Tachometer on a '57 35 horse Johnson.

rolmops

rolmops

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Hello<br />I am planning to get an original 1957 tachometer to work on my boat together with my '57 seahorse.<br />Can anybody tell me how to hook the wiring on to the engine?<br />Your answers will be much appreciated.<br />Thank you, Rolmops.
 
oldboat1

oldboat1

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Re: Tachometer on a '57 35 horse Johnson.

Rolmops -- can't address your specific question about hook-up, but wanted to mention that the tach you find might be a two-piece model. I had an Airguide tach ('60s, I think) that I could never quite get to work on a newer model motor, but it had a solid state unit that went behind the dash. If you find a period model for your '57, be aware that it might need that second little unit in order to work.<br /><br />(Maybe some technical explanations will be forthcoming from other listers....)
 
rolmops

rolmops

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Re: Tachometer on a '57 35 horse Johnson.

Hello.<br />Thank you Oldboat,I knew there was a solid state electric circuit involved, but I had no idea that it might be a second unit in addition to the gage<br />I guess I should be a bit more specific.<br />The 35 in question is an rde 19 shortshaft with electric start and generator.<br />thanks.
 
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Lark40

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Re: Tachometer on a '57 35 horse Johnson.

If you decide not to go original, but just to have an accurate tach on that engine, I would recommend the TinyTach product.
 
rolmops

rolmops

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Re: Tachometer on a '57 35 horse Johnson.

How about if I hook it up on top of the wire that hooks onto the cutout switch assembly and then just ground the other wire on the block?
 
oldboat1

oldboat1

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Re: Tachometer on a '57 35 horse Johnson.

still hangin' in there with you, Rolmops. I want to see what the answer is too. The old tach I had came with four wires, as I recall. It sounds like your two wire connection should be a little more straightforward. <br /><br />It happens I just picked up a '57 cover for the transom box and have it in front of me (got to get a life....) I see black to ground. I also see brown, yellow and blue (all unconnected in this model -- no regulator, just the solenoid). Is one of those three wires free after your generator is hooked up? I'm thinking that might be a tach lead.<br /><br />will continue to watch this.
 
rolmops

rolmops

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Re: Tachometer on a '57 35 horse Johnson.

Hello oldboat.I much appreciate this.<br />The yellow one is field, and the blue is armature of the generator.Brown is the power supply from the regulator.So no free rides there.<br />My tach,which as it turns out is an airguide as well, also has four wires,but two of those are for the little lamp inside.<br />Thanks for your support.
 
L

Lark40

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Re: Tachometer on a '57 35 horse Johnson.

I had this same question out on the BoaterEd forum several times last year. No easy answers due to the distributor-less setup. Our ignitions are more similar to a leaf blower than to an automobile or modern outboard.<br /><br />Final answer I got was to find a tach which was designed for two-strokes and uses inductive sensing (wrapping the sensor wire around the plug wires). The TinyTach was the only low-priced product that offered these features. Of course, it won't look good in a judged show boat...
 
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sho305

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Re: Tachometer on a '57 35 horse Johnson.

I bought an EZ-TACH ES325 tach for testing. It is handheld and clamps on the wire like a timing light. You can use it on about any 2 or 4 stroke and is digital. About $50. I have found it does not like it when the wires are close together like an OB, so I have and old wire I hook in to get it away. I had to check my tach so I could prop right, now I'll check the new motor in my lawnmower...most things only need to be checked, but I was amazed at the lack of products in this area.
 
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