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2001 4.3 Mercruiser, Fresh bottom end and head rebuild, Stbd Ex Mani cool, Port gets hot

oxnut85

New member
Had a hydro lock situation, saltwater in all 6, pulled the block, new pistons n polished crank. Put it back together, new t-stat hsg as well, started right up but not smooth like the Stbd engine, but it's like its running fat, only on the port side where the manifold is getting hot, like no water going to the manifold, but, checked the elbow and the pipe is clear, and water is flowing but not sure if it's to full volume, I pinched off the stbd pipe to that manifold and the port side did seem to cool off a bit. Something isnt right, pulled the plugs, stbd side nice and normal, port side, a little carbon (black) and some brownish flat textured discoloration on insulator and bridge. seems like a little salt water is getting in there somehow. The flappers seem to be fine, no stiction there, possibly an obstruction on the way out or low volume in from the skeg (Alpha). Looking for suggestions what to check next. Thanks, Greg
 
Ayuh,..... Is the motor perfectly dead level,..??

Have you replaced the raw water pump impeller,..??

If yer gettin' water in a cylinder, the spark plug will be brand new Clean,....
 
Have you checked the elbows?

Did you find the root cause of the original hydrolock event(s) and eliminate it?
 
The engines are not dead level, pointing up in the front a little, a couple degrees, not excessive by any means, there is a slight list to the stbd side, a couple degrees, not noticeable unless your really looking.
Raw water impeller was replaced in the spring, (not by me, I will speculate it was installed in the correct direction with the locking key). The plugs on the stbd bank look perfect for 3 minutes of on and off run time, the port side, all three had a little carbon (black) and a slightly flat whitish/brownish dry residue. thinking it might be from salt water.
The elbows were the first thing I yanked and it looked like one of the edges between the exh square and one of the water jackets was compromised. by then the salt water froze the rings in the pistons and compression went to crap. I actually put the elbows and manifolds individually in an electrolysis bath and de rusted a bunch of scale in there. I blew all the washing soda and water out so they were not clogged.
Technically, I did not find a smoking gun on the hydrolock situation other than the compromised manifold/elbow gasket, what I couldn't figure out
 
I have all the hoses disconnected from the T-stat Hsg. had the blue plugs out of the lower elbows over night to let them completely drain, put them back in. I blew into the stbd side to see how much resistance there was, then the port side. Weird difference between the two. Stbd side, felt very little resistance before I heard the air gurgling down in the Y Pipe, but, I could hear air escaping from something on top of the engine, I taped a baggie to the top of the carb and blowing into the stbd exhaust water pipe the baggie was filling up and relaxing when I let it release. This should only happen if one of the pistons was at TDC where the ex and Intake valves were at overlap, I turned the crank a pit and the condition didn't change. Blowing into the port side, much more resistance and i was clearly lifting trapped water in the Y pipe before it went Glug, Glug. when I released the pressure clearly the trapped water was pushing back the trapped air. So I am going to pull the top elbows and exhaust components as far down as I can go. Not sure if there is a rag or other obstruction or did an animal crawl in there and die in the spring when the out drives were off. Cant wait to see what's in there. The Stbd side, it's like the valves are open a bit, this is a Vortec, no valve/rocker adj on these you torque them down to 22 Ft-Lbs in a cradle that sets the push rods in the new roller lifters. going to pull the valve covers and loosen the rockers to see if the valves close, really weird. Greg
 
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