Merc 5.0L 220hp V8 won't start

[wgalmond]

I will start out and say that I still consider myself fairly a novice (owned boat 3 yrs) About a week and a half ago, took my Maxum 2400SCR for a cruise. Started slow, but started nonetheless. Almost sounded like it was weak batteries, but the boat has been on shore power for a few weeks and batt's were fully charged. Was out for about an hour or 2 and stop and started a few times. Started slow still. Came in for the day, and then went back to the boat the next day. Could not get the boat started again. Upon several suggestions, I did the following:
1) Had batteries tested at West Marine, they stated 100% health, 100% charge. I bought them in July 2011. What is typical life expectancy on marine batteries?
2) Changed spark plugs....looked a little fouled, but not sure if it was due to constantly trying to start boat.
3) Changed, plug wires. (something I had been wanting to do anyway.
4) Coil wire was difficult to get off. When I did it looked like crap inside the connector. Looked like diaelctric grease, more than likely from previous owner.

Still no start after all this, so I looked further.
Coil cylinder itself was all rusted on the outside and probably the original (2000) so I decided to get a new one give that a shot. Changed that out and then cranked up the boat...after about 3-5 seconds the boat started right up. Let it run to about 170 degrees and killed it. Started right up immediately. I did this several times over the course of a few hours, while I cleaned up other things on boat.

Went back to the boat today, started up and then died about 15 seconds later. And now it will not start at all again. I am at a loss. Any suggestions that I can try? I also had the carb removed at the beginning of the season and cleaned out etc. and put it back on. Someone suggested that perhaps the fuel air mixture settings on the carb are not correct and should have them checked out?

Any feedback is greatly appreciated!

[jrsick]

Good job on thinking this through so far. You changed distributor cap, did you change the distributor rotor also? How fresh is the gas? Symptoms also sound like possibly a camshaft position sensor problem.

[CountryME]

Welcome to the forum wgalmond. Sounds like you are a handy guy and have been hard at work on this issue so far. Just to clarify, it appears that you're working with a 2000 2400SCR with a carbed 5.0 v-8. So you have 3 things that make any engine work: Spark, fuel/air mix, and compression. You have been working on one aspect and considering the other. Since the motor started and ran right after working on the ignition, we can assume it has compression and spark. But due to all the different cut out and kill switches, you should start by pulling a plug wire and verifying that you have good strong spark. After that fuel becomes the question. When was the last time you changed the fuel filter? This is the filter and water separator. Just a little water that gets to the carb can cause a no start condition. Once you have verified a good fuel source, then move onto the carb.

Good Luck and let us know how you made out.

-JP

[wgalmond]

Thanks JP. Yes my boat is exactly as you describe. I have heard and read to test for spark but how exactly do I do that. Would I pull the wire from the distro cap or off the plug side? Then what do I do? Also I changed the fuel water separator In June when I was getting it ready for summer. I am going to the boat in a little while so I was going to look at that as well.

When I removed it before of course there was liquid. I assume a mix if water And fuel hence then name. Can I just take it off an empty it out or would you suggest replacing it again perhaps ?

Thanks for the suggestions.

[wgalmond]

Yes I also changed the rotor as well when I did the wires and plugs. I forgot to mention that here. How would I go about troubleshooting the camshaft issue you speak of.

[CountryME]

Sorry for the late response. I would actually be concerned if you found your fuel filter half full of water, leads me to believe you have some water in the fuel tank. Do not reuse your fuel filter, get a new one and dump a bottle or 2 of dry gas into your tank to eliminate the water.

The cheapest way to check spark is pull one of the plug wires off a plug and using a spare or old plug, attach the wire and ground the electrode end to the engine block by having it sit on something metal. Now, before you turn over the motor, ensure the blower has run a minimum of 5 minutes and the engine compartment is open ( don't want to ignite any gas fumes with theopen spark you are about to create) and lastly don't hold onto the plug wire you will get a shock. Watch the plug for spark while the motor turns over. The other way is to buy in inline spark tester at a local auto parts place.

Good luck and keep us posted.

-JP

[wgalmond]

Hi JP,

Thanks again for the suggestions. I got her running...with the help of a friend who assisted with troubleshooting. He is an auto mechanic who also has experience in marine engines. Came down to the boat this AM to take a look..initially thinking it may be something with the carb. Began to start with a few sprays of ether into the carb. Moved on from there and checked the fuel/water separator from which i changed yesterday. He immediately noticed that there was not as much fuel in it as he would have thought....Then moved to the anti siphon value. Bone dry! This led him to think it was an issue with the fuel pump and/or anti siphon value. He had a 95% degree of confidence that it was the fuel pump.

I went to the marine store that I typically purchase parts from. Lucky for me they were closed! So I went across the street to an Ace Hardware/Marine store. Got the pricing on a fuel pump, and the guy would be able to do it for about $240.00. I was ready to pull the trigger, when I asked about the anti siphon value. He handed that to me, and asked how old the boat was. I said 12 years. Then he asked if I ever changed the fuel lines...I said no. He advised me for a quick cheap potential fix, change the lines ($9.00) and the value ($12.00) Then if it doesn't start, at least they are new. He said that the ether in the fuel does a number on hoses etc and it could be all eroded on the inside etc.

Low and behold, I go to my boat...change out the hose and value in about 10 mins....turn it over and whaammmy! She started right up. Let it idle to about 170 degrees. Shut off the engine...and started it again immediately. Did this a few times and started with ease each time. Left the marina...came back a few hours later, and started up again with ease! Talked to my friend who came down in the AM to look at it, and he said it was more than likely the value that was causing the issue. The hose could have been as well, so it was good I changed both.

Now she's running well, just in time to pull her out But it was a necessity to get it winterized. All set!

Thanks for all the suggestions. I definitely learned a bunch this week as troubleshooting and making my way around the engine, after having replaced a bunch of things....Normal maintenance items, so it's all good!

[CountryME]

Thanks for the follow up. So glad you got her running. Hopefully your troubleshooting story will help some others here on the form. I didn't even give the anti siphon valve, but it makes perfect sense in hind sight.