Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Hi all,

I need to adjust the RPM of my Tecumseh L-Head (9 HP / 318 cc) engine that I bought in 2007.

For that purpose, I plan to purchase "digital photo (laser) tachometer".

From my understanding this tool works by sticking a piece of reflective tape on a rotating part of the engine (such at the shaft near the pulley where the belts are located). The tool then counts the number of time this piece of tape passes in front of the laser beam in one second and multiplies by 60 to display the RPM.

Did anyone ever used such a tachometer? If yes how are you satisfied with this tool?

Also, I need to know the RPM values that this engine should be adjusted to at: full throttle and also when idling. Do anyone know these RPM values.

I see what you mean Dave i will have to play with those pictures and see if i can get them smaller.I noticed the battery in my tach is glued in.It looks like i could get it out though.For cheap tachs even with slower refresh rate i found measureing sag was ok.I tryed to pick areas were i went at least 10ft and mostly longer.I did have to use a small flash light as most was done after dark.Than i noted my average was between 3050 and 3300 sag rpm from 3600