Tiny-Tach Question

[Fr3AkAzOiD]

I have a model year 2000 two stroke two cylinder 15 HP Mercury outboard.
Wanted to get a better prop so it was recomended to get a Tiny-Tach so I don't blow my engine.

I now have one and in the initial setup I need to set the number of sparks per revolution.
8 sparks per revolution
6 sparks per revolution
3 sparks per revolution
2 sparks per revolution
1 spark per revolution
1 spark per 2 revolution

I know next to nothing about engines and tried looking it up in the online manual in the sticky with no luck.

If anyone could help me out it would be great.

 

[KRS62]

Re: Tiny-Tach Question

I am certainly not an expert, but always thought a 2 stroke was 1 spark per revolution. Make sure to wait for a knowledgeable person to chime in before you install.

KRS

 

[bktheking]

Re: Tiny-Tach Question

Correct, 1 spark every revolution.

 

[Fr3AkAzOiD]

Re: Tiny-Tach Question

Thanks, I was pretty sure it was 1 per revolution but I wasn't going to risk my motor on that assumption.
Hopefully I'll have enough time to take the boat out on Thursday and get enough info to start shopping for a new prop.
Mine isn't ruined but it has seen better days.
I was looking for an excuse to spend some money anyway.

 

[Fr3AkAzOiD]

Re: Tiny-Tach Question

Argg....

Ok, so I go to the lake today and take a few minutes installing the Tiny-Tach and launch the boat and when I start it up I just get it displaying the max number the screen can display.
I tinker with it over and over again, more twists of the red wire, less twists, grounding it at a different spot, rerouting the cable another way and nothing.

So I just get ticked off and go out on the boat for a while. Downloaded a gps speedometer app for my Droid that lets me take averages.
So I run a one minute run in each direction pausing before turning around. Ends up my top speed for my WaterMouse is only 22 mph.
They are listed as being able to do 24 mph with the 15 hp and I have a compression test done last season and all was good. Guess I may have lost a couple mph from minor prop damage.

So I go back in and start tinkering with the Tiny-Tach again. This time I leave the motor running and find out that with the ground connected and the red wire in my hand it starts registering the engines rpm's when the wire is a good inch away from the spark plug wire. So I start messing with it again. Closer to the spark plug, then farther away, more and less twists, nothing works.
I notice that everything is fine untill I let go of the red wire.
Only thing I can figure is that I am grounding it and when I let go it is not sufficiently grounded and messes up.

Anyone have any ideas?
I do plan on calling their tech support, but not today. I am done dealing with it today.

 

[La Bullet]

Re: Tiny-Tach Question

I just ordered one for my Mercury 90 3 Cly. with an optional extra long cord, I want to mount the display on the dash.

I did notice it says some thing about a filter see Q&A #7
http://www.tinytach.com/tinytach/faq.php

Also check note at the bottom: http://www.tinytach.com/tinytach/gasoline.php

 

[Fr3AkAzOiD]

Re: Tiny-Tach Question

Update

The Tiny-Tach model 2A that I had at first was designed on some lawn mower engine with a really weak spark so when putting on my engine with a strong spark it would overload and error out.

Talked to one of the techs and they sent me out a model 1RXL which supposedly is the updated version of the 1C and has a filter on it. While that one doesn't error out it tells me my neutral idle rpm is 4,600 and my in gear idle rpm is 3,500 which is like four times higher then it should be reading.

Spoke to one of their techs again and he is sending me out this new version they just got in so I'm keeping my fingers crossed.
Should have thought of having them give me an extra long cord but my boat is short enough I'll easily be able to see the reading.

I am frustrated that it is taking so long to get working but the fact that they keep working with me on it says a lot.
I'm keeping my fingers crossed that this one they are sending out will work correctly and I can test it on the water next Monday.

Since I was unsatisfied with my top speed when I took the boat out last I experimented with the angling of the motor when I had it out today.
22.5 mph all the way down and I can take tight turns at near full speed however the bow is a little low in the water with a full tank of gas (5 gallon tank in bow).
23.25 mph on first click, can still take somewhat tight turns at fast speed, bow is a bit higher in water and can run through waves with more confidence.
24 mph on second click, can take medium diameter turns but have to pull off throttle a little in order to prevent prop blow out/ventalation, can take decent sized (compared to my boat) waves without nosing through them.
24.5 - 25 mph on third click, tried once for all of two minutes, blew out prop on a rather wide turn, boat felt unsettled on plane.

Ran the rest of the morning either all the way down playing alongside the wave runners or running back to the docks at 2 clicks to give me that extra 6% top end.