engine overheats at idle

[erikincider]

1986 stingray 2.5 gm aplha 1 outdrive first time in water and it is running very hot.at idle it runs hot , cruising around 2000 rpm it is fine,checked impellar in outdrive not torn new water pump on engine when running at higher rpms it gets hot also

 

[MarkJSullivan]

Re: engine overheats at idle

Before you go and spend a lot of money, test/replace the gauge. These engines are simple enough where a new impeller should have done the trick. We tend to overcomplicate. I just went through a nightmare to find out there was a missing o ring.

 

[erikincider]

Re: engine overheats at idle

i know the guage works i do not feel water flowing through the hoses even with the muffs! i disconnected the hose from the thermostatt housing and water flowed backwards but not upwards to the engine

 

[boatingfool]

Re: engine overheats at idle

How much water is coming out the exhaust??

 

[Northern Eclipse]

Re: engine overheats at idle

You mention you checked the impeller, are you saying you did not change it but just inspected, The impeller may look good but if its been in there awhile it needs to be changed they vanes get weak over time and start to get brittle, then they break I would suggest you put in a complete impeller Kit that includes all seals and housing, they don't cost that much more then just the impeller alone. One other thought, you said you changed water pump on the engine..did you use a marine pump? ..a automotive pump will not cut it different impellers and shaft seal/bearings. One thing to check first is since you did change the pully pump, did you get the belt tight enough??

 

[flashback]

Re: engine overheats at idle

Ericmoneypit, How long have you owned the boat? from your post it seems this is the first time you have put the boat in the water. If this is so, then possibly a privious owner may have changed out a bad impeller and there may be pieces of it in the cooling system. you may need to back flush the system and remove the hoses to make sure everything is clear. In most cases, running hot at idle is a sign of a bad impeller or blockage..... good luck

 

[erikincider]

Re: engine overheats at idle

i bought the impellar kit and will install it saturday the water pump on the engine was given to me with the boat looks like the original one, the belt is tight.before i had it in the water i ran with the muffs and it did not go over 180 but now its not even working with muffs must be blocked like you said since it works when it wants to iam going to change thermostatt while iam at it just in case