Tiny Tach problem with rotax 503?

[GrantR]

My Tiny Tach is reading erratic rpm readings. It worked fine at 1st then started this crap. At around 2000 rpms it shows 4 or 5k and 7K at WOT.

I can squeeze the tach wire tight to the spark plug wire and get an accurate reading sometimes.

I tired resetting the tach, wrapping more wire around the plug wire and less wire. Nothing seems to work.

I think its still under warranty.

Any Ideas?

[Chuck Roberg]

Don't know the answer. But you can give them a call.

http://www.tinytach.com/tinytach/faq.php

[Oskar]

Have you checked the ground wire? It needs to go somewhere onto the engine block.

[getut]

I had to do the tiny tach dance with my soob.

Make sure both TT wires are routed as far away from any other plug wire or the mag as possible. Make sure the tach is grounded well and make sure the engine is grounded well.

Also keep it away from the AC wire going to the regulator/rectifier. Straight up DC wiring doesn't have an effect on it.

[GrantR]

Well I called Tiny Tach and found out that the model I have Model 2C is not the right one for the ducati ignition! Works for the old points one but not for the newer ones!

That explains a lot so I am getting the correct one which is the Model TT2S which is programmable. The newer ducati fires ever 180 where the points doesn't.

[Dirtydog]

Grant R:
Hey I would have sent you my old one since I installed a reg. RPM / hour meter tach. I think my TT started having problems but it was a free bee 2 U if U wanted it....

[jamestarantyler]

I'm having the same trouble I have old rotax 503 with points I have the 2c modle an called tiny tach an they said it should work. It idle it reads around 1500 then half throttle its already reading 6 then at wot its jumping around. Any Ideas were my problem May be Grounding?? I wraped the red wire around plug wire then wraped it in electical tape. Thanks guys for any imput.

[Dirtydog]

jamestarantyler :

It is junk buy a new one...Mine did the same thing....I bought a RPM G for my pod this time.

[Redbaron]

throw that china crap in the trash! you got the right prop for your engine? only guages I trust are my airspeed and butt meter aka g- force! match the prop to the engine! grant the 503 is probally the most used and reliable engine in the ultralight world!