TEMP Gauge ISSUE!

[BigwayNZ]

Just wired up the new gauges so that I could finally find out what my Revs are for peace of mind before i send the boat to get stripped down.

Anyway, Tach is great, shows a max ever of 5200 RPM and the speedo bounces between 55-65mph.

The temp gauge is showing readings of right when i turn it on 160 and when idling about 200, when going for it, nearly off the clock.

No overheating horn, i have heard the horn before when nearly out of gas and WOT, it went off. Before i put these in. So when i put this temp gauge in, I just used the same wire sender that was on the last one.

It is obvious that it is wired wrong to me, if it is not then i have a problem i need to address.

Photos, and what each is. Hope they upload in order.

1. This is the wire that is plugged into my temp gauge as 'Sender'. (seems to me to be ground?) IMG-0230

2. what i imagine to be the right wire to be plugged into sender. IMG-0231

3. same thing but other side. IMG 0234

4. where those tan wires go. IMG 0236 and IMG 0235

NEXT POST PHOTOS

5. one tan wire then comes out of the mix?? Where is the other one?

6 where all those joined wires lead to (OMC)

7. Something else that si a mystery to me (maybe off the VRO unit?)



Anyway, if you guys could please help me try and figure this out without having to spend another $500 taking it to the mechanics would be great.

My big questions are, why is the tan wire out of the mix before the plug? I asked the mechanic and he did not know thinking it was off the VRO or something. I pointed it out to him the other day while doing the rectifier, now it looks obvious as to what it is.

Also, where has the other wire gone without having to cut open the tubing of wires to find out?

Is the black one the ground?


is my temp reading the corect temperature? if not, how is it reading at all if that is a ground wire?


Thanks for your time.

 

[BigwayNZ]

Re: TEMP Gauge ISSUE!

number 6 IMG 0232 and IMG 0327
number 7 IMG 0239
number 8 IMG 0233

and the new gauges waiting for a 'new' boat that goes into be restored and painted IMG 0238


If any of you guys know anything about this help would be appreciated.

It is a Johnson 175 hp 2 stroke V6 1988

 

[BigwayNZ]

Re: TEMP Gauge ISSUE!

Might of just figured out my problem.

The temp gauge 120-240F on the teleflex website says it is for I/O and I/B

No idea what inboard/outboard (I/B) is but would this suggest that this was the wrong temp gauge sent to me and would this be why i am getting these readings? Should my gauge just be a cold-hot one?
Would it make a difference seeing the sender is only measuring the heat of the outside of the casing and not the heat of the actual water?

Anyone know if this would be the reason? I mean the water is only luke warm coming out of the tel tale.

P.S. i just realised the black lead is connected to a sender.

 

[emdsapmgr]

Re: TEMP Gauge ISSUE!

From your pictures, it looks like you may be mixing wiring. Pic #1 shows the sender mounted typically on the head. The sender needs to be hard wired direct to the gauge on the dash. Separate wire. You do need to be sure to match the sender with the gauge for correct readings. This system works independently on it's own. You also show other pics of the temp switches on the engine and their factory brown wires. They are on/off switches. There is a switch on each head. When either of these ground out, it completes the circuit and turns on the overheat warning horn in the control box. These don't send a signal, but are tied together and go to ground when the engine head temp goes to 212 degrees. They go to open when the engine gets back down to 175, and the horn silences. You need to be sure to keep the brown wires for this system connected normally and not mix them with the temp gauge wiring/system. The engine should idle about 145-155 degrees in the summer, and may go down somewhat when at planing speeds and the pressure relief valves open. 160 is highish and 200 is considered an overheat. You need to figure out if the engine is really overheating or it is just a wiring issue. Put a laser temp gun on it as a quick check.

 

[BigwayNZ]

Re: TEMP Gauge ISSUE!

This is what I have figured out, would it make sense to you?

Actually, first of all.... The black wire that is mounted on that sender in the first picture... that whire goes all the way to the gauge without interference. So that black lead, connects to another lead (extension lead) and then to the gauge.

That is correct right?


