3hp mercury pumps water until it warms up.

[Lostfisher]

I have a 3 hp mercury. It is a 2003 i just changed the impellar and it pumps water great until the motor starts to warm up. than it is steam out of the pea hole. I am running j4c's.

 

[Lostfisher]

Re: 3hp mercury pumps water until it warms up.

I think it is just my tanks It can idle all day but when i throw it in gear the water slowly stops peeing

 

[Sunfish12]

Re: 3hp mercury pumps water until it warms up.

My 5hp Yamaha had the same symptoms. Impeller was changed so I pulled the exaust cover. It was full of corrosion and 2 water ports were clogged. I poked through with a coat hanger and now runs great. This is just one possibility. You should check the compression first to make sure nothings going on there.