1991 Evinrude 90hp VRO temp alarm

[JS4MSU]

I have a 1991 Evinrude 90hp VRO model# E90TLEIE, which gets an over temp alarm after 5-10 mins on water. I can run it at idle in my drive with muffs for as long as I want with no alarm. However, I can tell by touch that the port head is running hotter than the starbord head. Actually the starboard side is coolenough to leave my hand on while running for a long time (in drive @ idle). The port side gets hot within a couple minutes, but is still bearable. I have changed the impeller with no change. Does anyone have a suggestion where to start the next diagnosis?

 

[multimech]

Re: 1991 Evinrude 90hp VRO temp alarm

Sure. Are the thermostats new and not corroded? Are the water dams in good shape or not? Are the heads and block surfaces flat?

The reason you can run it on the hose for as long as you want with no alarm is that you have the hose pressure aiding the waterpump.

 

[JS4MSU]

Re: 1991 Evinrude 90hp VRO temp alarm

I suppose I'll start at the beginning of your list, with the thermostats. From there, I'll have to view a breakdown of where/what the water dams are. Is there a link to find the drawing....while I purchase a service manual?

 

[JS4MSU]

Re: 1991 Evinrude 90hp VRO temp alarm

I suppose I'll start at the beginning of your list, with the thermostats. From there, I'll have to view a breakdown of where/what the water dams are. Is there a link to find the drawing....while I purchase a service manual? Thanks

 

[JS4MSU]

Re: 1991 Evinrude 90hp VRO temp alarm

I bought a thermostat kit to install tomorrow. The ones that I removed don't "look" bad. There's no corrosion, build up, or anything else noticeable. But, I'll replace them just as well. I noticed in the archives that someone had posted a thread on removing the thermostats/housing. I found it very easy to do with a 7/16" crow foot wrench, once I removed the lower cowl (I thought that might help someone else out). I was wondering if it is okay to run the motor with the muffs/garden hose on, and leave the two hoses off that go from the heads to the thermostat housing. I'll admit that I already did that so I could verify even water flow from both heads, and test the water temp. I didn't let it run very long, because I was unsure if I would cause damage (pretty stupid without asking first, huh?) Regardless, the flow appears to be equal, but the port side is a little bit warmer than the starboard side. Any other suggestions based on this so far?

 

[kjdunne]

Re: 1991 Evinrude 90hp VRO temp alarm

"the port side is a little bit warmer" is not unusual if you mean 5 or maybe 10 degrees difference and you have good flow. Flush the outlet side of the of the water passages to eliminate any blockage. See what happens with the new stats, you may be OK. Best to check temp with a contact or infrared thermometer. If you still have trouble, probably need to check water diverters (dams)and water jackets at the cylinder heads. Get the factory manual for your model, aftermarket ones aren't worth it.

 

[JS4MSU]

Re: 1991 Evinrude 90hp VRO temp alarm

Ok, the thermostats are done. Everything is put back together. Started in driveway with garden hose/muffs. After a couple minutes I have an alarm every other second now! I read that this is a problem with the VRO oil supply or pump. I didn't have this before...only the constant beep of overheating. The oil tank is 1/2 full. What do I do now?

 

[kjdunne]

Re: 1991 Evinrude 90hp VRO temp alarm

That alarm is the VRO pump thinking it has no oil supply. Try pumping the oil line bulb to make sure oil is getting to the pump. Check oil line for air leaks, kinks, or any other restriction. Run 50:1 premix until you are sure the VRO is working.

 

[JS4MSU]

Re: 1991 Evinrude 90hp VRO temp alarm

I started the motor up,and there was no alarm. I figured this is normal because it had about 1.5 hours to cool and settle down since I turned it off when I heard the intermittent alarm. I didn't want to wait for the alarm again, so I pumped the oil bulb several times while the engine idled. I let it run for 10 minutes with no alarms at all. I didn't try switching gas tanks to a 50:1 mix, because I thought I should verify if the oil bulb pumping would work first. It seems like it did the trick. Is it possible to inject too much oil by pumping the bulb too many times? It seems that there is a thin milky residue inside the prop hub, from the exhaust. It resembles what you would get when oil & water mix. I just wanted to add a side note for reference; the compression on port side is 110, 110...the starboard side is 120,120. Is there anything else I could or should do before heading out? I think I'm ready to put it in the water tomorrow for a test run.

 

[kjdunne]

Re: 1991 Evinrude 90hp VRO temp alarm

I'd recommend running premix until you verify the VRO is pumping oil, the only way to be sure is to see the oil lelel in the tank drop after running for quite a while. Remember, the engine only uses about 1 gal. of oil for 50 gals. of gas, so it takes some running to see oil level drop. Mark the tank level with tape and go for a cruise. The extra oil from the premix won't hurt anything, not enough oil will hurt a lot!
I don't think pumping the bulb will force too much oil thru the pump, but I'm not really sure. Some oily residue in the prop is normal, usually it's dark, almost black. Gray might indicate too much oil, or gearcase seal leak. Does it smell like gear oil, or just burnt oil? Clean the hub and see what it looks like after running for an hour or 2, after you aren't running premix.
Your compression #s look OK, add some SeaFoam to your gas to help clean up the cylinders and recheck compression after 5 - 10 hours of running, they may even out some or come up, but they look OK as is.

 

[JS4MSU]

Re: 1991 Evinrude 90hp VRO temp alarm

Ok, thanks for the help/input. I'll take her out for a ride in a little bit. I'll run pre mix until I verify the oil tank level drops. I appreciate the thorough response.