tachometers?

Boog · Aug 30, 2005

I got to wondering why manufacturesr don't put tachs on lawn/garden tractors? I see there are a couple companies making small digital tachs that look like (and actually "are" also) hour meters. Does anybody have one of these little tachs? How do you like it? What is the average RPM of lawn/garden tractor engines when full throttle? I have a generator that runs at 3600rpm - is that what tractors run at also? Is it possible to over-rev small engines? I never see anything like this on discussion forums or even in owners manuals on machines with small engines. Thanks folks, J.

hobbyfarm · Aug 30, 2005

( I have a generator that runs at 3600rpm - is that what tractors run at also? )

Generators usually need to run at some multiple of 60 to get the frequency right (at least our US frequency) (unless it is electronically frequency controlled) 1800 rpm and 3600 rpm are very common for generators. It also depends on how many poles the generator unit has as to the rpm the engine runs.
Lawn tractors it usually doesn't matter (about the tach) since you run them wide open for maximum blade tip speed.

Clear as mud? /forums/images/graemlins/frown.gif

Charlie_in_TX · Aug 30, 2005

I was told they don't put tachs on because the motors should always be used at full speed. They will not overspeed but they will overheat if underspeeded.

I bet the tachs you see are for the lawn mower racing community.

orangebluegreen · Sep 3, 2005

I’ve also been looking for a tach. Think I’ve seen the tachs you’re talking about at Northern Tool. I had hoped they would become cheaper like all other electronic products but the price now is over $40. a bit steep if you ask me. If you know of one less expensive please let me know. My Kohler garden tractor is supposed to run at 3600 rpm and with age it doesn’t sound like it is quite running as fast as it used to. I would like to increase rpm so I get as much ground and tip speed as possible without over revving the engine. I don’t want to do it by ear however because my ear always wants more. YES you can blow up small engines by over revving, trust me on this one. Many years ago (decades actually) I put rods through bocks on smaller engines (not Kohler), don’t know where that limit might be on a Kohler though.

ccbob · Sep 8, 2005

Hi, I purchased a tach/hourmeter from a company called SenDec meters. They can be found at sendec.com. Mine works great and I used it to check both the idle and high speed settings. Nice gadget to have. The model I bought #805-100-222 was $53.21 with shipping. Check out their site. /forums/images/graemlins/grin.gif Also, you can soldier on a small battery charger type alligator clip to the pickup wire to make a nice simple way to attach over the plug wire. (one plug wire does it)

1962 · Sep 11, 2005

i put hour meters on all the engine powered toys. if i bought it new or rebuilt the engine it has one. sendec brand self powered tach/hour meters work real nice. tiny tach brand hour/tach meters for the diesel engines that the transducer attaches to the injection line. and a few quartz 12 volt mechanical hour meters.
they are nice to have if you use a machine alot. keeps a reminder of preventitive maintenance. oil changes, air filter, spark plug, and many other checks. alot easier than guessing when you last addressed something.

DmansPadge · Sep 11, 2005

Like 1962 said, I put a hr. meter on all my engines if they don't come with one. I also bought a Sendec meter. It cost $27.99 at my local Sears. I think an hour meter is a good investment but I don't see the need in a tach on a lawn tractor. Like mentioned in another post.. they are meant to be ran at full speed and I can't see it overspeeding unless it through a drive belt or something similar. Even if that would do it... you shouldn't hurt anything by the time you react to idle it down or shut it off.

California · Sep 11, 2005

I have an inexpensive tach device made by Briggs & Stratton that I use occasionally to verify the governor maximum is set correctly. It is a wheel with a wand that you extend little by little, until it vibrates in synch with the engine.

I think it is sufficient to verify the governor setting occasionally, as part of routine maintenance. Since there is a governor there is no need to monitor rpm continually on this type of engine.

Boog · Sep 16, 2005

I got a Sendec tach. I installed it and find that WFO on my GT235 is about 3300rpm. I was surprised to find that the idle was set at about 1620 when it should be more like 1000. I'm glad I got this little puppy - now I can reduce my idle to where it should be. So far I like this little tach. For those who do not run WFO all the time these things might be handy to have. Peace all.

CarlGlas · Jan 10, 2006

( I got to wondering why manufacturesr don't put tachs on lawn/garden tractors? )

In 2003 I purchased a Sears DGT 6000 (27 hp Kohler Pro) and it came with a tachometer. Unfortunately it didn't come with an oil cooler, but I was able to find one at www.outdoordistributors.com - http://tinyurl.com/9z75c
to assist in keeping it cool. Of course as has been stated, most engines like these have been designed to run at their full throttle setting in order to stay cool. Also, if equipped, to keep the battery charged.