tiny tach and clones on outboards

jacoboregon · Nov 19, 2011

Have any of you used the 'tiny tach' or one of the clones on your outboard? I'm considering getting one to put on my pull-start tohatsu 40hp to see how it's running in regard to rpm's at wot. I'm wondering if anyone has experience with accuracy and longevity.

I understand it is only 'water resistant' so will need to be mounted as dry as possible.

jacoboregon · Nov 19, 2011

tiny tach and clones on outboards

Have any of you used the 'tiny tach' or one of the clones on your outboard? I'm considering getting one to put on my pull-start tohatsu 40hp to see how it's running in regard to rpm's at wot. I'm wondering if anyone has experience with accuracy and longevity.

I understand it is only 'water resistant' so will need to be mounted as dry as possible.

F_R · Nov 19, 2011

Re: tiny tach and clones on outboards

If you are only going to use it for diagnostic purposes, I suggest a laser tach. Just point it at the flywheel. Now that I suggested it, I'd better go get one for myself. I haven't tried one yet. But it sure sounds like the way to go. It should work on virtually anything that rotates.

John_S · Nov 19, 2011

Re: tiny tach and clones on outboards

http://forums.iboats.com/showthread.php?t=503496

Worked with my Nissan 40C, Merc 25, and Nissan 18E

John_S · Nov 19, 2011

Re: tiny tach and clones on outboards

See you thread in "boats".

jacoboregon · Nov 19, 2011

Re: tiny tach and clones on outboards

John_S said:
See you thread in "boats".

Thanks John

Scott Danforth · Nov 19, 2011

Re: tiny tach and clones on outboards

we use tiny tachs at work for all the R&D test units. they are water proof, somewhat shock proof, and nice to totalize hours.

jacoboregon · Nov 19, 2011

Re: tiny tach and clones on outboards

Scott Danforth said:
we use tiny tachs at work for all the R&D test units. they are water proof, somewhat shock proof, and nice to totalize hours.

Are they actually "waterproof" or only "water-resistant"?

Texasmark · Nov 20, 2011

Re: tiny tach and clones on outboards

My lawnmowers have digital tach's on them. They are setup for 4 cycle engines, but with the flywheel magneto, every revolution the magnet passes the coil so that tells me that you get a hit per rev which is just what you would get on your OB so the indicated rpm's should be correct. They are very accurate and couldn't cost very much since they are in a $1500 lawn mower.

The pickup is just a piece of small gauge wire wrapped around the sparkplug wire and they probably need 12v and gnd. That's it.

Mark

John_S · Nov 20, 2011

Re: tiny tach and clones on outboards

I haven't held it underwater, but has been soaked by rain with no problems.

justchecking · Nov 20, 2011

Re: tiny tach and clones on outboards

I put one on my log splitter 4 years ago. So far 155 hours of operation with lots of rain and vibration and no problems.

Bob_VT · Nov 20, 2011

Re: tiny tach and clones on outboards

There is no reason to post the same question in multiple parts of the forum. Your threads were merged.

steelespike · Nov 20, 2011

Re: tiny tach and clones on outboards

The lazor tach can be difficult to use in a moving boat.

jacoboregon · Nov 20, 2011

Re: tiny tach and clones on outboards

Bob_VT said:
There is no reason to post the same question in multiple parts of the forum. Your threads were merged.

Thanks. That's why the first one was edited to say it was mistakenly put in the wrong forum.

jacoboregon · Nov 20, 2011

Re: tiny tach and clones on outboards

steelespike said:
The lazor tach can be difficult to use in a moving boat.

I would think. That's why I haven't considered it as an option.

I believe I'm going to go with the tiny tach. I've seen other makes that are cheaper, but that's also my worry!

John_S · Nov 21, 2011

Re: tiny tach and clones on outboards

I see they have a new TT2A that handles multiple engine config. When I looked at TT, you had to buy specific ones, for your engine. So with TT2A, it wouldn't matter if your tohatsu is a 4 stroke or 2 stroke.

