Mercruiser 5.7L Starter problems...Hydrolock?

[jestncase]

1995 Mercruiser 5.7L Alpha One with 406 hours of use, approx 15 hours of use this season with no problems.

1. Took boat to the lake and it would not start. Thought it might be a dead battery; so another gentleman hooked me up with a jump and the starter would only click and the engine would not turn over. Bad starter I thought.

2. Pulled boat out, took it home and shopped for a new starter. 200 bucks later and with a new WPS Starter, installed new starter and boat starts up in driveway, multiple times with no problems, engine sounds great. I grin with satisfaction knowing that I've repaired something myself.

3. Take boat to lake again the next day after installing the new starter, (yes, I did use all the new hardware that came with the new starter.) Attempted to start the boat and hear a bad noise come from the starter. Pull boat out of water and go home again without a great day on the lake. I grimace with the knowledge that I have to relay the news to my wife that I've not fixed anything and spent 200 bucks for nothing.

4. Pull out new WPS starter and find the nose cone as cracked off the housing of the starter. Go to marine store and demand money back as promised for this WPS starter, after much belly aching, get money back. I grin knowing that I now have my 200 bucks back, yet frown knowing that I still have a problem with starting my boat.

5. For ****s and grins I install "old starter" and boat starts up like she's just off the show room floor. Again, multiple start attempts are very successful in the driveway with the garden hose attached.

5b. I also checked the oil dipstick to find the oil level about 1-2 quarts ABOVE the FULL line, however oil does not appear white.

6. I have not tried to take the boat to the lake since installing the "old" starter.

As I had to go out of town, have not had the opportunity to pull the spark plugs out and check for water in cylinders. My understanding however, is that hydrolocking would not allow the engine to start at all. Is that true? Or would an engine that hydrolocks still be able to start? Engine seems to run fine when it's started, sounds wonderful in the driveway, unfortunately the kids complain when I try to convince them to use their imaginations as I hook up the tube to my wonderfully running driveway boat.

What is going on here? I plan to pull the spark plugs when I get home in a day or two. If it's not hydrolocking do I need to pull the engine and examine the flywheel? Seems that flywheels dont just go bad to me. Am I wrong? Why is there so much oil in the engine? I will drain the oil to a more appropriate level, I assumed the mechanic would have put the proper amount of oil in when he changed the oil at the end of last season. I also checked it at the start of this season and don't believe it was as full as it is now.

 

[TilliamWe]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

Hydrolocked means the motor is locked and won't turn over. It's possible that your cylinder(s) that are getting water in them are somehow draining the water out, letting the engine start later.

Here's a possible thought, that sounds crazy, but might not be:
Your exhaust shutters are gone, and when you back the boat into the water, you are getting water reversion into the exhaust. It won't start, cause it's hydrolocked. After you pull the boat out of the water, and it sits, the water drains past the piston rings and into the crankcase (hence the overfull condition?), allowing it to turn over on the muffs in the driveway later. Crazy sounding, I know, but it's possible, especially with the information at hand.

 

[Blk-n-Blu]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

You need to get the water out ASAP. Drain the oil and replace it and the filter, pull the Spark plugs and spin any water out of the cylinders. replace plugs and run motor for brief periods.

 

[John_S]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

Hydrolocked means the motor is locked and won't turn over. It's possible that your cylinder(s) that are getting water in them are somehow draining the water out, letting the engine start later.

Here's a possible thought, that sounds crazy, but might not be:
Your exhaust shutters are gone, and when you back the boat into the water, you are getting water reversion into the exhaust. It won't start, cause it's hydrolocked. After you pull the boat out of the water, and it sits, the water drains past the piston rings and into the crankcase (hence the overfull condition?), allowing it to turn over on the muffs in the driveway later. Crazy sounding, I know, but it's possible, especially with the information at hand.

Sounds plausible to me.

 

[jestncase]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

You need to get the water out ASAP. Drain the oil and replace it and the filter, pull the Spark plugs and spin any water out of the cylinders. replace plugs and run motor for brief periods.

That I understand, unfortunately, I am a pilot and am out of town until I finish work on Wednesday. Did not think I had hydrolock until I had no time to get water out of engine.

That said, I can change the oil, change the filter, get the plugs and water out of engine but it won't help me fix the problem at hand, the root cause of the possible waterlock still remains to be found if indeed that is the problem.

