posted 07-02-2003 07:53 PM ET (US)        

So this thread is about cooling and here is the deal:

First of all I have determined that my motor is a 1991 Evinrude E225PXEN (not a 1992, as I had thought). I have and am working from an OMC service manual that covers, "90 degree LOOP V MODELS 120 thru 140, 185 thru 225, 250, 300". With the help of those friendly and capable folks I mentioned above, I have determined that my thermostats need replacing, and I have them (actually the vernatherms) ordered.

But here is the rub.

My manual clearly illustrates the thermostat condition for V4's as one thing and the thermostat condition for V6's as something different. V4's have a simple cover over the thermostat and the thermostat/vernatherm seats against a seal that looks like a bearing seal in the block, and is held in place by a spring that compresses when the simple cover is bolted onto the head. That's all there is to that on V4's in the manual.

V6's on the other hand (in the manual), have thermostat covers similar to the covers on the V4's, with the exception that the covers have fittings for external water hoses to be attached. The port cap has one fitting and a water hose runs from there to a similar fitting on the starboard tstat cover; the starboard tstat cover also has a second fitting and a hose runs from there to a water control valve. Additionally the manual indicates a diaphragm under the tstat cover on V6's, that the thermostat seats into.

My V6 is configured like the V4's in the manual though, with no water hose fittings on the tstat covers, no diaphragms and the water hose that *would* go from the water control valve to the starboard diaphragm, is tied off short of the tstat with a plug in it.

SO HERE FINALLY IS MY QUESTION: Should I acquire the apparently "correct" tstat covers and diaphragms along with my new vernatherms, and route water hoses between the tstats and the water control valve, as my manual indicates V6's to be set up? Or did either the factory or someone else after the fact change this out for a good reason and I should therefore leave it alone??

Thanks-

posted 07-09-2003 08:37 AM ET (US)            

LHG, I guess I could have been clearer in my question, but the possible scenario you described is exactly my concern. I have never paid any attention to the physical temperature of the motor until this recent spate of problems, and I certainly never was familiar with the difference between the V4 set up and the V6 setup. Actually I don't even know what the overall effect of the motor running in a constant partially overheated condition (if that's what has been happening) might be, but it doesn't seem like it would be good.

The new vernatherms came in and I tested them, finding that they both "stretched out" at just above 140 degrees, as they are supposed to. I installed them in the thermostat housings and carefully installed those in the heads *exactly* as per the V4 diagrams. I've only run the motor since then on muffs in the driveway, and idling for 1/2 hour doesn't seem to open them up, but both heads become very hot to the touch. I may be over sensitive to the temperature of the heads; they seem very hot (I can't leave my hand on them for more than a few seconds), but a temperature probe from one of my testing meters only shows a surface temperature at the thermostat housing of about 125 degrees. I don't know if that's within intended limits or not, but I guess it could be.

Anyway, the search is on for an OMC tech to confirm whether I should be changing the thermostats over (or change them back!) to look and act like those in the manual.

posted 07-15-2003 11:04 PM ET (US)            

The scheme as shown in my manual for V6 Loopers (hose fittings on the thermostat covers, diaphragms inside the covers, and the starboard thermostat has a water hose that runs to the water control valve) is how they leave the factory and how they remain *unless* someone calls and complains that the motor won't idle well. There are no service bulletins dealing with the issue, but on an informal basis the factory has given instructions to individuals to remove all the stuff I mentioned and just use the simple covers with no hose fittings and no diaphragms, just like the V4's, because the OEM configuration cools too well at idle causing the roughness.

So the guy I bought my Outrage 22 from must have complained about rough idle, and he or his marina switched out the thermostats to the V4 configuration so the engine would run warmer at idle, and consequently smoother.