looking for recommendation on hand held tachometer for engine tuning

Outobie

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Jul 6, 2017
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7
Hello all I'm in need of a good (accurate) hand held tachometer and thought I would see if you all had any recommendations.

I have a pair of 2001 5.7 alpha 1 motors with 2bbl carbs and thunderbolt V ignition, if it matters.

I want to dial in my idle speed with something more accurate than the helm tachs which seem way off by the sound of the motors and also be able to just compare how off my tachs really are.

I'm not a commercial mechanic so I don't need a $1000 snap-on tach just somethign basic, accurate and inexpensive.

brand and model info for recommendations is appreciated.

thanks
John
 

Bondo

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Apr 17, 2002
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Ayuh,..... Welcome Aboard,...... I bought an Inova digital timin' light a few years ago at my local Napa,......

I Love it,.... Timin',.... Rpms,.... Dwell,.... Does it All,.....
 

alldodge

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Agree it does it all, but for just a tach, get one to read up to 10K rpms (thinking of the future), do 2 and 4 stroke motors and the latest is the photo type. Last one I bought (3 years ago) is hard wired, but now they have the photo type so no wires.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I have an $11 optical tach from amazon. I dont feel bad when it gets dropped in the bilge or in the garage..

the all-in-one timing light that Bondo mentions would be my recommendation for a one-tool that does it all.
 

scipper77

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Sep 30, 2008
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2,106
I have an old dwell meter that I picked up on craigslist years ago when I had a points style ignition. Did a nice job and was practically free since they are virtually obsolete for automotive use. Probably not what you have in mind but I like that it is an old analog device. I used it to set my dwell as well as my idle and had that old boat running like a champ.
 

Outobie

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Jul 6, 2017
Messages
7
I ended up getting a laser tach. The type where you put a reflective sticker on the crank and aim the laser at it.

worked great for setting idle
i found out that my old tachs are not very accurate at all.

laser shows Perfect idle at 650 on both motors while the tachs are at 500 rpm

i installed an engine synchronization gauge where my speedo was and now know that the tachs are off everywhere. At cruising speed with the synchronizer dead in the middle, port tach shows 200 rpm faster than stbd.

it shure would be nice to have accurate tachs!

is there an accurate remote tach I could use to test rpm from the helm while under weigh? I’m getting my props reconditioned and would love to be able to verify my actual WOT RPMs

ill replace my gauges once I am confident my gauges are the actual problem rather than wiring or signal.

one other thing is that my synchronizer is a new vintage VDO unit that matches the OEM gauges. It works great at my normal cruise speeds but when I tried to test at WOT it starts bouncing all over the place. On the box it says not for use with the Mercruiser thunderbolt electronic ignition (which is what I have) and that it’s made for points ignition. I don’t know how it would make a difference though. A signal is a signal I thought
 

Lou C

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Nov 10, 2002
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13,222
I have an Actron tach/dwell/volts/amps tester and a Craftsman advance timing light...
 

alldodge

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Unable to say why the synchronizer says its not for TB ignition, but I would accept the label from the manufacture.
 
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