Looking to install a few gauges on my 1983 175hp and good use some quick tips

1983 175hp sea horse

have most wired and good to go, but i do have a couple questions on a few:

Tach: is the grey wire on the oem three pin to the oem tach the sending wire that needs to go to the new gauge? gauge instructions say to set the tach to "5" setting, yet old gauge was at the "6," is this standardized, or do the values change from brand to brand?

Trim: off the tilt/trim control box comes a harness that had two wires going to the old gauge. One is white and the other black. am i ok just hooking the white one to the gauge, or does the black one serve a purpose beyond providing the ground? (i have all gauges wired already except the sending units)

Water temp: is there an oem location to remove a bolt and install a standard 1/8" npt sending unit, or would this require a drill and tap (i would prefer to avoid this)?

Water psi: is there an oem location to remove a bolt and install the feed fitting for the psi gauge, or should i just install a T in the pee hose between the motor and the outlet?

Thank you

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

Tach: yes, grey wire is the tach signal. I'm pretty sure the tach should be on 6 poles, what it's doing is counting pulses from the stator and I believe there are 6 magnets on your flywheel.

Trim: There should be 3 connections on the trim gauge (not counting the ones for a light if your gauge has that). "I" gets power, "G" is ground, and "S" comes from the sender. And on the trim sender one wire is grounded and one goes to the gauge (the "S" terminal).

Water temp: On some heads there's a threaded thermo-well that can be used for a temperature sender and on some there isn't. If not then Faria makes a temp gauge with a sender that can be mounted under a head bolt.

Water pressure: You'll be fine just T-ing it in with the tell-tale.

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

metriccrescentwrench said:

Tach: yes, grey wire is the tach signal. I'm pretty sure the tach should be on 6 poles, what it's doing is counting pulses from the stator and I believe there are 6 magnets on your flywheel.

Trim: There should be 3 connections on the trim gauge (not counting the ones for a light if your gauge has that). "I" gets power, "G" is ground, and "S" comes from the sender. And on the trim sender one wire is grounded and one goes to the gauge (the "S" terminal).

Water temp: On some heads there's a threaded thermo-well that can be used for a temperature sender and on some there isn't. If not then Faria makes a temp gauge with a sender that can be mounted under a head bolt.

Water pressure: You'll be fine just T-ing it in with the tell-tale.

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thanks, im just wondering where do i even look for the threaded hole for the water sender to mount? not really sure where to look

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

the beloved trim gauge is the only one not working so i am going to have to see if the sending unit in the box is dead.

also i just received my two head temp sending units, wondering if the tip of the sending unit should be in contact with the head, or should there be a little space between (i have seen conflicting info on this and there were no directions with the senders)? also should i chip paint off the head at this location?

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

Let us know how the sending units and guages work out for you. I want to do this also and will follow your advice. thanks!

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

You will want the flat tip of the sender in hard contact with the head. I sanded the paint off just under the tip. If I had it to do over, I wouldn't worry about sanding the paint. I disconnected my telltale and plumbed the water pressure gauge direct to the hose barb. You can try that way and also with a "T" in the line. Check/compare the pressure readings both ways, then decide which hookup give the strongest pressure reading.

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

emdsapmgr said:

You will want the flat tip of the sender in hard contact with the head. I sanded the paint off just under the tip. If I had it to do over, I wouldn't worry about sanding the paint. I disconnected my telltale and plumbed the water pressure gauge direct to the hose barb. You can try that way and also with a "T" in the line. Check/compare the pressure readings both ways, then decide which hookup give the strongest pressure reading.

