Tachometer

[muskyjim]

I have 16 foot 1969 StarCraft with a 1979 70hp Johnson. I have a speedometer and a voltage guage for instrumentation. It all looks like the original configuration on the boat. Can anyone tell me if I should install a Tach and why I would need it.
Thanks.

 

[CATransplant]

Re: Tachometer

Someone will be along shortly to tell you that the tach is a must have item. I'm not that guy.

Still, it's good to know what RPMs your outboard is turning. It's helpful in choosing the right prop, how the engine is trimmed, and to know if you're lugging the engine.

Without the tach, you'll have to judge performance by ear, and that's not the best judge if you don't have lots of outboard experience.

On the other hand, if you're not planning to buy different props to get the absolute maximum out of your outboard, you probably don't need one.

It's your call.

You will hear from others, though, with different opinions.

 

[jmoorepghpa]

Re: Tachometer

Your two cycle motor is designed to operate within a certain rpm band at wide open throttle (wot). If you over rev the motor damage can occur and running below the specified rpm range at wot will carbon up the motor which comes from the incomplete combustion of the oil/fuel mixture. That causes damage as well if left untreated. The boat, load and prop selection will determine where your motor runs at wot. When I re-constructed the helm in my '76 Stuery I mounted the tach front-center right in the middle and eliminated the spedometer completely. I'm not sure what a spedo actually is good for in a boat unless you are a performance guy or do a lot of serious skiing. "Thou shalt not maketh a wake" and "Thou art allowed to maketh a wake" pretty much sums it up. A tach is in my book a must. If for instance your boat is set up to run with a full load and compliment and you are out running lightly loaded you can open up to wot and then trim the bow down to get a little more drag and bring the rpms down in to your ideal range for that motor. If you change props a lot or have an adjustable composite prop a tach is a must. This holds up for four cycle engines as well.

 

[Frank Acampora]

Re: Tachometer

I put a tach in all my boats for the same reason I put a trailer hitch on all my cars: They just look right with them. As stated before, if you are not serious about changing props a tach is not an absolute necessity.

Me? I am constantly swapping engines and props so a tach is a real nice instrument to gauge performance.

It also makes you look like you know what you are doing when you periodically look at the thing. A knowing grunt and a nod now and then helps too.

 

[delfinasul]

Re: Tachometer

I think is necessary just for giving you the "guilty feeling" when you look at him and see you are above the recommended range and you don't want to decrease the speed )


A.Cosmin

 

[muskyjim]

Re: Tachometer

I will switchout the speedometer for a Tach. My GPS gives the speed any way so I don't need 2 speedometers. Can you use any type of Tach, or does it need to be specific for marine/outboard use?
I'll see if my Clymer manual will tell me how to hook it up. If it doesn't I'll be getting back to you guys.
Thanks for all of the advice and info.
Jim

 

[ricksrster]

Re: Tachometer

iboats carries various brand name tachs for a very reasonable price. They are easy to install and come with installation instructions included.

 

[studlymandingo]

Re: Tachometer

let us know how the install goes!​

 

[muskyjim]

Re: Tachometer

Thanks all for the help.
Parts on order and I'll let you know how the install goes.
Jim