Replacing the Tach

[infideltarget]

Used the search function, didn't find one like this. I just bought a 1990 Four Winns 200 Horizon with an OMC 5.8 (Ford 351w) v-8 stern-drive. At some point in time, someone has replaced the factory tach with one from a Sea Ray. I do not know if it works, but it sure does not match the rest of the gauges. I located a factory tach from a 1990 Four Winns 190, that matches my gauges, but it is from a boat powered by an OMC 4.3 (GM) v-6 application. Will it work on my v-8 boat? Or did Four Winns install engine specific gauges?

 

[Silvertip]

Re: Replacing the Tach

Tachometers are fairly generic and have settings for I/O as well as outboards. If you look at the back of the tach there should be a dial or jumper settings for the various engines. Outboards will use setting for 5P or 6P. I/O engines are driven by the ignition system so they are number of cylinders dependent. There should be a setting for 4, 6, 8 cylinder. It doesn't matter who built the engine. The tach doesn't care. I'm guessing the tach you have will work. You will need to change the setting from 6 cylinder to 8 cylinder. If you are unsure about this, post a picture of the back of the tach and we will decipher things for you.

 

[infideltarget]

Re: Replacing the Tach

Thanks for the info. I ordered the matching tach today, and will get some pics of the back when it arrives.

 

[infideltarget]

Re: Replacing the Tach

No pics, but it does have a knob on the back with 1,2,3,4,5 marked on it, so I am guessing it is adjustable to engine pulses. Now I just need to research and see where to set it!

EDIT: ok...just read where pulses are from outboards. This tach is from a I/O boat. It is original equipment. Confusion prevails. Research continues.

 

[Silvertip]

Re: Replacing the Tach

Isn't there a legend on the back of the tach to relate what the 1-5 settings equate to? Go to the web site for the manufacturer of the tach. They should have instructions posted on the web site. You know nobody that has a digital camera that can post a picture? Outboard engines get their tach signal from the stator that is the heart of the charging system. Most late model outboards have a 12 pole alternator that produces 6 pulses. Automobile engines are four strokes and the tach signal is derived from the ignition system which IS number of cylinders dependent. A 4 cylinder auto engine produces 2 pulses /rev, a six cylinder produces 3 and a V8 produces 4. The tach I looked at just last evening at Cabelas had a legend printed on the back to relate calibration for two strokes and four strokes.

 

[infideltarget]

Re: Replacing the Tach

Isn't there a legend on the back of the tach to relate what the 1-5 settings equate to? Go to the web site for the manufacturer of the tach. They should have instructions posted on the web site. You know nobody that has a digital camera that can post a picture? Outboard engines get their tach signal from the stator that is the heart of the charging system. Most late model outboards have a 12 pole alternator that produces 6 pulses. Automobile engines are four strokes and the tach signal is derived from the ignition system which IS number of cylinders dependent. A 4 cylinder auto engine produces 2 pulses /rev, a six cylinder produces 3 and a V8 produces 4. The tach I looked at just last evening at Cabelas had a legend printed on the back to relate calibration for two strokes and four strokes.

There is no legend on the back of the tach. I do not know who made the tach, as it came out of a Four Winns boat...but I am guessing probably Teleflex. I do know how automotive engines send signals to the tach, but I am not familiar with the two stroke side of things, and am not really concerned about two stroke stuff at this point. My confusion arises at how this particular tach interprets the siganls, and where to set it. I am not anywhere near the boat right now, so It is not a huge issue, but I would like to know how it references. I did see another thread that you posted in, that the guy took the cover off of the tach and there was a switch for 4, 6, 8 cylinders inside. This may well be the case, but my wife is not comfortable with taking it apart. I am not too concerned with taking a pic right now, because she described it to me in detail, and there is no switch visible other than the knob and the 1-5 notches. It arrived set on '2', but it came from a v-6 OMC Cobra set up, so I am guessing someone turned the knob, and it was probably on '3' when it came out. I do appreciate your advice, and will post up on this again when I get back stateside later this year. In the meantime, I will be trying to find out who in fact made this tach, and see if there is some sort of literature on it for me to look at.

 

[infideltarget]

Re: Replacing the Tach

I located some material on this tach. I think it was made by Medallion, and the 1-5 settings are as follows: 1= 4cyl, 2= 6cyl, 3= 8cyl, 4= 10p, 5= 12p. So I am guessing that all I would need to do is move the dial from 2 to 3, and I should be good to go. I located this information on a listing on eBay for a set of factory Four Winns gauges from 1990. Please someone tell me if I am wrong on this info.

 

[Four Winns Erie]

Re: Replacing the Tach

Your info is correct. I checked the back of my tach and there is a sticker with that exact info on it. Mine is set on #2 for my 6 cylinder engine.