George 0 #1 Posted January 19, 2009 When setting up an engine do you have a tool or method that you use for measuring RPMs. I'm going shopping for some tools today and I'm curious as to what you guys like to use. In the past I have always made these adjustment by ear. Thanks Share this post Link to post Share on other sites
Coadster32 793 #2 Posted January 19, 2009 By ear is good most of the time, that's the method I use. Perhaps really fast eyes. You can also buy a tachometer that hooks around the firing wire. They are usually pretty cheap. Share this post Link to post Share on other sites
1117scooter 0 #3 Posted January 19, 2009 In my shop I have 2 types-the first is electronic and can do just about any engine cost about 150 at the time.The second one which worked great for years is the wire type available from your local briggs and stratton dealer they both work from vibration,I think they cost 10 -20 dollars Share this post Link to post Share on other sites
TT-(Moderator) 1,131 #4 Posted January 19, 2009 To add to Neil's answer.... The Briggs & Stratton "Vibratach" (treysit sirometer) is B&S P/N 19200. Most dealers never seem to stock them, but should be able to get them easily. They were close to $30 the last I checked, but everything else is getting more expensive too - so it's really no surprise. :thumbs: Share this post Link to post Share on other sites
sorekiwi 761 #5 Posted January 20, 2009 The Briggs & Stratton "Vibratach" (treysit sirometer) is B&S P/N 19200. The Vibratach is the one I use too, they're great. Think I paid close to $30 for mine about a year ago. Tecumseh offers it too, but they're made by someone else (I'm thinking German? Not going back out in the cold to check ). They are really accurate - put it on top of an electric motor and check the reading against the spec - it'll be within 20 rpm. I also have an electronic (digital) meter but it jumps around so much its useless. Share this post Link to post Share on other sites
Buzz 502 #6 Posted January 20, 2009 I'm confused I looked up the prices for the Briggs Vibratach #19200 and they ranged from Sohars $22.36 to over $30. I then noticed an ad for Tecumsehs Vibratach #670156 and they are cheaper. I copied the ad from the same supplier for both and printed them out to compare. Here's the Briggs for $29.05 http://www.manddsmallengine.com/briggs/tools/19200.html Here's the Tecumseh for $20.95 http://www.manddsmallengine.com/tecumseh/tools/670156.html What's the difference that would cause the price of the Briggs to be 50% higher I rechecked the prices and Tecumseh was always way lower. Parts Tree: Tecumseh $11.02 , Briggs $30.45 :wtf: Sohars: Tecumseh $11.36, Briggs $22.36 What am I missing? Share this post Link to post Share on other sites
TT-(Moderator) 1,131 #7 Posted January 20, 2009 What's the difference that would cause the price of the Briggs to be 50% higher I rechecked the prices and Tecumseh was always way lower. Parts Tree: Tecumseh $11.02 , Briggs $30.45 :wtf: Sohars: Tecumseh $11.36, Briggs $22.36 What am I missing? The B&S sirometer includes operation instructions in English. The one from Tecumseh doesn't. (I'm not actually sure if that's the real cause, but I have read that on many different websites. ) Share this post Link to post Share on other sites
linen beige 14 #8 Posted January 20, 2009 What's the difference that would cause the price of the Briggs to be 50% higher What am I missing? The Briggs will more likely get used on running engines. (Sorry Wild Bill.) Seriously though. Here's something to think about. I have an engine analyzer/multi meter combination with an rpm scale on it. These typically have readouts for 4, 6, and 8 cylinders. They count electrical impulses rather than vibrations. A four cylinder engine fires four times as often as a single cylinder engine (Disregarding those that fire on compression and exhaust.) If you have access to one of these meters use the four cylinder scale and multiply the reading by four. They cost two to three times as much as the vibra-tachs, but they are full function multi meters with a multitude of other uses. Share this post Link to post Share on other sites
WheelHorse_of_course 99 #9 Posted January 21, 2009 The Briggs will more likely get used on running engines. (Sorry Wild Bill.) Seriously though. Here's something to think about. I have an engine analyzer/multi meter combination with an rpm scale on it. These typically have readouts for 4, 6, and 8 cylinders. They count electrical impulses rather than vibrations. A four cylinder engine fires four times as often as a single cylinder engine (Disregarding those that fire on compression and exhaust.) If you have access to one of these meters use the four cylinder scale and multiply the reading by four. They cost two to three times as much as the vibra-tachs, but they are full function multi meters with a multitude of other uses. My Sirometer is the Tecumseh. It even came with a case. It is indeed made in Germany. I dropped it and it fell apart, but it went back together again pretty easily. If it happens again I will put a dab of glue on the friction rivet thingy and it won't happen again. Regarding the 4/6/8 cylinder engine analyzers. These won't work on the older electronic ignitions. Also I don't know if they will work on magneto ignitions (they certainly would not be adaptable to engines that have the points under the flywheel) I would also suspect that the divide by number would vary on the engine since some engines fire one per revolution (in other words fire redundantly at the end of the exhaust stroke) and some fire once every other revolutions (only at the end of the compression stroke). The sirometers are worthless for when operating the tractor, but perfect for tune up. They are also perfect for checking the RPM of implements - for example the pulley on my hammermill is too big, but I was able to learn where the correct throttle setting is and avoid a hazardous situation by checking its RPM. :thumbs: Share this post Link to post Share on other sites
linen beige 14 #10 Posted January 21, 2009 Rolf, I addressed the engines that fire on each stroke (such as lauson/Tecumseh). If your single cylinder fires on each stroke just multiply the four cylinder reading by two. My old (mid '70s Actron) analyzer/tach works by monitoring the positive lead to the coil. I have never tried it on a magneto ignition but the manual says it will work. It can be used on engines that have a magneto ignition with points and coil all housed beneath the flywheel provided you can run a connecting wire from the coil positive to the analyzer. This analyzer has five leads. Positive, ground, test/function, and a two wire amp shunt. It also works on the Delco-Remy type electronic ignitions of the '70s. Although capacitive discharge ignition systems with a seperate coil for each plug weren't around or at least not common when it was made, it WILL work on them. Simply connect it to any "trigger" lead. My newer Actron analyzer/meter only has two leads but works with several types of ignitions, magneto included. Share this post Link to post Share on other sites
Michael Bullington 5 #11 Posted January 21, 2009 heres a couple of options http://www.jackssmallengines.com/hour_meter.cfm http://cgi.ebay.com/TECUMSEH-Small-Engine-...%3A1%7C294%3A50 Share this post Link to post Share on other sites
qd-16 14 #12 Posted January 21, 2009 I have one of the Tiny-Tachs mounted on my wh. The lead wraps around the spark plug wire. Its supposed to read rpm's and have a hour gauge on it. I haven't had very good luck with it, the tach part will only work some of the time (jumps all over the place) but the hour gauge works alright. Kinda of pricey but I thought it was something I had to have at the time. Share this post Link to post Share on other sites