Have had a suspicion that the previous raw water cooling problems might have caused a problem with the engine as it started blowing a bit of coolant out the header tank when boosting over 12psi, so friday carried out a pressure test on the cooling system and discovered the cap was venting out coolant at 10psi and not 20 due to slight pitting on cap seating, so lapped the seat nice and smooth and rechecked and it was now holding 20psi, I left the pressure gauge on the cooling system so we could keep an eye on things when out on the water.
launched that eve about 7.30 and ran 3-4 miles before winding in some boost and the pressure started climing right upto 20psi and then vented so had to slow down and let things settle a little ,feeling rahther pi##ed off i ignore the advise of my co-pilot and thrashed the s##t out of it back to falmouth with water blasting out the overflow and launching off the pilot boat,s wake at about 40kn,s .
got back ok and felt a little better
got the boat back to the workshop and set about stripping the motor,saturday evening fitted new gasket and got it all back together,I was starting to doubt weather it was really going to fullfil my aspiration,s, so set a plan for sunday afternoon testing.
The plan was to push the engine further than ever before and to hell with the consequence .so sunday afternoon left falmouth after some pre-checks down to the pandorra inn, cooling system pressure at 10psi engine 80c ,all looks good quick pint and rechecked the levels all ok. Left the pan got her up onto the plane and wound the boost upto 1 bar and nailed it and held it there for 10 minutes without any problems we ran at 53kn on gps and no problems egt 875 coolant 90 rpm 6000 ,stopped for a couple of minutes to catch our breath and nailed it some more,and more.
took her back and and everthing looks good I have had a good check over and dropped the drive oil and lower g/box cover and I,ve still even got a full set of teeth, there is still another 8psi of boost in the engine setup and 75-100c of egt in the bank to get to 7000rpm but not sure about pushing much harder intill later in the season as it might be nice to actually get some time on the water for some fun
I am really relived to find that,s its not a complete dud after all the work i have put in its never going to be a really reliable boat but not many fast boats are but its starting to tick all the right boxes for me .