Installing a temperature gauge worth it or not

[MickLovin]

HI again, sorry to ask so many questions, but is it worth putting a temp. gauge on my Chrysler outboard, I know the buzzer definately works but not sure if the sender works or how to test it, does it have an Ohm reading? Every time I have tried to either put a tell tale in or a sender into the hole above the thermostat housing where the s/s flat head grub screw is, I have been unable to take out the grub screw. I have used heat and a centre punch tap so as not to stuff the flat blade screw head. I have had 4 Chrysler motors all with the same problem of trying to get the grub screw out but with no luck. :indecisiveness::noidea:

Ok question, is there an easy solution to this, remembering I have used heat, Penetrol and a impact screwdriver all to no avail, has anyone tried using the freezing solution and does it work??? To be honest I would prefer to have both Gauge and buzzer. So any help here is much appreciated. Also I believe the buzzer goes off at 160 degF? would you get a gauge from my thermostat opening which is a 110deg F, so 40 deg F to 160DegF ??

 

[pnwboat]

Re: Installing a temperature gauge worth it or not

The sender for the buzzer is a Bi-metal on/off switch. There is a metal strip inside the sending unit that has been calibrated to expand at a set temperature. When it does, it shorts the wire connected to the sending unit to ground, thus completing the buzzer circuit and energizing the buzzer alarm. The case must be grounded to the head in order for it to work. You can test the sender by heating it with a hair dryer, cigarette lighter etc. Check resistance between the case of the sending unit and the end of the wire that comes out of the sending unit. When it's cold, you'll read an open circuit. When you heat it up to the right temp., you'll read a short.

I installed a temperature gauge and have been happy with it. Unfortunately, the metal plug that you are referring to can be really stubborn and hard to remove. Heat with an impact screwdriver usually does it. The plug is usually made out of stainless steel. I don't know why, but stainless steel and aluminum in a marine environment can be a recipe for frozen fasteners due to corrosion. Patience and steady application of heat and cold will eventually get it done.

One thing you should be aware of. Most analog automotive water temperature gauges (at least here in the US) have a low reading of about 100?F (38?C). These Force outboards usually run at about 130?F - 140?F (54?C-62?C). I initially installed one of these types. What I found was that the needle barely moved as compared to when the motor was cold and warm motor. I later found a meter that read from 60?F-210?F (16?C-99?C). This worked much better. When the motor was running at 130?F, the needle was right in the middle of the temp. range on the gauge.

Good luck with that plug!

 

[gm280]

Re: Installing a temperature gauge worth it or not

Well another way to try and remove stubborn screws is to heat the surrounding area and cool spray the screw itself. Also try to tighten the screw even tighter and then try to loosen it. If all else fails, you could drill it our, re-tap the threads again and replace it. But before installing a new screw use some anti-seize on the thread to keep dissimilar metal corrosion in check.

 

[MickLovin]

Re: Installing a temperature gauge worth it or not

I always use antiseize, a copper based one although I heard there is a gel one which is better, I have 4 of these Chryslers and all have been nearly impossible to get out, but I will obtain the freeze solution and heat the outside as suggested as I haven't tried both at the same time, Thanks for the input gm280 and Thanks for the gauge info pnwboat, nothing better than first hand experience.

 

[Frank Acampora]

Re: Installing a temperature gauge worth it or not

Oh, No, Mick! Don't use copper anti-seize, especially in salt water. It sets up a good galvanic reaction. Use Nickel anti-seize. Some guys up here swear by Vaseline petroleum Jelly and others use RTV silicone. I must admit, I have seen the silicone and it does work very well on water pump bolts.

Now, if you really can't get out that stubborn screw you do have two options You can drill it and re-tap the hole but that is going to be sloppy. OR: Just behind the head is an odd shaped boss. That has plenty of meat. If you drill it right into the water jacket and tap to whatever your sender is it will work just fine. Here the senders (and the plug in the head) are threaded US 1/4 NPT (National Pipe Thread)

Now, you know you can not run both an overheat indicator and a temperature gauge on the orange wire. You must run a separate wire (Purple works) for the temperature indicator gauge.

It works almost the same way as the overheat indicator: Power is delivered to the gauge from the ignition switch. The "sender" is grounded on the engine block and its resistance varies with temperature. As it heats, more voltage is allowed to flow to ground and the gauge reads higher.

 

[Big Fish Billy]

Re: Installing a temperature gauge worth it or not

Something like this is nice, you just have to check into the sending unit...I wimped out and just bought the infared pistol type for all my applications, kinda nice.....

 

[Jiggz]

Re: Installing a temperature gauge worth it or not

I have read many threads regarding the temp gauge installation. I guess it makes a great addition to the driver's gauge board. Personally though I'd rather have a water pressure gauge. In fact, that is exactly what I installed from that t-stat plug. The gauge has a zero-30 PSI range and would indicate water pressure as high as 15~20 PSI at WOT. I love the pressure gage since it can indicate impending impeller problem long before it totally disintegrates and/or unable to pump water anymore. You can tell this by the pressure it puts out. Obviously, if the boat normally runs up to 15 PSI at WOT and the pressure seems to be going down each day or worse yet, cannot reach above 10 PSI anymore at WOT, it tells you the impeller is experiencing problem or the cooling system might be having problems.

Unlike the temp gage, wherein if you see the temp goes above normal, most likely the damage due to overheating could have already been done.

 

[pnwboat]

Re: Installing a temperature gauge worth it or not

I installed both a temp. gauge and a water pressure gauge. Like Jiggz stated above, it helps spot a problem before it becomes a show stopper, and it can sometimes help in diagnosing a problem. Of course, you have to look at them. I have my temp. and pressure gauges oriented so that when all is normal, the needles are all pointing straight up. When you're at WOT going across the lake, all you have to do is take a quick glance at them and not have to try and read the actual numbers.

 

[Justinde]

Re: Installing a temperature gauge worth it or not

Hey Mick

I used a left handed screw driver on mine. Dunno why it, but it worked..... ;-)

Seriously but, I chamfered the edge of my grub screw do that I could grab it with a shifter, plenty of WD40, and it finally cracked.

Cheers

 

[MickLovin]

Re: Installing a temperature gauge worth it or not

Thanks Just, I have tried everything but freezing it so I will try that before I destroy the head, and after reading this I may just go to a pressure gauge sounds like a better deal for impellor and problem sensing. Thanks guys for all the input.

 

[Justinde]

Re: Installing a temperature gauge worth it or not

BY the way- my 'grub screw' had a good 1" of real metal showing to play with..... I should have elaborated. If yours is nearly looking like a countersunk woodscrew in pine, then ignore my previous comment........