Logo
FULL SITE MENU

Tachometer Question For JerryJerry

topgun3690

topgun3690

Member
Mr Jerry.....my tach started acting up recently. When the engine is shut off sometimes the tach still shows like 500 rpm. Start the engine and it stays the same, slap the dash near the gauge and it will jump up to a higher rpm. Once underway it seems to work ok. It doesn't do this all the time but I am begging to wonder how accurate it is now. Part # for the tach is F5H012 and several are available on Ebay if I need to replace it. Have not done anything with it yet....wanted to get advice on what to look for first......maybe corrosion, bad connection, wiring, etc. Not sure where the tach gets it's info from so maybe a problem with that?? Thanks.
 
I believe the grey lead in the wiring harness is for the tach.

Being as you have a Chrysler in your pic and it at least 25-30 years old , I'd say the tach is a 12 or 20 pole tach.
You need to remove the flywheel and count the lugs on the stator.


And yes the connectors can be bad.
WD-40 or maybe a contact cleaner?
Spray the contacts, undo the screws or the plug.
Spray in the key switch at the same time, then activate the key with the battery disconnected.
Activate the choke at the same time.
WD helps clean the contacts.
Undo the screws on the wiring terminal block and spray with WD.

The tach itself, it's OLD and might need to be replaced.
On the back should be a black arrow/dial, remember where it was set.
Turn it and spray with WD.
Good luck, keep us posted when you get it fixed.
 
Jerryjerry05 said:
I believe the grey lead in the wiring harness is for the tach.

Being as you have a Chrysler in your pic and it at least 25-30 years old , I'd say the tach is a 12 or 20 pole tach.
You need to remove the flywheel and count the lugs on the stator.


And yes the connectors can be bad.
WD-40 or maybe a contact cleaner?
Spray the contacts, undo the screws or the plug.
Spray in the key switch at the same time, then activate the key with the battery disconnected.
Activate the choke at the same time.
WD helps clean the contacts.
Undo the screws on the wiring terminal block and spray with WD.

The tach itself, it's OLD and might need to be replaced.
On the back should be a black arrow/dial, remember where it was set.
Turn it and spray with WD.
Good luck, keep us posted when you get it fixed.
Click to expand...
Yes sir, it is old. 41 years old. I will check the things you mentioned and go from there. I had just replaced the ignition switch so don't think that is the problem as there was no change in the tach operation. Will post later with results. Thanks.
 
In regards to your suggestion of removing the flywheel to count the lugs on the stator.....this website(marineengine.com) has the correct stator for my motor.............part number F85095-2...with a good pic of it....it shows 12 lugs....does this mean I would need a 12 pole tach? Just trying to avoid removing the flywheel as I have read posts on here where folks had a hard time taking them off and caused damage in the process.
 
You can try to look under the flywheel and count the lugs??
According to the parts specs it's a 12.

Removing the flywheel can be tricky.
And sometimes almost impossible.
 
Yes.
Sometime in the 80's they decided to change something that worked for YEARS
to something "better".
Then in the mid 90's they changed back.
Actually they started using Mercury ignition systems.
 
s-l225.webp
Is this the tiny tach you recommend?
 
Last edited:
Disregard that last post! Lol Ebay item #223113026478 Is this the tiny tach you talk about? May need one soon. Thanks.
[FONT=&quot]223113026478[/FONT]
 
Yes that's one of many.
eBay "tiny Tach" and 171 shows up.
From $7.49 (China) to $83.
I remember paying $16

Try to get one that the battery can be replaced.
The first ones made didn't have that option.
It lasted a few years then the battery went dead(trashed).

If your stator is a 12p then any 12 might work.
In some cases they sell a 6p that has a switch that doubles t a 12p
 
Glad it wasn't too bad for you over there.....Well, I removed the tach today and checked the connections and overall condition....found no corrosion or loose connections or bad wires. So I then proceeded to disassemble the tach and sprayed pookie (contact cleaner) on the innards and blew it out with compressed air. Put WD40 on the moving parts. Reassembled and reinstalled....worse than before. Lol So I will be buying a new or used tach. My boat has Medallion Instruments Inc gauges (original) and there was no part number anywhere on the old tach. I will try to post some pics. My factory service manual says the Chrysler tach for my engine is part #5H012. Several on ebay. Where would you look and what would you do to replace an old tach like this??
 
Did you count the lugs on the stator?
Myself, I wouldn't buy anything without knowing that???
The replacements: eBay or any marine dealer.
Google "marine instruments" and see who pops up?
Teleflex, Faria, ?
Just make sure the one you buy is for a 12 or 20 pole which ever you have??

Buying used gauges?????? I never do.
 
OK, thanks....the Chrysler tach # 5H012 I found on ebay are NOS, in a box. Most of the brand new tachs I have found have wiring harnesses that plug into the tach. Not sure how that would work since I only have 3 wires going to mine, a ground, signal, and one for the light.
 
I have a 12 lug stator for sure. Took your advice and looked for NEW tachs and think I may have found one that will work for my engine...Faria Beede 7000 rpm #33718. For universal outboard engine use, has a switch on the back to set pulses per engine revolution. Is the same size as my old one and even looks the same. As a Chrysler/Force guru would you mind taking a gander at this tach and see if you think this one will work for my engine?? Ebay item #352666309685. Thanks.
 
Saw the add on eBay.
Looks good but I didn't see anything that says "12pole"
Contact Faria and ask them. Better safe than sorry
It is for an outboard.
 
Just called and talked to Faria tech support.....they said there is a setting on the back of the tach specifically for 12 Pole applications. And the only difference in wiring it up from my old Medallion tach is the new one has a BATT terminal that requires a wire hooked up to a 12v circuit activated by the ignition switch. Sounds easy enough. Think I will go ahead and order it and put it in. Will post results later...thanks for the advice. And I hope yall are fairing well after the storm.
 
FYI....Faria also said they no longer make any tachs for 20 pole systems. It will take a week or so for the new tach to get here. Will post back later after installing, hopefully with good results. Thanks.
 
Yea I had heard Faria no longer made tachs for the 20 pole.
I guess that making something that works on a motor that's no longer made isn't
worth the $$.
 
The new tach finally arrived and got it installed today. On the hose in neutral at idle showed around 600-700 rpm, the same as the old tach before it went south. Still need to get it out on the water and open it up to see what the high end looks like but I feel like my tach problem has been solved. Ended up getting a Faria Beede Euro tach designed for all outboards. Was able to use the original ground and signal wires....had to add a wire for the Batt terminal on the new tach, ran it to the "I" terminal on the ignition switch....had to modify the wire for the tach light by cutting off the bulb socket and adding a 1/4 inch female spade terminal that just plugs into a male terminal on the back of the tach. Also has a setting for "12 pole" applications which I needed. And it fit in the original hole in the instrument panel perfectly. So.....Mr. Jerry, I really appreciate your input on this and will give another update after running the boat on the lake. We had a direct hit with TS Imelda yesterday so the weather is not so good for getting out on the water right now.
 
Glad it's working.
Now set up the idle, adjust the air screws then add a filter between the carb and the fuel pump.
Fram G2 G3 G12 work well.
 
Took your advice a while back and installed a filter between the pump and carbs. Right now this thing is running so good it's scary. Lol. Hate to mess with the carbs or anything else unless a clear problem arises. And if it does, I will be back on here asking for your advice, again. Have a good one, sir.
 
Back
Top