Tiny tach vs. Sendec.

The newer adjustable tiny tach will work just fine if it is set up right. It's user error, how do I know, cause I was in the same boat. Make sure it's grounded, and wrap it starting at the filter, not the end of the wire. Start with 2 wraps, it will read something, if it seems way off try another wrap. make sure it's not in contact with the other spark plug wires.
It's a great product once it's set up right.

 

If it's not getting a reading at all it means you have a bad ground connection. Make sure it's bolted to the engine block tightly.
If it was just not hooked up right it would still read but be way off.

 

I have a question -

So if it reads something and then wrap it again and it reads something else and maybe another wrap you get another reading, how do you know that it is not guessing-or making up a number ie: how can it be trusted?

Just asking because I do not understand all of the confusion around a this particular tach. I just keep reading about people buying them and calling the nice people to get another and many times that one doesn't work either. Not trying to bash anyone just trying to understand how this can be trusted to produce an accurate and reliable reading.

 

It's easy, you adjust it until it reads correctly, you will know when it's right when it matches your idle. IE the idle on my yamaha is 1000rpm +/- 50rpm. If it's not wrapped right it will jump all over the place and read way off. Mine read 2500rpm when I was wrapping it from the end instead of the base.

The old tiny tachs were the ones everyone had issues with, not the newer ones. The old ones were motor specific and never intended for outboard motors. They were really meant for generators, and pump motors.....
The new tiny tachs are made to work with outboards and you can actually adjust them (ie 2cyl, 3cyl, 2 stroke, 4 stroke). It comes with a chart to select your motor and pretty foolproof. The only reason you should have to send it back is if you need longer leads, or if it's broken which is unlikely since it's a very tough little unit.

 

This is not correct an Ducknut has a valid argument here.  Just because you can match idle rpm does not mean it reads correctly at higher rpms.  Been through this too many times.  Unless you tach your motor at idle with a tach that's certified to confirm it's idling at the recommended idle level, you are assuming it's correct but in reality it could easily be off 50 to 100 rpm at idle.  I used multiple tachs and if 3 matched I was reasonably confident my rpms were within a safe margin of error.

This is correct and what I recommend to my customers

 

Thank you Skiff Shop as that was going to be my next question.

So if the idle is actually 900 and you think it is suppose to be 1,000 because that is what the manual says and you calibrate it to 1,000 then at w.o.t. you really could be off by several hundred rpm's.

Ron, is there a plug in tach for these little motors like there is for the bigger ones?

 

Actually I did tach mine with a certified tach, thanks to a friend at toyota. And the tiny tach was fairly close at all times to the protach once it was set up right (yes it was way off when I set it up incorrectly by wrapping from the end instead of the base), never off by more then 20-30rpms throughout the throttle range and most of it was due to the lagtime compaired to the protach. A tiny tach does not work like a traditional tach, there are no mechanisms to an analog guage. It's a purely digital read out.
The only real way it can read exponentially off at higher rpm's is if it's set in the wrong mode (ie 360 instead of 720), or if it is set up incorrectly (too close to another sparkplug wire...). In either scenario it won't read a few hundred rpm's off it will read a few thousand and be very obvious. (ie, my first tiny tach which was an old model, would read only 3000rpm's at full throttle because it was the wrong one for my motor)
The older models were a nightmare because they were never intended for our application and had issues dealing with the interference our outboards put out. Thats been solved with the new models and additional noise filters. Will it ever be as accurate as a traditional tach, no, but it will be close enough, and really who the hell needs to be that close on a non race motor? all you need to do is get a ball park so you can prop it right and then use it to count your hours.

 

I use a digital laser shop tach to set my idle speeds.
It's an inexpensive tool that requires no wires.
A small piece of reflective tape on the flywheel
is all that's needed for an accurate rpm measurement.
On the water I don't worry about rpm's when fishing.
Only when testing props or adjusting throttle settings.

 

Unfortunately, not that I'm aware of but you can wire one up if you have an electrical/charging system.  If I remember Yami plugs into a green wire.

As Brett stated, it's only important in initial propping and I've propped so many now it's normally comes down to two potential props based on weight.  The addition or removal of gear and/or persons has a bigger impact than the prop at this point.  If you pile a bunch of gear and people on the boat and it won't jump up, you know you need to drop pitch.

For most on this board it seems like a crap shoot on the tach unless you have FC's resources to verify the tach.  While it was stated that the rpm cannot change exponentially it's pretty tough to convince me to have confidence in a product that you have to "fiddle" with to get numbers we want to see.  I used to buy two models of the tach ten at a time and lost my tail in the cost of shipping replacements. I have several that "seem" to read correctly at idle but not at high rpm's. When it's removed and careful attention to detail to instal the replacement exactly the same as the last can only make one wonder when the new one functions correctly. I had a whole ritual I used to go through with Merc 25 2 smokes so I was consistent for this reason. :

I have had great results with the upgraded model and I simply reuse it when propping a customers boat. Then remove it when we are done.

 

Doubt it, should work unless it is defective, what did tiny tach tell you when you told them the code it's relaying? I know you said you have a solid ground, but can I ask where and how you are doing it? i had an issue at one point where I grounded it with a bolt on a bracket off the block that I thought was steel but turned out to be aluminum and wasn't giving me a good ground so the unit would flicker.

 

I am having the same "no reading" experience as SaltySouth with a TT2AK, with the filter, on both of my outboard motors. I have a Mercury 15hp 4 -stroke 2 cylinders and a Nissan 8hp 4-stroke 2 cylinders. The display never changes from the Total Time display no matter how I wrap the red lead, and no matter what I attach the white lead to. I called and Steve, at Design Technologies, asked me to try making the red lead longer. I tried wrapping the 1.5 foot lead around each of my spark wires. Same result, so now they are sending one without a filter for me to try.

 

Do like all of the others do and call Tiny Tac and tell them the problem and they will sell you the right item. It is mindboggling how many people buy one of their tac's only to be kicked in the head because they don't work on their engine.

Think about this- if you nuy one of these things that by all indications says it will work and then it doesn't and you fumble around trying to fis the issue and finally get it to work - how do you trust it is providing you with correct information?

 

I installed a tiny tach on my 25 2stk yamaha. It took 10 min and works great.

 

Mine dosn't work worth a --it can't figure out a 3cyl 4s.
i know i'm proped right so i only use it for keeping track of my hrs for oil changes. :-/