Descaling my 1989 GT150

[1989GT150V6]

Hi

I recently sprang a small water leak from the seal/gasket between the top plate that channels the water across the top of the Starboard head so ordered a new gasket and replaced.

When I took the plate off I noticed a lot of scale build up in the channels so sprayed it with a 50:50 solution of kettle descaler and water to remove the deposits.

This worked well and once rinsed with plenty of fresh water left the channels pretty clean.

When I started her up to test the seal I noticed several large lumps of scale came out of the exhaust through the prop and the water flow exiting seems to be better.

I guess that some of my descaling solution entered the power head via the channel behind where the thermostat sits and has dislodged some of the scale build up that was then flushed out when running.

So this makes me wonder - is it a good idea to carry out some additional descaling to clean out the water system? Looks like the channels haven't be cleaned out in 27 years so it could do with doing but don't want to damage the engine.

If it could be done has anyone done it and if so how?

Could just spray descaling solution into the top ports and leave for 1/2 HR then flush with muffs on a running engine.

Any help or advice gratefully received.

 

[johnnygjr]

Place engine in a 55 gallon drum rather then muffs. Use a desalting agent in the solution. Keep a running hose in drum to keep temperature cool.Make sure stats. are opening up. Water flow out of telltale should be warm not hot. Should be able to keep hand in water stream indefinitely if motor is running up to par

 

[1989GT150V6]

Place engine in a 55 gallon drum rather then muffs. Use a desalting agent in the solution. Keep a running hose in drum to keep temperature cool.Make sure stats. are opening up. Water flow out of telltale should be warm not hot. Should be able to keep hand in water stream indefinitely if motor is running up to par

Thanks Johnny, will do.