'95 Yamaha I/O 5.7 overheating

[sickofboatsguy]

I have a '95 VIP boat with a 5.7 yamaha. boat over heats when running on muffs or in the lake. Boat runs at normal operating temp when bypassing the outdrive and running on a garden hose hooked into one of the cooling lines. There are no blockages in the outdrive or any of the cooling lines. Water pump appears to be working fine with a new impeller. Any suggestions?

 

[Mercnoob]

Re: '95 Yamaha I/O 5.7 overheating

did your impeller fail before? You may have debris in the drive or in the hose coming out causing a blockage. you can hook up a vaccume to the hose leading out of the drive and suck any debris out.

 

[sickofboatsguy]

Re: '95 Yamaha I/O 5.7 overheating

Hoses have been flushed and are free of obstructions and the drive was removed, disassembled and re assembled with no obstructions found.

 

[Bondo]

Re: '95 Yamaha I/O 5.7 overheating

Water pump appears to be working fine with a new impeller.

Ayuh,.... How did you determine That,..??

 

[sickofboatsguy]

Re: '95 Yamaha I/O 5.7 overheating

it pumps water. It has to be somewhere between the outdrive and the transom.