Engine temp

[elwilliams13]

My 1991 evinrude 225 has the thermostats removed by previous owner. Today when I ran it on the flushing adapter I noticed the port side cylinder head was hot to the touch and the starboard side one was significantly cooler. When I run the engine at sea it reads at 175 degrees although the sensor is on the starboard side head. What to do here?

 

[rodbolt]

Re: Engine temp

hello<br /> it may be time to remove the heads. with the t-stats out you have no water pressure control<br /> does the motor still have the water control valve on the stbd side of the block or has it been updated?<br /> you need to get the correct parts in place then recheck it. that is why I like a pressure gauge over a temp gauge. I have seen to many v motors melt the bank that does not have a temp sender. <br /><br /> good luck and keep posting

 

[clanton]

Re: Engine temp

The 1991 225 has a temp sensor for each head that is connected to the orignal warning alarm system.

 

[elwilliams13]

Re: Engine temp

I see the two wires you are talking about for the senders. I also have that vlve thing on the port side it is not hooked up either. Will it be advisable to put in new tstats. I have been running it for some time with no problems.

 

[elwilliams13]

Re: Engine temp

correction from the last post. The water control valve is on the starboard side but no hoses connected to it. How will I be able to test the original engine temp warning system. I also mhave a pressure gauge. It reads at about 8 psi at 5000 rpm. The tell tale is working fine.

 

[Solittle]

Re: Engine temp

1. You can test the temp senders by grounding the tan wire. Temp should be in the range of 145-165 I think.<br /><br />2. Not good to run these engine without t-stats.<br /><br />3. The water pressure reading to both of my guages at idle is 8-10 lbs and 20 lbs at WOT. Time for you to replace the water pump.

 

[rodbolt]

Re: Engine temp

hello<br /> with no hoses going to your water control valve either some one has been working on the powerhead that is clueless. or the update thermostat kit has been installed. I would have to see a picture to tell you. if you were more familiar with it I would describe it but my typing skills are lacking . those looper motore did not like to run with cold heads. causes a lot of carbon/unburned fuel problems and they usually dont idle well. the thermostats are also part of the water pressure control system. no t stats no water pressure. now you have to remove the thermostat coves and see what was done. if the update was done then replace the vernatherm looking things that pass for tstats now and do a pump kit. if someone just decided that it did not need all the extra parts and removed them you have to go get them and reinstall them. maybe Joe Reeves can help with some part numbers that will be on the tstat covers if the stats were updated to the valvlesss type.<br /> good luck and keep posting

 

[elwilliams13]

Re: Engine temp

I pulled the tstat covers and there was a plastic thing that screws onto a diaphragm. What is the routing for that water control valve? It had an oil cooler on it from the power steering it had from omc. What to do next?

 

[BillP]

Re: Engine temp

If you are running without a tstat I'd suggest decarbing often. Otherwise, like posted above, you will likely have big time crud buildup on the piston crowns and rings. Next will be a hole in the top of a piston from this stuff holding heat or a stuck/broken ring. Does it have a rough idle?

 

[seahorse5]

Re: Engine temp

How your cooling system is supposed to work is that the water control valve directs water pressure to the back of the diaphragms pushing the plastic encapsulated thermostats onto their seats to regulate engine temperature. That also builds up water pressure in the cylinder block at idle. As the throttle is advanced, the valve directs the water overboard, lessening the pressure against the diaphragms and allowing the thermostats to come away from their seats. That way water bypasses the thermostat at higher power settings.<br /><br />Get a parts book or see a dealer and order the hoses that are needed.

 

[elwilliams13]

Re: Engine temp

As I said earlier it runs good and idles fine. It constantly runs at 175 degrees according to the temp gauge. When I removed the thermostat covers I did not see anything that would resemble an automotive type thermostat.If it did not have tstats or somekind of temp regulation system would it still take a few minutes for water to shoot from the telltale? I think what I have is that vernatherm thing stated earlier. It is a plastic piece that looks like a plug of sorts and looks like it would act to restrict the passage making for more water pressure. Also any help with the water control valve is appreciated, can it be bypassed? I have the manual for this engine btw.

 

[elwilliams13]

Re: Engine temp

Hey rodbolt got a picture of what I found when I pulled the tstat cover. Can I email it to you.

 

[rodbolt]

Re: Engine temp

Hello<br /> sure email it to rodbolt40@yahoo.com. I am off to colington to put a starter on one and pick two more broke ones up. Ill get back on later tonight

 

[elwilliams13]

Re: Engine temp

Reattached the water control valve will run it tomorrow and see how it works.