06 4 stroke 25hp water pressure

[bgbass.1]

A friend has a 06 merc. 25hp he says that when he starts it and runs at idle or trolling speed runs great plenty of water out pee hole water pressure good as soon as he hits throttle to go starts loosing water pressure water not coming out of pee hole strong and gets overheat alarm. He has changed thermostat and water pump no help. Also took bottom end down and and removed thermostat ran water from top to bottom he says dosent seem like much water coming out water tube ran water from bottom to top didnt get any water into thermostat housing. checked for obstruction in tube none and he says its building pressure. thanks for the help

 

[Silvertip]

Re: 06 4 stroke 25hp water pressure

Does he have a short shaft motor on a boat that requires a long shaft? If that's the case, when the boat gets on plane the water intake ports come out of the water stream.

 

[bgbass.1]

Re: 06 4 stroke 25hp water pressure

he says that it will even happen sitting still at a fast idle

 

[Don S]

Re: 06 4 stroke 25hp water pressure

With the lower unit off, and after removing the exhaust cover (Plate tstat mounts in) put water to the tube at the bottom and see if you get good flow. If not, time to pull the power head.