Frustrating over heating issue, 96 50hp 2 stroke evinrude

The whole story: The first time we had the boat out after purchase last year, the water pump went out, over heated the motor and left us in the middle of the lake. We had that replaced along with a new heat sensor. We got it out one time after that and it worked alright, just puttering around a little. This year, getting ready for the season I changed the lower unit oil, changed the spark plugs, put the muffs on and flushed the cooling system, which looks to be working perfectly. We took the boat out this weekend and everything was fine, until we started running up the lake, we got about three minutes of run time before we got an hot light and warning horn. Shut down, waited about 15 minutes and it started right back up and we headed to the dock, almost exactly the same amount of time back to the dock and it over heated again. The water pump is fucntioning and gives a good solid stream. Any ideas as to why this is happening? Could the VRO be the problem? Any help would be greatly appreciated.

Thanks,

CDBird

Re: Frustrating over heating issue, 96 50hp 2 stroke evinrude

CD

" the water pump went out, over heated the motor and left us in the middle of the lake. We had that replaced along with a new heat sensor."

Did you replace the thermostat. Are you calling the heat sensor a thermostat? If not that's your next move. Sounds like the thermostat is stuck closed.

Although probably not recommended by all... You can take the thermostat out and run the motor up and down the lake. See if it still overheats. If not you know the answer. If it still overheats you have bigger problems.

I wouldn't think it's a VRO issue. If the VRO failed you would be essentially be dry gassing the motor which will cause permanent not temorary problems.

Re: Frustrating over heating issue, 96 50hp 2 stroke evinrude

The thermostat was replaced. I will look into that and see if that's the problem. I'm afraid it might be other damage somewhere, may just have to have it looked at and see at least what's going on with it.

Re: Frustrating over heating issue, 96 50hp 2 stroke evinrude

who replaced water pump? there is a sleeve/seal for waterpump if it is installed upside down it can fold and cause a restriction,but you will still see a stream from telltail. I had this happen on a used lower unit i bought it was "tested" but testing would show any sign of mis-ijstalled seal. mine ran fine at under1500 rpm. removing t-stat will help,meaning it will run longer before warning sounds. if this is the case then your not moving enough water. cause,water pump bad,crack in water passage or tubing ,restriction in motor,exhaust getting water jacket(this also causes poor running) can be ruled out if runs ok. i'm just tring to help get an idea of your problem. remember when trouble shooting keep notes and remember if a fixdoesn't change anything better or worse then it most likly something else. let us know

Re: Frustrating over heating issue, 96 50hp 2 stroke evinrude

stylesabu said:

who replaced water pump? there is a sleeve/seal for waterpump if it is installed upside down it can fold and cause a restriction,but you will still see a stream from telltail. I had this happen on a used lower unit i bought it was "tested" but testing would show any sign of mis-ijstalled seal. mine ran fine at under1500 rpm. removing t-stat will help,meaning it will run longer before warning sounds. if this is the case then your not moving enough water. cause,water pump bad,crack in water passage or tubing ,restriction in motor,exhaust getting water jacket(this also causes poor running) can be ruled out if runs ok. i'm just tring to help get an idea of your problem. remember when trouble shooting keep notes and remember if a fixdoesn't change anything better or worse then it most likly something else. let us know

Click to expand...

The water pump was replaced by a local mechanic. It runs well until I get the heat alarm, so I will check out the water pump. Since when I first bought the boat I knew absolutely nothing about outboard motors. I've learned quite a bit since then. And now that I think about it, when he replaced it he said something about using a 3 blade impeller but that the old one was five. I will check out the water system completely, impelller and all and see what I can learn. Thanks!

Re: Frustrating over heating issue, 96 50hp 2 stroke evinrude

Minor correction, looked up the water pump kit for my motor and it is a three blade impeller.