Overheated? Damage?

[Mark42]

While on a lake today I noticed the temp guage was high at about 180 - 190F. I turned off the motor and cursed the alarm for not coming on and noticed that no water was coming out of the tell-tale. I guess turning it off caused a heat surge because when I turned on the ignition a minute later it was up to 200 and the alarm went off as a contant buzz. Waited about 20 minutes and it started up, the temp dropped down to 140, water came out the tell tale, the alarm made a few on-off beeps about 1 second long so I shut it off. Waited another 10 minutes and started it again, water came out the tell tale, the temp was below 120 and it ran at 2500rpm for a few minutes with no alarms. Then I ran 3500 for about 2 minutes with no problems and we left the lake.<br /><br />I think the intake was clogged by lake grasses and that funny jelly green glob stuff. Before it overheated we were idling for about 20 minutes through fairly grassy icky water in no-wake zones. After leaving the grassy water, I brought up the engine speed and we cruised in open clear water at about 12-15mph for 5 minutes before I saw the guage reading hot. <br /><br />Wondering if I have done any damage to the motor or pump by getting hot and having grass/weeds/icky crap clog the intake. I'll have to look for my compression guage and take a reading. Never had this motor overheat before so am nervous about trusting it now.

 

[Mark42]

Re: Overheated? Damage?

I found my compression guage! And my solinoid jumper/starter button too! <br /><br />Woo Hoo! <br /><br />Did a test and got 140 psi on each cylinder. Not sure what the psi should be, but I know that even is a very good indicator. <br /><br />Woo Hoo!<br /><br /><br />Can't find the compression spec in my Evinrude/Johnson manual! <br /><br />Oh.... Can someone help me out with the compression spec for '93 40hp?<br /><br />PS, plugs look good, medium brown color like squishy white bread crust.

 

[Dhadley]

Re: Overheated? Damage?

Thats about what we see. Youre good to go. The compression should be no more than 15 lbs different according to OMC.<br /><br />If it were mine I'd change the head gasket or at least retorque the heads. If you havent done a complete water pump job in a couple of years then this would be a good time. <br /><br />The whole time this was going on, what was your water pressure? (hint - hint)

 

[Mark42]

Re: Overheated? Damage?

Dhadley, I am glad to hear from you!<br /><br />I bought the o/b from a rebuid shop last year. I did the breakin procedure and have probably put less than 30 hours on it total. As part of the rebuild a new water pump is installed so I'm thinking its probably OK. I'll do a head re-torque just to be safe.<br /><br />I wish I knew my water pressure! That is the next guage to go in the dash - and I have just the spot reserved for it. I do know what the pressure on the tell tale is from pressing my thumb over it. It still feels the same as before. It's easy to stop the water but still enough psi to shoot out all over when you try. I think Teleflex lists the pressure for my motor at around 12 psi. <br /><br />BTW the manual says the temp switch closes at 203F so I guess I cought it just before the alarm went off.<br /><br />I also checked the sight tube on the VRO2 pump and I can see oil in it. Why do you think the intermittent no oil alarm sounded then went away after it cooled? Think the heat caused vapor lock in the pump? <br /><br />Thanks for your help.

 

[Dhadley]

Re: Overheated? Damage?

That was the overheat alarm. As the cooling water cooled the sensor down it opened and closed as it cooled off. Nothing unusual. I would agree that the pump is probably OK. Since your reference is the heat gauge, just keep a close eye on it. If you get the gut feeling the pump needs replacing, do it. <br /><br />This is exactly why I like a pressure gauge. The temp gauge tells you what already happened, a pressure gauge tells you whats gonna happen. Your motor should have 20+ lbs at wot.

 

[Mark42]

Re: Overheated? Damage?

Thanks a bunch. I retorqued, ran again and I'm happy.<br /><br />Thanks again.