Mercruser Hydro lock

I have a Sanger and its never been easy to start. While trying to start the other day it hesitated and seemed like it was backfireing. This happened several times to the point where the motor would not turn. I took out the plugs and all were wet one of the cylinder water poured out when I removed the plug. The motor would not spin so for giggles I removed the starter and it had jammed up trying to turn over the motor. The folks at the marina said its common to Hydro lock motors yet I've never heard of that occuring.
Questions:
What are typical reasons for this to occur?
Do you think my timing needs adjusted?
Is it difficult to adjust the timing?

Thanks in advance

It might be common, but it's not good. You'll destroy the motor eventually. If that water is caught in there on the compression stroke, you're done, and it wont be minor.

I don't see what timing would do. A blown head gasket was the problem in our boat. I suppose water could also find it's way up the exhaust and enter the cylinder through the exhaust valve...maybe.

bad exhaust manifold, warped head or head gasket, could be the cause. no its not good

Interesting. After turning the motor over and removing the water and taking out and replacing the starter it started and ran well all day. I doubt I damaged anything. My goal to to try to figure out why it happened in the first place and eliminate it from happening in the future

Rusted/corroded exhaust manifold or risers could put water in the cylinders, head gasket, cracked block, corroded block/heads (run in salt for many years without flushing?).

Also if your flappers on exhaust are damaged/broken/missing you could get water rushing in and getting ove the risers when stopping or is takiing waves to the stern, especially if weighted down as your risers are closer to the water line.

First thing to do is pull manifolds and risers, make sure they are not excessively corroded and that they seal good. Also doesn't hurt to do a compression test to check for signs of bad head gasket or other engine problems.

If it ever hydrolocks again and won't turn over you need to pull the plugs and crank it over, it'll spit the water out the plug holes. Then put plugs in and run it again, doesn't hurt to spray some WD40 or two stroke oil in the cylinders and crank engine over to distribute it (avoids corrosion on walls/valves and prevents stuck rings).

I had it happen once. The two factors I attributed it to were:

1. A missing flapper door on the exhaust outlet.

2. When I turned the engine off, it "dieseled" - it kept firing irregularly for a couple of seconds.

It wouldn't turn over after that, and when I checked it out a cylinder had water in it. I don't know why it dieseled, but I figured that plus the missing exhaust flap somehow allowed a water to get sucked in through the exhaust valve.

Yes the missing exhaust flap and a dieseling motor can cause that. Those little rubber flaps are a very important item I believe they are their to protect from water rushing into a motor that runs backwards(Dieseling)

I spoke with the guy at Inland Marine in Antioch, CA regarding hard restarts on my V210 (Year 2000, 350 hours, Black Scorpion engine). He told me the problem was with the gasket between the exhaust elbow and the exhaust manifold. It is not the exhaust manifold to block connection...there are no water passages there. There are water passages between the exhaust manifold...and the elbow, though. When the gasket goes, water leaks from the water side...into the exhaust manifold. From there...it leaks down on top of the exhaust valves...and into the cylinder if a valve is open.

The old style gasket was a metal gasket with fire ring. The new one is thicker, flat, graphite coated, no fire ring. Probably because the old one did not work reliably.

Get the SN# off you motor. Go online to the Mercruiser Parts website and look up the parts. You want the gakset between the elbow, and manifold. If you have a riser (unlikely on a Sanger with no freeboard)...there will be two sets of gaskets....one elbow to riser...and one riser to manifold.

I will be doing this changeout tomorrow on my V210... We will see if that does it...and how the original gaskets look.

(Message edited by kitewake on August 28, 2009)

Brant, I have a similar starting problem at the start of the day on the ramp. After that, I'm good for the day. Never removed the plugs to check but this is something I'm going to look into.

Will you take pictures of your repair & post?

The culprit for the difficult starts ended up being a plugged up air cleaner. there is also a white scotch brite type material wedged into the cowl. Mine was black and nasty. My merc had the tsb with the out of alignment pullys. even though its been shimmed it still chews up belts and leaves tiny black belt shaving all over. the shavings had plugged up the spark arrestor/air filter. I'm embarrassed that I did not check that earlier. I suggest that everyone check there filters! Boat starts right up and even idles a bit faster. The scotch brite part cost a wopping 1.38!