 

[jestncase]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

Hydrolocked means the motor is locked and won't turn over. It's possible that your cylinder(s) that are getting water in them are somehow draining the water out, letting the engine start later.

Here's a possible thought, that sounds crazy, but might not be:
Your exhaust shutters are gone, and when you back the boat into the water, you are getting water reversion into the exhaust. It won't start, cause it's hydrolocked. After you pull the boat out of the water, and it sits, the water drains past the piston rings and into the crankcase (hence the overfull condition?), allowing it to turn over on the muffs in the driveway later. Crazy sounding, I know, but it's possible, especially with the information at hand.

Where will I find the exhaust flappers? In the elbows or in the manifold or further down the exhaust system?

One other thing to add...both nights prior to launching the boat in the lake, we had two very heavy rainfalls each night when the boat was in the driveway. Boat was covered one night, and not the next. Is it possible that heavy rainfall could be causing my problems even though the engine is covered by a seat? Perhaps water leaking into engine compartment and dripping on electrical components/solenoids of the starter. One last thought is that I just had bad connections on the starter and when I installed, uninstalled, and re-installed the starter I cleaned them enough to "fix" the problem. Although I will be inspecting the exhaust flappers and checking the cylinders for water when I get home.

 

[TilliamWe]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

Of course electrical corrosion could be an issue. But the breaking of the replacement starter leads one to think that there is a physical component to your problem as well.
The exhaust shutters (that's what they are really called, most of the time ) should be located in the top of your exhaust Y-Pipe, where the rubber tube from the exhaust elbow meets it. Some folks are lucky enough to only have to remove the exhaust elbow (no gaskets needed, just hose clamps to loosen) but sometimes you have to remove the exhaust riser also, just because the rubber exhaust hoses are so stiff.

 

[6meter]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

You need to find out if you have a water problem to begin with. Drain your oil first and see if water comes out first. If all oil comes out and no water you could have an electrical connection problem somewhere. The replacement starter nose cone breakage could be just bad luck. Make sure your wires at the ignition switch are tight.

 

[jestncase]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

You need to find out if you have a water problem to begin with. Drain your oil first and see if water comes out first. If all oil comes out and no water you could have an electrical connection problem somewhere. The replacement starter nose cone breakage could be just bad luck. Make sure your wires at the ignition switch are tight.

I drained the oil and it was milky, therefore I am saying there was indeed water in the oil. I measured the amount and there was approx 3/4 to 1 quart of additional water in the oil pan. Now my question is if the engine block was indeed cracked or a head gasket was blown, wouldn't I have much more water inside the engine?

I've run the boat probably 15-20 hours this season and had no problems until last week. The previous week I unintentionally dieseled the engine while stopping. I also had the bad practice of stopping too fast when a skier fell or a tuber became a human meat missle. This practice, combined with my bad launching practice of giving the boat a little extra momentum whilst launching the boat off the trailer leads me and my local mechanic advisor to believe that I've been backing water past the exhaust flappers and causing my problems with starting at the docks and the collection of water in the oil.

I've changed the oil and filter, changed the spark plugs and installed new manifold and heat riser gaskets and checked the operation of the exhaust flappers. If I continue to get water in my oil then I will look for a blown head gasket or intake manifold gasket or perhaps a cracked block. I will be pulling that oil dipstick every ten minutes on the lake tomorrow, provided I can get it started at the docks.

 

[jestncase]

Re: Mercruiser 5.7L Starter problems...Hydrolock?

Of course electrical corrosion could be an issue. But the breaking of the replacement starter leads one to think that there is a physical component to your problem as well.
The exhaust shutters (that's what they are really called, most of the time ) should be located in the top of your exhaust Y-Pipe, where the rubber tube from the exhaust elbow meets it. Some folks are lucky enough to only have to remove the exhaust elbow (no gaskets needed, just hose clamps to loosen) but sometimes you have to remove the exhaust riser also, just because the rubber exhaust hoses are so stiff.

I had to remove the entire heat riser as the rubber was too stiff as you mentioned. Although this provided the opportunity to check the manifold water channels, as well as the exhaust flappers, and I was able to replace the gaskets at a reasonable price. All seemed well, there was a little corrosion inside the water channels, but not enough for me to suspect that they were leaking and the inside exhaust on the manifold did not have any water tracks, just a nice carbon coating that seemed to be uniform. I believe they are servicable for more than a few years with new gaskets.