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1985 E25 ELCOC Outboard: Temp sender? Oil Pressure Sender?

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455hota

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I have a 1985 Evinrude E25ELCOC 25HP outboard. I wish to add a temperature sender, and an oil pressure sender. Can this be done relatively easily to this engine? Is there a threaded port in the cooling system and one in the oil system? Thanks in advance...

... Steve T.
 
Racerone, Thanks for your reply. Yes its a two stroke engine, mixed gas and oil. I should have been clearer, the oil in the lower unit, is just gear oil , not under pressure i assume. I think i just answered my own question!!! No sense to have a gauge if the gear case is not under pressure.
Any thoughts on a water temp sensor, or am i over thinking this one also?
 
I bought a 92 Manitou 20’pontoon back in 2020. This 85 25hp evinrude was on it. The remote control unit is the correct original one off the 85 evinrude.
It has ran well up til last august. Hard to start, idle rough running. I figured fuel system.
So this past winter i rebuilt the carb, fuel pump, the primer solenoid, all new fuel lines.
This spring the test fire went flawless!
I found i was not charging the battery, so i replaced the charge coils and the rectifier/regulator. Now i get a small voltage increase when i get up off idle. I am adding a tach, and a volt meter. And i was thinking why not other gauges, but i now will only do the tach and voltmeter.
What impeller are you speaking of? Water pump impeller?
 
Yes, they are made of synthetic rubber now. Best check and/or change every 5 years max. You bought in 2020, so probably should work on that. Thermostats are often bad as well, but on this motor you have to open up the water jacket on the head, which is not really fun, lots of little bolts and complex gasket to clean off and replace. It might be best to just remove the head for the entire job. Head gaskets can fail on these after 40 years of use. If you have an infrared gun, check operating temp at base of spark plugs. Should be about 150°....maybe even 160° there. Thermostat should regulate the temp at between 140° and 150° at the chamber that it's housed in....top of head. If temp is stable, then you probably don't have to worry about it at this time
 
Thanks for the info! I was planning on rebuilding the water pump/ lower unit gaskets this fall. I just put the boat in my pond yesterday. Yes i use it in my 4 acre pond!! I am handy with tools so removing the head does not scare me. I will plan for this overhaul when i pull the boat this fall.
 
I forgot to mention i do have the IR gun so i will check the temperature as you described. Again thanks for the knowledgeable info!!

... Steve T
 
You can add an aftermarket temp sensor to anything, just google "outboard temperature gauge kit" and be sure to get one that includes the actual sensor. Some of the larger engines actually have a threaded fitting for a temp sensor in the head, many do not, but those kits come with a couple styles of bracket that you put a head bolt through, and you find a spot where the included temp sensor will then be in contact with the block...


These work OK, but not great - mostly you get to see what normal running range is, and if something is going wrong there is some advanced warning. The temperature reading cannot be taken literally.

The other thing which does work potentially a little better, and can be installed in tandem or alone, is a water pressure gauge. They T into the telltale hose and there's just a long small hose that runs up to the dash, which shows pressure. Same deal, many versions, this is just one. May or may not take a trip to a hardware store to get just the right T fitting if what they supply doesn't work for you. But overall really simple and these are generally accurate - you can tell when your water pump is operating perfectly or not after some experience seeing how it works when things are new.


As far as removing the head, removing water jacket. It's a good job to do - you see the cylinder walls, you get to clean anything crusty out of the water jacket, thermostat gets replaced, gaskets all get refreshed. The trouble is even on a freshwater engine, even the head bolts themselves, can sometimes be stuck 20+ years later - it's a total coin toss what engine will have stuck bolts, the only engine that won't is one where someone removed the head occasionally during its life & ideally put something on the threads when re-installing them. Usually, it all comes apart fine but if you break a head bolt it becomes a much bigger job, somewhat of a nightmare at times, where everything has to go just right removing it. So the key is do not break bolts..

The basics are, you use an impact of some sort, ideally not an insanely powerful one (like a 3/8 version) so you can tell a bolt is stuck before you go snapping it off, with a MAP gas torch handy to heat the block with anything that is stubborn at all, and a ratchet handy to feel what's going on - some bolts you might try to turn in a bit, then out, then in, then out etc... If a bolt is stuck, move onto the others, as when most bolts are out the head will develop some play that helps you remove other bolts. When you get most of the bolts out, you can use a rubber mallet to wiggle the head around a bit, and that wiggle room can help get a remaining bolt or two free. In a worst case scenario, a bolt that just will not come loose where I think it's going to break, I will literally drill the head off the bolt, to remove a part, so I can work on removing the stud after, instead of snapping it off potentially at the base. Then you have a stud sticking out you can put vice grips on, you can heat directly around where it's seated, all sorts of options become available (including a stud with no part attached, it can actually be turned in as easily as out to loosen it up)...

Same process for water jacket bolts, but the little water jacket bolts, they tend to come right out - or at least are less problematic than head bolts (shorter threads, much less torque used to seat them at the factory, likely only 7 lbs). If my entire concern was the water jacket area, I'd probably try to leave the head, remove the jacket, and do the job that way. Then if you did, in an absolute worst case scenario, break a water jacket bolt right at the base, the removal of it, doing it just perfectly, is not as critical - depending which bolt, you don't necessarily even need them all :), any damage done is only done to the head (which is a part that's cheap & easy to find a replacement for).
 
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