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any special reason you wouldnt have sanded the head?

also i am just wondering is there any trick on how to determine the tach "setting" without taking the flywheel off and counting the magnets?

oem part # for the stock flywheel is 0582403

the aftermarket tach that came with the motor was set to 6, faria instructions listed the motor to be set to 5 i believe. again, 1983 175hp sea horse. thanks

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

i am not trying to be a pain on this question but i am getting some conflicting info from faria on the tach install compared to common sense and basic understanding. the faria install instructions list my motor with 12 poles (correct), but on their chart list 12 poles should be on setting "5," while everything i see elsewhere says it should be on setting "6." im kind of baffled bc i wouldnt expect a company like this to make a mistake like this and not update to the correct information

here is a link to the information and instructions:

http://www.google.com/url?sa=t&rct=...-Y5w1HVMkXGtsjHWELBS58g&bvm=bv.46751780,d.aWM

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

I understand your frustration with the tach setting. Your engine has 12 poles on the alternator. That has no direct bearing on the tach setting. I have used tachs from these companes: OMC, Medallion and Teleflex. Their instructions all said to set the tach pointer to the number 6 for a V4 or V6 OMC. At that setting the tach will count the stator pulses correctly. It's a pretty standard setting in my humble opinion. I suppose it is possible that the Faria company may specify a setting of 5 on their tachs for the 12 pole alternator. Faria is a solid/reputable manufacturer of gauges. If you purchase/own their tach, I'd follow their installation instructions for the pointer setting.

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

emdsapmgr said:

I understand your frustration with the tach setting. Your engine has 12 poles on the alternator. That has no direct bearing on the tach setting. I have used tachs from these companes: OMC, Medallion and Teleflex. Their instructions all said to set the tach pointer to the number 6 for a V4 or V6 OMC. At that setting the tach will count the stator pulses correctly. It's a pretty standard setting in my humble opinion. I suppose it is possible that the Faria company may specify a setting of 5 on their tachs for the 12 pole alternator. Faria is a solid/reputable manufacturer of gauges. If you purchase/own their tach, I'd follow their installation instructions for the pointer setting.

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you just documented my issue well ha, so i have sent an email to faria about their tach instructions

and did you see my earlier response/question to the temp sending units?

repost:any special reason you wouldnt have sanded the head if you had to do it over?

also how susceptible are those head studs to breaking? this motor has been is the salt water before so there is some corrosion/surface rusting on motor. i am concerned that the risk/reward of trying to remove two head studs to install the two temp sending units may leave me with two broken studs and a huge mess. any other ideas on what motor bolts to possibly use that do not present the same risk? i just find it always better to ask bc someone may have a better idea or trick

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

Bottom line on sanding the contact spot on the head under the temp sender: I don't think that a few mils of head paint will affect the heat transfer to the sender at all. I would probably not pull a head bolt to mount the temp sender. There are smaller bolts on the head, the ones for the head cover. Pull one of them out and use it for mounting the sender bracket.

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

I agree with emd on not using a head bolt, but rather one of the cover bolts. On the 83' they do have a small flat space on the head covers that appears to be dedicated to locating a temp sender.

When I get a chance I will take a pic and show you my head covers. I have a temp sender in each one. I just went ahead and tapped/threaded mine. The installed nicely with some thread tape, and arent as clunky as the bracket system pressing it up against the plate. But I guess that is just a personal preferance. I know they are "in" the water and getting a true temp reading.

Re: Looking to install a few gauges on my 1983 175hp and good use some quick tips

thanks. i ended up using two cover bolts for now. i may eventually tap them but not for now. the senders are located right below the top spark plug on each bank

separately, here is the convo i had with faria which ended up with them telling me to use setting 5 on a 12 pole system which i found interesting. glad i asked them so i have the proper setting:

hi, i have a question regarding your 7k rpm tach install instructions. on the provided instructions it states that outboards with 12 poles should have the tach set to setting "5," yet everything i read elsewhere states that omc motors with 12 poles should be on setting "6." im trying to figure out if there is an error on the instructions provided with the tach from faria or if your tachs are designed different somehow. thanks

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Hello,
Only E/J OMC system check type Faria tachs have setting 6. For 12 pole. All other 7000 RPM tachs use setting 5 for 12 pole. Teleflex tachs use setting 6 for 12 pole also.


Regards,
Jason

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System check you are referring to the buzzer chrip when turning the ignition key on? I purchased you marpac premiere 7k tach. I have a 1983 175hp sea horse. Just trying to figure what setting I need to have the tach on. Thanks

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Hello,
12 pole setting #5.


Regards,
Jason