heat light, water pump intermitent problem on I/O

[scandiaclay]

Hi-
I have an 1994 Ebbtide boat with Yamaha I/O. When I start it up I it will intermitantly show that water level is low and heat begins to rise. It then begins to work fine once I punch the throttle and plane out. It then works fine until the next time I shut off engine and restart. It then may or may not experience the same problem. This happens about once every 7 times I start the boat. The other 6 times it starts and runs perfectly. I am not sure why pump would not pump water sometimes but not others. And why it would always work perfectly after I open up and plane it out. Any thoughts would be greatly appreciated.

 

[thrasher]

Re: heat light, water pump intermitent problem on I/O

I would guess that you have a worn impellor pump. If it's worn it will not pump very well at idle, but as you raise the engine revs, the pump will turn faster and start pumping better, this will bring the temperature down. I do not know why it works well 6 times out of 7!!

Gary

 

[scandiaclay]

Re: heat light, water pump intermitent problem on I/O

thanks for the reply. However, I had a local mechanic change the impeller. He then took it to the lake and it ran perfectly. So we thought problem was solved. But once I got it on vacation I ran into the problem every now and then. He also checked the pump and blew the hoses. I told him the latest and he is baffled...thus the post here.

 

[Don S]

Re: heat light, water pump intermitent problem on I/O

I it will intermitantly show that water level is low

First off, let me say that I have never seen a Yamaha IO, so my question may mean nothing.
On other types of engines, low water level indicates a low level in the CLOSED Cooling system, has nothing to do with the raw water part.
Do you have a closed cooling system with a heat exchanger with antifreeze in it???? It would also help to know what engine you have.

 

[scandiaclay]

Re: heat light, water pump intermitent problem on I/O

They only made the I/O yamahas a few years. It is a 4.3 ltr V6...starndard cooling just like Volvo and Merc. No closed system. Thanks!