Adding a temp gauge to Evinrude 70hp

[onehunglow]

I have a 1987 Evinrude 70hp with a standard Temperature SWITCH. I had a strange horn problem last year (where the warning horn goes off steady even right after starting the engine yet nothing seems wrong - water, heat, oil, etc - turns out a faulty oil pickup sensor). I want to install a temperature gauge so that I can see whats going on in case something like that happens again.<br /><br />I see mixed information on this - Teleflex says you can either screw in a sensor or mount it on a Z-bracket. <br /><br />Is one method better than the other? I don't want to replace the switch since it will alarm if I am not watching the gauage. If I install with Z bracket, I assume I have to use a head bolt <br />(Uggggggh - the thought of undoing a head bolt in a perfectly good running engine scares me) - and then doesn't it have to be re-torqued back?)

 

[DHPMARINE]

Re: Adding a temp gauge to Evinrude 70hp

Have you thought about a water pressure guage?<br />The temp guage will tell you when you are TOO hot.<br />The pressure gauge will warn you as your waterpump wears out.<br />DHP

 

[RRRKKK]

Re: Adding a temp gauge to Evinrude 70hp

I too had never thought about a pressure gauge. I know a long time ago Richard Petty installed one in his race car, as when the water is gone the temp gauge will read normal as it won't read steam. How do you install a pressure gauge my motor is a 1991 60hp 3 cyl?

 

[Hooty]

Re: Adding a temp gauge to Evinrude 70hp

Your OMC dealer should have a kit. They usually tee into the line with the tattletale.<br /><br />c/6<br />Hooty

 

[dajohnson53]

Re: Adding a temp gauge to Evinrude 70hp

The teleflex pressure gauge kit is pretty easy as well. Installation instructions are on line so you can give it a look and decide if it looks straight forward for your rig - before you buy.

 

[onehunglow]

Re: Adding a temp gauge to Evinrude 70hp

Yes I have ordered a water pressure gauge - The installation looks pretty easy - A T-tap into the water hose - what could be simpler? <br /><br />But as for the temparature gauge, has anyone installed one using a bracket? Has anyone unsrewed a head bolt for this purpose?

 

[stairliftoheaven]

Re: Adding a temp gauge to Evinrude 70hp

can someone clarify where a water pressure gauge connects to? and what exactly is the gauge measuring? i assume the pressure of water in the water jacket around the engine><br />regards<br />chris

 

[codkiller]

Re: Adding a temp gauge to Evinrude 70hp

onehunglow,<br /><br />I have been using the temp gauge that you talked about with the sensor installed on a "Z" bracket which is installed on the head via a head bolt on a 1990 200hp Evinrude. I had the old style temp gauge which was color coded and have since changed to a gauge that reads 120 to 260 degrees. The gauge setup works great, motor runs 140 - 160 degrees depending on rpm. I have also just added a water pressure gauge which I will be able to check out on the water tomorrow. In the driveway on the muffs I get 8 psi at idle and about 12 psi at 2000 rmp. I think the combination of both a temp and water pressure gauge is a good idea. Someone on this forum said it all with the following:<br /><br />A temp gauge tells you something is wrong after its happens.<br />A water pressure gauge tells you something is wrong before it happens.

 

[Lowranger]

Re: Adding a temp gauge to Evinrude 70hp

Hooty, My '89 Johnson 70 has "Tech Series" gauges already installed so I'd like to stay with that original OMC style. Are they still available? Is the OMC gauge also tee'd in to the tell-tale just like the Teleflex ones? Is the pressure converted to an electrical signal and "sent" to the gauge by wire or is there a small hose that exerts pressure to the gauge? Thanks

 

[Hooty]

Re: Adding a temp gauge to Evinrude 70hp

The OMC style should still be available. It's a small hose that tee's into the tell-tale and goes to the pressure gauge. The pressures that codkiller's getting are right in line. Max pressure at wfo is gonna be in the 18-20psi range.<br /><br />c/6<br />Hooty

 

[Lowranger]

Re: Adding a temp gauge to Evinrude 70hp

Hooty, Thank you very much for your prompt, courteous reply. This web-site is awesome.

 

[Basstactics]

Re: Adding a temp gauge to Evinrude 70hp

I also added a Teleflex water pressure gauge on my 65hp Johnson. I couldn't get it to read when T'd into the telltale hose unless you spiked the gauge by plugging the telltale outlet. I ended up replacing a plug in the water jaceket with a nipple and running the hose from there. Works great now.

 

[Hooty]

Re: Adding a temp gauge to Evinrude 70hp

I think the OMC kit has a small orfice, for the tattletale which acts as a restricter. Without it the gauge won't show pressure.<br /><br />c/6<br />Hooty

 

[Lowranger]

Re: Adding a temp gauge to Evinrude 70hp

Hooty, My Johnson tech. relocated the tell-tale discharge hose from the port side of the motor to the top, as per O.M.C.'s service bulletin. Trapped air in cooling system, as I recall. He also removed the restrictor nipple at the pan as instructed. If I read your last post correctly, I'll re-install this restrictor to allow the pressure gauge to function properly. Is this in conflict with the Service Bulletin's directive and will this adversely affect my cooling system performance? Pete

 

[Hooty]

Re: Adding a temp gauge to Evinrude 70hp

Hmmm. I understand moving the discharge hose. Was it moved to the top of nr. 1 cylinder? That's where the air pocket formed. It's the highest point in the cooling system. Try it without the restrictor but I'll bet it has to be in there for the gauge to work properly.<br /><br />c/6<br />Hooty

 

[Lowranger]

Re: Adding a temp gauge to Evinrude 70hp

Hi Hooty, Yes, it was moved to the top of nr.1. Then, a new length of hose was ran down to the pan. With the restrictor removed, the hose was threaded through the hole and secured with a zip tie. http://www.c-brats.com/albums/Adeline/discharge_hose.thumb.jpg Pete

 

[codkiller]

Re: Adding a temp gauge to Evinrude 70hp

On my 200 I came off the pressure side of the water control valve ( the 90 degree elbow coming from the adapter going to the water control valve ). I finally got the boat on the water this weekend I get 20 psi at 3500 around 30 psi at WOT.

 

[onehunglow]

Re: Adding a temp gauge to Evinrude 70hp

Hey stairliftoheaven, to answer your question regarding the water pressure gauge, the idea is to measure the water pressure coming out of the motor (that thin stream you see when your engine is running)<br /><br />There are 2 main reasons that your water pressure can drop or fail 1) you have a restriction is the water instake (ie you picked up a plastic bag or seaweed that is sucked against the holes and restricting water coming in) or 2) your water pump has failed or is failing.<br /><br />As these wise boat users have stated on this forum , it is probably more prudent to monitor the water pressure over the temp since the temp will react AFTER any problems have caused the cylinder head to overheat (and the once the temp rises, it goes up fast)<br /><br />The water pressure is simply measured from the stream output however I see mention of "tattletale" which I still don't understand.

 

[jtexas]

Re: Adding a temp gauge to Evinrude 70hp

Hey Hooty, isn't the only purpose of the telltale to let you know that your water pump's working? Then once you install the gauge, why do you need it? I mean, why T into it instead of just terminating the line at the pressure sensor?<br /><br />this is good info - thanks,<br />jtw

 

[onehunglow]

Re: Adding a temp gauge to Evinrude 70hp

Sorry to sound like such a "newbie", but what is the "telltale"? Is it not the same as the pisser?