problem.