Last year, I bought a 1999 Chaparral Signature 27 with a 7.4 MPI B3 powerplant. I absolutely love the boat and was disappointed when I read the posting from the family who had trouble with the brand new Chaparral with the listing problem. <br /><br />Anyways when I bought it, the engine had 93 hours and now has 195 hours. I picked it up from Lake of the Ozarks in Missouri. If you don't know, this is a very warm, brackish, fresh water resevoir. I now use it exclusively in Puget Sound which is chilly salt water. Before the boat went into the salt; I installed a complete fresh water cooling system meaning only the risers, elbows, exhaust system and cooling system components touch salt water. <br /><br />At 150 hours, my "Cool Fuel" cooler started leaking salt water due to corrosion. The OUTPUT flange where the rubber hose connects from the oil cooler had pitted out. When the shop replaced the cooler, they also found one of the fuel lines (fuel pump to filter base) was also weeping fuel on the SS elbow where it connects to the pump due to corrosion. That was replaced and all seemed to be okay.<br /><br />At 195 hours, I developed another salt water leak on the oil cooler on the OUTPUT side. It had corroded just like the fuel cooler. I replaced the oil cooler and decided to look at everything else before it returns to the water. <br /><br />I checked the power steering cooler since it is first in line on the system. Same type of cooler, but no corrosion whatsoever. I also noticed the fuel line was weeping fuel from some pitting on the elbow again. This is the same line that was replaced 45 hours ago! I pulled the Cool Fuel assembly and found the output side of the fuel pump was also corroding. It was not leaking fuel, but had it continued I would have been a sorry mariner soul miles offshore. The 45 hour old fuel cooler also showed some slight corrosion on the hose flanges on both ends. Nothing extreme, just visible. <br /><br />Needless to say, I'm concerned I have a bigger problem that I'd rather not have. I've replaced all the corroded components including the fuel pump. I checked everything with a microscope. The Mercathode system, wiring and zincs were replaced too as a precautionary measure. I haven't had time to launch and play and maybe I don't want to. <br /><br />The only issue I did find is not even part of the cooling system. I found the output wire from the alternator was never tightened to the post. It showed signs of arcing near the post and on the insulation. The alternator was bench tested and found to be good. I traced the output wire and found it had been spliced with a butt connector. The person who spliced it did not put any muscle into it and I disconnected with my fingers. The butt connector splice was not protected with heat shrink wrap with sealant and was found in between the valve cover and manifold. I did not see any signs it had grounded out, but black paint makes it tough to see. I replaced the entire output wire. My batteries charge much faster now and the boat engine seems to run slightly smoother.<br /><br />1999 Mercruiser 7.4 liter MPI, #OL336434 <br /><br />1) Is there anyone with a similiar problem that could offer some insight to this troubling problem? <br />2) Could the alternator wiring been causing the corrosion issue? <br />3) Would it be wise to run ground wires to the parts that have corroded? <br />4) Any ideas on where to look for other possible causes?<br /><br />I look forward to hearing anything, good or bad.<br />Fishnfreak of Tacoma
