Temperature gauge question?

[Coyote23]

Hi, I have a 1988 Johnson V4 90 HP, mounted on a 16' Procraft fish / ski. It does NOT have a temperature gauge and I'm a little worried, what if the water pump goes out on the water? I can't tell if I'm overheating. I do have that stream of water squirting out the bottom of the engine, so I guess I could keep an eye on that.... My questions are:

1. Should I get a temperature gauge?
2. If so, where do I install it, on the cylinder head?
3. And, what temperature should I be running at?
4. Any suggestions on what kind, which guage to get?

Thanks in advance for any input on this!

 

[bob johnson]

Re: Temperature gauge question?

my opinion

ABSOLUETLY

WITHOUT A DOUBT!!

so what if the water is squirting out the tell tale...doesnt that mean the head is cool

HEEELLLL NO

the temp guage tells, WHAT the temperature is....that is GREAT info at all times

you go install a BRAND new water pump...and then the first day you clog it with mud....and 20 minutes later you blow your engine....

the temperature gauge lets you see ...as long as you look at it once in a while


the alarm is there to protect you....if it is equiped and working right....

ill never have a remote control motor without a temp guages in each head again

bob

 

[minuteman62-64]

Re: Temperature gauge question?

RE: where to install in the cylinder head.

I bought one of those HF remote sensing temp.meters and, while running on the muffs, checked various locations on the head where the sensor could be mounted. Picked the location that showed the hottest temp. (over 5 degrees variation over the head surface).

 

[bob johnson]

Re: Temperature gauge question?

where ever you can!!!!!

many have a threaded port, others can be mounted under a bolt on the head, you could also drill and tap a place to mount a temp sender.

just do it!!!!

 

[F_R]

Re: Temperature gauge question?

Go ahead and install a temp gauge. It will give you great peace of mind and false security. 90% of the time, when a water pump "goes out" it is because of sudden impeller failure. And when that happens the result is sudden overheating within seconds. The chances that you will be looking at the gauge are nil to none. The motor should have come equipped with an overheat alarm, which will get your attention. Gotta tell you though I have seen lots of cooked motors where the alarm didn't even sound fast enough. Speaking of experience here.

Your best protection against such misfortune is a regular water pump replacement schedule. Before it "goes out". Yeah, I know you are worried about gradual clogging up with mud or something. Pay attention and watch the tell tale. And install a temp gauge.

 

[emdsapmgr]

Re: Temperature gauge question?

The engine came from the factory with two overheat switches-one in each head. Either will sound the overheat horn in the control box if the head reaches 212 degrees (overheat). If you install a typical temp guage, the actual sender usually installs on one head. That's fine for that head. The problem is that the engine has two thermostats-one for each head. If the stat fails on the (other) head without the temp gauge probe, it will probably not indicate the overheat. You might have more peace of mind if you check (test) the head overheat sensors (or even replace them) so that you know the hot horn will sound it if either head overheats. Just to clairfy-I am a fan of dash temp gauges-run one on all of my engines. It does provide a precise reading of head temps.

 

[Coyote23]

Re: Temperature gauge question?

Thanks everyone, excellent advice. Now, what would one of these overheat alarm / horns look like? I'll look when I get home. I'm guessing it would have an electrical connection or what? How can I test them? Take 'em out and hold a torch to 'em? (excuse my ignorance)
I think I will make sure the alarms work, then install a heat gauge in one head. Any suggestions on what kind, does iboats here sell a good one?

 

[bob johnson]

Re: Temperature gauge question?

I installed a temperature sender in EACH head.... they both have a spot for the sender... and I run two seperate temp guages....

I know the temp of each head at all times...

I have a water pressure guages as well....

this stuff is easy and cheap....

how many posts here deal with blown -overheated motors??? they owners find out when its too late!!!

the alarms are great to have......but personally i want to know when my head is getting hotter than 180...i dont want to wait till the horn sounds...since there are a few things that can affect over heating, it is proactive having the gauges... boating is dynamic....and this stuff is cheap insurance.....use all the tools you can, because they are all cheaper than a rebuild.....and less troublesome for sure!!

I am not sure a 1988 motor has the systems check set up.....it might if you have a newer control....

bob

 

[emdsapmgr]

Re: Temperature gauge question?

You can test the warning horn inside the control box. Disconnect the one of the two cyl head temp switches at the bullet connector about 6" from the sender in the head. (It hides under a rubber sleeve.) Turn the key switch to on, and ground the tan/brown wire on the harness end. The horn should sound. Do this for both wire ends where they connect to the head switches. That will test the horn. The factory service manual has a test for the two senders. Basically boiling them in oil and use a continuity tester to check for continuity at 212 degrees.