I hear you backfoot100 and I am investigating options around replacing the manifolds and adding a closed water cooling system. Just compiling a Business Case to submit to the boss for approval!!!! The effects of saltwater don't seem to be as high on her priority list as they are on mine.
I have fixed my sump oil leak am posting the results of the job in case it helps anyone else.
1. I sourced a sump and gasket from my local boat shop. The owner has been in the industry for many years and he knew exactly what I was after. According to him, all the GM 5.7L Evoc based engines have the same core engine block components which include the oil sump. So, he says the same sump is used on Marine Power, Indmar etc. He said it was bad idea to use an old gasket which I knew already from this forum. He indicated that they replace about 15 to 20 sumps a year. Saltwater locations are a lot more accessible here, so maybe that is a factor in this.
2. I pulled the sump off and discovered that the leak was not a hole in the sump, although it was rusted at the bottom, but it was a stripped oil drain plug thread. I think this must have been damaged at some stage and someone tried to fix it with some kind of sealant. This explains the plastic pieces that I saw when removing the oil drain hose.
3. As suggested by the boat shop guy, I sprayed the pan with a galvanizing/zinc paint and installed it using the Marine Power Service Manual instructions on their website.
4. Re-installed the engine. Went through Ron's shaft alignment instructions and discovered all good. Checked for 2 fingers under the pan. All good. I ran the engine and was relieved to see no oil leaks.
5. When I had the engine out, I removed the starter motor. The business end was looking really bad. Rusted shaft and Bendix. The flywheel and teeth were also looking seriously rusted. On a previous Mastercraft I owned with a Mercruiser engine, I had endless trouble with the starter motor, as on that engine, the starter motor was mounted on top from the back, so water picked up by the fly wheel would be sprayed into the front of the starter motor and due to the angle of the engine would flow out through the back of the starter motor. This would result in regular electrics and Bendix replacements. I ended up pulling the engine on that boat and sealing up the dust cover on the bottom of the bell housing to stop water from getting to the flywheel. I had no further starter motor problems after that. The starter motor on my current boat comes in from the front and hence points down so not as bad as the Mercruiser but still getting abused.
6. Based on the above, to save the starter motor, I sealed up the bottom of the dust cover and after putting the engine back, poured just enough oil into the bell housing so that the teeth on the flywheel just touch the oil. My thinking is that this will keep the teeth lubricated and provide just a little bit of lubrication to the Bendix end of the starter motor. Let me know if anyone sees any issues with this solution.
7. I sorted the Auto Bilge so that it works now! Trying to limit the amount of water in the bilge!
8. Ready to ski! Just need to fix my back and knee problems. I wish it was as easy as the boat.
I would like to say a big thanks to RonT and backfoot100 for sharing their valuable experience on this forum. It has been invaluable over the time that I have owned this boat and I know I will always get the correct/real information I need.
Its 100deg F here today, so Summer has definitely arrived and boat is fixed just in time.
