universal gauges, tach and mercury engine?

[stackz]

ok, wanting to completely redo my gauge panel while I redo the wiring on the boat. its got old mercury quicksilver gauges and apparently people want like $100 just for the stupid tach.

I like all my gauges to work and match.

why the hell should I pay $100 for a stupid tach gauge???

I see teleflex sets go for $140. after adding in a few extra gauges I want, I should be at around $200-$230 or so AND they'll all be brand new....and look better.

anyway, what gauges should I look for exactly (ones that use mercury senders I would think) and how do I determine what type of tach I need??

so far tach wise I've just gotten pics of the front back and matched to my old one. no clue how to tell what pole I need, etc.

 

[Silvertip]

Re: universal gauges, tach and mercury engine?

All we know is that you have a Mercury engine. Is it an outboard or an I/O, two stroke or four. It makes a difference what gauges you need.

For an outboard: Typical sets include Tach, Speedo, fuel, and voltmeter. Water Pressure and Water Temp are desireable. Water pressure tells you the water pump is working but does not tell you whether the engine is overheating or not. Therefore the water temp gauge is desireable. You need a temp sender for an outboard that matches the gauge.

For an I/O: Tach, Speedo, water temp, oil pressure, voltmeter, and trim. The outdrive needs a trim sender. The engine needs an oil pressure and water temp sender to match the gauges.

Fuel gauges are universal and require a 30 - 240 ohm fuel tank sender.
Tachs are universal for most outboards but you need one for an I/O if a universal does not support the I/O engine.

 

[stackz]

Re: universal gauges, tach and mercury engine?

sorry, 1988 M90 2-stroke 90hp engine

I want to get the following:
speedo/tach
voltmeter
trim level
fuel gauge
water temp/pressure
oil pressure

I was looking at the teleflex series gauges that use mercury sending units. I've got one of those magnetic 320ohm fuel level senders as well.

I'm just confused mainly on the speedo and the tach. speedo I have no clue how they even are set up. on cars you have a drive gear in the transmission and a driven gear for the sender (unless electronic)...on a boat...no clue lol.

also, the whole thing with the poles on the tachs...my engine is a 3-cylinder but all the tachs I read about say 2/4/6 cylinder??

 

[Chris1956]

Re: universal gauges, tach and mercury engine?

Stacz, no oil pressure in 2 cycle motor. If that is a inline six engine, it has no thermostat, so water temp is almost unusable. Motor likely has no trim sender, and no provision for one.

Stick with tach, Speedo, voltmeter, water pressure and fuel.

 

[Silvertip]

Re: universal gauges, tach and mercury engine?

You have a two stroke engine -- there is no oil pressure! You also don't need a trim gauge. You can turn your head to see the engine. Your seat of the pants tells you what proper trim is. Besides, trim settings change depending on load. Trim gauges are primarily used on boats where you can't see the engine or outdrive (pontoons and I/O's).

 

[Silvertip]

Re: universal gauges, tach and mercury engine?

You have a two stroke engine -- there is no oil pressure! You also don't need a trim gauge. You can turn your head to see the engine. Your seat of the pants tells you what proper trim is. Besides, trim settings change depending on load. Trim gauges are primarily used on boats where you can't see the engine or outdrive (pontoons and I/O's).

You are looking at the wrong stuff. Universal fuel gauges need a 33 - 240 ohm sender -- end of story. You need to change the sender. You are looking at auto style tachs which don't work on a two stroke engine. Two stroke tachs are universal and don't care how many cylinders the engine has as they work on stator pulses and can be set accordingly. Yours would be 6P.

A speedometer is not an electrical device. It needs a pickup (called a pitot) at the back of the boat. A small tube connects the pitot to the speedometer. As the boat passes through the water, pressure builds in the tube which makes the speedometer increase.

 

[stackz]

Re: universal gauges, tach and mercury engine?

yeah but its got a trim gauge now as it is (sensor is on the pivot point on the engine) so I'd like to keep that.

I've gotten used to knowing the little spot on the trim gauge that keeps the boat perfectly planed and not leaning.

I figured there was no oil pressure on a 2-stroke but didnt know if there was something that went inline from the oil injection tank or not.

anyway, how do I determine what type of tach I need?? I've seen some that have like a million pole positions and some that only have 5-6 or so. this is my first time dealing with marine gauges so its my learning curve..

edit: 6P tach, got it.

edit #2: how did you come to the conclusion on the 6P (P=pole right?) just trying to learn for future reference.