Is saw this in their lit:

NOTE: Some engines, such as multi-cylinder outboards generate considerable electronic "noise" and may require a light filter to assure a clear RPM reading.You will find a "comments" section at the end of the order page where you can tell us about your engine ? what kind and how many cylinders it has ? so that we can make any necessary adjustments.

laotou · Nov 21, 2011

Re: tiny tach and clones on outboards

I got a clone version of the Tiny Tach from eBay around $10. The seller was at Hong Kong. The tach does not even have a brand. It has only one wire that wraps around the spark plug wire. It does not have the ground wire. Below 3000 rpm, the reading seems to be stable. When the rpm is above 4000, the reading fluctuates like crazy. So, it may not be suitable for measuring rpm at WOT.

Many iboaters complained that one cylinder did not fire. I did a test on my motor. I wrapped a piece of wire on each spark plug wire and ran my boat under load at about 3000 rpm. The readings of all cylinders were within 5%. I knew that all the spark plugs were working.

Another shortcoming is the display. It has a very narrow viewing angle.

jacoboregon · Nov 21, 2011

Re: tiny tach and clones on outboards

laotou said:
I got a clone version of the Tiny Tach from eBay around $10. The seller was at Hong Kong. The tach does not even have a brand. It has only one wire that wraps around the spark plug wire. It does not have the ground wire. Below 3000 rpm, the reading seems to be stable. When the rpm is above 4000, the reading fluctuates like crazy. So, it may not be suitable for measuring rpm at WOT.

Many iboaters complained that one cylinder did not fire. I did a test on my motor. I wrapped a piece of wire on each spark plug wire and ran my boat under load at about 3000 rpm. The readings of all cylinders were within 5%. I knew that all the spark plugs were working.

Another shortcoming is the display. It has a very narrow viewing angle.

Thanks for information. I'm going to get the tiny tach. I thought about one of the Hong Kong ones, but read poor reviews about the seller, and iffy reviews about the product. I'm not sure if that's the same as yours or not. Usually it's less in the long run to spend a little more initially.
Thanks! I appreciate everyone's input.

ronsealdeath · Dec 19, 2011

Re: tiny tach and clones on outboards

I too considered a Hong Kong tach similar to the Tiny Tach. In the end I junked the idea of a digital tacho on a boat as I just couldn't get over having to read a digital display over an analogue clock display. I reckon I'd rather have an analogue one any day becauser they look nicer and are a lot easier to read at a glance when your bombing along at high speeds with skiers, boaters and sail boats possibly around. Thats just my opinion though. Be aware that the Hong Kong tachs only have short leads so you may end up having to mount them on the engine hood or somewhere near the rear of the boat and that's pretty useless at WOT!

jacoboregon · Dec 20, 2011

Re: tiny tach and clones on outboards

ronsealdeath said:
I too considered a Hong Kong tach similar to the Tiny Tach. In the end I junked the idea of a digital tacho on a boat as I just couldn't get over having to read a digital display over an analogue clock display. I reckon I'd rather have an analogue one any day becauser they look nicer and are a lot easier to read at a glance when your bombing along at high speeds with skiers, boaters and sail boats possibly around. Thats just my opinion though. Be aware that the Hong Kong tachs only have short leads so you may end up having to mount them on the engine hood or somewhere near the rear of the boat and that's pretty useless at WOT!

Actually, the lead is quite long enough for my inflatable. It's about 10' long, which gives my the option to mount it easily anywhere in my boat within easy reading distance. (I guess that is short if you're in a 20' boat, but we're talking sib's)
Why would you want to look at your tach while passing in close vicinity to other boaters and sail boats? You should be paying attention to your driving. There is really no need to ever look at your tach while at WOT unless you are setting up a prop. Once you have the right prop (which you wouldn't know without a tach) you really don't need to keep looking at the tach.
I'm very happy with this tach, and it is VERY easy to read the digital numbers.

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