Question re: Mercruiser 454

[paulrfrancisco]

This weekend I fired up the engines on my 30' Cruisers. They are 300hp 7.4L 454ci FWC MercCruisers. I really have 2 questions. 1. On the first engine, after the fogging oil burned off, the engine continued to emit a white smoke. I ran the engine about 10 minutes, enough to bring it up to tempature. There was a hint of antifreeze smell that seemed to come from the smoke. Is there a way to determine if there is a problem where antifreeze is "burning" in the cylinders or could this be indicative of another problem, like risers maybe, however since it is FWC, I dont think its the risers.<br />Engine sounded great aside from the smoke and smell...<br /><br />Second question is on the other engine. When I started it up, there was a whistle/whine sort of like a turbo charger sound coming from the engine. Last year this engine did not do this when I winterized it. The engine sounds pretty good otherwise and also doesn't emit white smoke or smell of antifreeze... This engine is the one that drives the power steering pump, but the sound doesnt seem to be coming from that... any thoughts from experience out there? ps... This engine/drive also has a leaky Outdrive Lube resovour and it had emptied out over the winter and the alarm was going off...could low lube levels cause this whine.. The leak appears to be at the bottle/hose union, not in the drive itself, so I assume the drive was not "dry".<br /><br />Paul

 

[SeattleMatt]

Re: Question re: Mercruiser 454

The first engine sounds like the possibility of a blown head gasket, two easy ways to check this:<br /><br />1. Test the compression with a compression tester.<br />2. Buy a kit that you put dip in your coolant to determine if it has hydrocarbons from fuel and exhaust entering into the coolant.<br /><br />You can also find out after some running the coolant level will most likely drop since it's burning it.<br /><br />Second engine, i'm not sure if there are any vacum hoses on your engine but if there are I would check them for leaks. could also be a whining bearing somewhere, I use a stethascope for finding bearings like this.