Then i get what you are saying- seperate issue- those factory tan leads, they go into tubing with some other leads such as the ignition leads that plus into the tach (purple, grey and black), however, then there is that photo with a tan lead coming out and not connected to anything at all. That tan lead is coming out of the plastic covering that both the tan leads went into. So how come one is coming out and not going anywhere and the other one is not?


What i think i have done is i have purchased the wrong gague as the one i have is for a inboard by the sounds of it. So the gauge showing the temp is a teleflex 120-240 gauge and i have just conested that to the sender that was already on the motor that was connected to a VDO gauge.

So it would be likely that the sender does not match the new teleflex gauge???


What I need to do is buy a C-H teleflex gauge and the correct sender for it??

I imagine my overheating sign of 200 on the gauge is incorrect cause of the mismatch of the sender and also because that gauge is not for outboards???


So a different issue is these 2 tan leads coming out of each side cylinder... how come one dissapears and is never seen again and the other one dissapears only to be seen again before it goes to that red plug?



So what do you think... is my temp gauge reading so far off because i dont have the correct sender unit? could it be possible that this is why it is reading so high?

Also, should i just buy a new sender or should this gauge work with the correct sender? On the teleflex website it says it 'could' work but on most engines it would show a lower temp than it actually is when running normal. But i imagine that is if you use the correct sender? Can senders really give such terrible readings if they are not correct one? i thought they would all be very similar?


I have only learnt all this since posting this thread and spending hours reading on the net about my problem and that is what i have coe up with, though of course i am looking for opinions on my theory.

Thanks for your reply.

 

[BigwayNZ]

Re: TEMP Gauge ISSUE!

Also, you say the system works independantly on its own..... Does this mean that I should not have the positive and negative leads all connected and joining with the other gauges?

I ahve them all joining together but i have that sender lead on its own hard wired to the gauge and sender.

 

[BigwayNZ]

Re: TEMP Gauge ISSUE!

So at the moment it idles at around 200, then at planing speeds it goes to 240. i am thinking that it is actually reading it backwards because it has the wrong sender unit. Could this be possible?

 

[Silvertip]

Re: TEMP Gauge ISSUE!

Go to the very top of the Electrical forum and look at the generic boat wiring diagram. It illustrates how the instrument panel is wired. As for your temp gauge problem, YES, you do have the wrong gauge. The sender on the engine also has so much corrosion on the connection that it probably is not reading correctlyl. Most temp gauges are calibrated C-N-H but if you look around you can still find gauges calibrated at 60 degrees on the low end and 200 on the high end. This is a far more useful gauge. Here is a picture of one.

Check your PM's.

 

[BigwayNZ]

Re: TEMP Gauge ISSUE!

jUST TO BE ON THE SAFE SIDE, I BETTER DOUBLE CHECK THIS.
hERE IS A IMAGE OF THE WIRING THAT I HAVE DONE. PLEASE EXCUSE THE CHILDISH ATTEMPT AT THIS.

SORRY FOR CAPS.

 

[emdsapmgr]

Re: TEMP Gauge ISSUE!

The brown disconnected brown wire at the red plug may be for the oil tank sender. If the oil gets too low in the tank, it will send a signal to the horn. You should not have any problem using hots and ground from the other gauges for the temp gauge.

 

[BigwayNZ]

Re: TEMP Gauge ISSUE!

So that brown wire could have been for the old VRO unit?

Is that what you are saying?




Also, you say i should not have any problems, does that mean as long as the gauge and sender is matched and it is the correct gauge? it seems my gauge is not meant to measure the outside of the casing but the actual water. my gauge sender is to measure the casing as far as i can tell?

I took it for a spin today and it seems fine, the water is hardly luke warm and steady stream, the casing was hot to touch but not burning hot.

 

[emdsapmgr]

Re: TEMP Gauge ISSUE!

You may want to check the actual service manual for the correct wiring diagram your engine to be sure, but from the ending side of the red plug there is a brown wire to the crank pressure sender, a brown to the three wire plug for the VRO and another leg that also goes to engine ground, and the short one you pictured that may be for the tank. My water pressure sender looks like it is meant to be mounted directly into the water jacket. In fact many (including myself) mount it on a J bracket so that the tip of the sender mounts flush with a solid surface contact with the head. (On later engines, they have an optional cast, tapped socket for the sender to bottom out in.)