Hard starting 57L EFI Mercruiser

"Just in the past couple of da

"Just in the past couple of days, I have been having difficulty in turning over my starboard 5.7L EFI Merc. From the control console, I'll depress the start button, get the normal beeps and then the engine will (I hope I can relate the sound somewhat), go ugh. I hit the button again and it will ugh,ugh and still not start. I will do it once or twice more and it will finally turnover. I check the battery voltage and its steady at 13 -13.5 amps. Yesterday I replaced the ignition sensor in the distributor, but on the first attempt to start it, it followed the same sequence as above.
This just came out of nowhere, it was working fine all season, up until this past weekend. Any ideas? Where should I start to troubleshoot? Any help would be really appreciated."

Are you getting spark? Enough

Are you getting spark? Enough fuel? Water/fuel seperator filter is loaded up?

"I'm sure I'm getting

"I'm sure I'm getting fuel. I can hear the jets inducing it when I hit the Console start. As for spark, I didn't think to check. And I'll take a look at the fuel/water seperator. Thanks for the info."

"You may need to take another

"You may need to take another stab and describing the condition. Sounds like a starter circuit issue... like it's barely cranking over and eventually it will start. What type of boat?

If my assessment of your situation is correct, you may have battery or battery wire connection issues. Consider switching the starboard and port engine batteries (if they are separate) and see if the issue occurs on the other engine."

Voltage at the battery doesn&#

Voltage at the battery doesn't mean much sometimes.

Try doing a load test or changing the battery with one that is known to be good.
You can also check the voltage while someone tries to start the engine & see if it drops way off.
If you have a Harbor Freight store near by they have load testers for about $20.00.

A draw test on the starter should be done if all is well with the battery.
Also make sure the timing has not changed(loose distributor lock allowed timing to advance).

If all those systems check out there could be a leak from one of the manifolds letting water in a cylinder making the engine hydro lock a little.
If this is the case it should get worse the more you run it until it gets at the point where it will not turn over at all after sitting awhile.

Just a few ideas. It could be other things as well but this is where I'd start.

Check the distributor cap and

Check the distributor cap and rotor for condisation. I just recently had a similiar problem . I thought i had a dead spot in my starter which would have been a headache and it turned out to be a corroaded rotor...good luck.

I have a 76 searay with a 233

I have a 76 searay with a 233 mercruiser engine I think it's like a 302 ford would like to know the timing gear marks. Thanks

Sorry I posted in the wrong pl

Sorry I posted in the wrong place. But I would check the wiring to the battery and starter it sounds like it is just dragging.

"Carl,
I did that. I replace

"Carl,
I did that. I replaced the Ingnition Sensor on Sunday, based on what occured last year with my port engine. The cap was dry as a bone and the rotor was just as good, no rust, no condesation. Did a test tonight and it looks more and more like battery. Why? I don't know, they are all only two years old (really a year and a half usage wise). Tonight, using Emergency Start, the initial time, the baby turned over like no tomorrow. Then re-starting 5 times without Emergency Start, worked just fine. Here, I was sweating starter, then risers, etc. Once it starts, it sounds just beautiful. So, I think it comes to the batteries. What I'm worried about is why? Again, only 1.5 years old. Maybe something on the enegine is draining the battery? Who knows? That's my next investigation. But thanks for your input."

"Don: check the alternator ou

"Don: check the alternator output on each engine for comparison. One may have a weak output or corroded wire connector. Use a digital voltmeter so you can see the actual votage of 14.2 to 14.5 volts output clearly. To check for a bad wire from the alternator to the starter or battery, there should not be more than a 0.1 to 0.2 voltage drop from the alternator output to the other end. If there is, clean both terminals and the connectors and check it again. Still the same? Replace the wire with a fine multi-strand wire of the same gauge. Use shink wrap connectors. Guy"

Maybe you have a MerCathode sy

Maybe you have a MerCathode system that is connected to that start battery and is slowly draining your start battery while you are not using the boat. These are normally wired before the battery isolating switch. Just something to check if your battery is only couple years old.
Cheers Roger