Both, neither, or one.....

[1flcheesehead]

I have a 2001 Wellcraft Martinique with twin Mercuiser V6s. Engines have always performed well and my last tune up was about 60 hours ago. 3 weeks ago I took the wife, kids and neighbors on a sunset cruise. Both engines fire right up, and we motor out to watch the sunset. Once we get there I shut them down as normal.

When we want to leave, I fire both engines up. They each start fine but within 30 seconds they both stall out. From that point on I cannot get them started. They turn over, sputter, then die.

I got towed in. The next morning I come out and both engines fire right up (sigh). I let them run until they are warm and shut them down. Wait a while, and try again. They run just fine. I do this for a few weeks in a row (at my dock) and there is never an issue.

Today we take her out to the island. Both engines run just fine. We cruise out at about 3k rpms. Once i come off plane the port engine sputters then dies.

She will not start back up. We anchor hang out, then go home on one engine. On the way home I start up the generator and it runs just fine.

Once home i take off the flame arrestors and dump in some seafoam. I am then able to get the port engine running but now the starboard wont start.

I am frustrated and decided to go for help and drink a beer.

Any thoughts on this one? I have EFI and once the engines run they run great. Also, the generator seems to not have any problem.

Thanks for any help you can provide!

 

[alldodge]

I have a 2001 Wellcraft Martinique with twin Mercuiser V6s. Engines have always performed well and my last tune up was about 60 hours ago. 3 weeks ago I took the wife, kids and neighbors on a sunset cruise. Both engines fire right up, and we motor out to watch the sunset. Once we get there I shut them down as normal.

When we want to leave, I fire both engines up. They each start fine but within 30 seconds they both stall out. From that point on I cannot get them started. They turn over, sputter, then die.

I got towed in. The next morning I come out and both engines fire right up (sigh). I let them run until they are warm and shut them down. Wait a while, and try again. They run just fine. I do this for a few weeks in a row (at my dock) and there is never an issue.

Today we take her out to the island. Both engines run just fine. We cruise out at about 3k rpms. Once i come off plane the port engine sputters then dies.

She will not start back up. We anchor hang out, then go home on one engine. On the way home I start up the generator and it runs just fine.

Once home i take off the flame arrestors and dump in some seafoam. I am then able to get the port engine running but now the starboard wont start.

I am frustrated and decided to go for help and drink a beer.

Any thoughts on this one? I have EFI and once the engines run they run great. Also, the generator seems to not have any problem.

Thanks for any help you can provide!

Something is going on with both engines, even though the last time it effected only one.

Personal opinion and no relevance on your issue "seafoam and the like are snake oil"

When was the last time the fuel filters were changed? Are you buying E10 gas or pure gas?

WHAT IS YOUR SERIAL NUMBER OF ANY OF THE ENGINES ?????????

 

[1flcheesehead]

Hi, thanks for the quick response. I have never used sea foam until now. It does appear to have a cult like following. I could not tell you if it works or not though.

I buy gas station gas (ethanol). I changed the water seperators last spring. Is there a fuel filter besides that?

I will get a S/N tomorrow. They are 2001 v6 efi mercruisers.

Is it possible there is some sort of a breather for the gas tank that got plugged? Seems kind of odd that they died at the exact same time before.

Thanks again.

 

[1flcheesehead]

I just got back from a cruise on the boat after I replaced both fuel filters.

The boat ran fine on the way out. I open it up wide then I brought it back on plane and it was fine. I shut it off and turned it on and it was good.

I motored out to do some fishing. I went to start it up about an hour later and neither engine would start.

I brought some tools so I pulled fuel filters. Both were almost empty.

i filled both up and the engines fired right up. The problem then was only one would stay running.

Any thoughts? Plugged something in the fuel tank maybe?

 

[1flcheesehead]

After researching the fuel fill I found out that this model (Perko) has a built in vent and the rubber o-ring was missing. I know it used to have one and it was deteriorating and must have come off with the last fill up.

Convinced that this missing o-ring allowed the cap to sit flush and therefore blocking the fuel vent, I replaced the o-ring and went back out on another journey.

Same deal. Runs fine on the way out, sits a while, then wont start. I checked both fuel filters (brought tools again) and sure enough, they were only 1/2 full.

The local marine mechanics will be charging $105 per hour to get it to fail, so that they can troubleshoot it.Any thoughts, even a guess would be greatly appreciated.

Thanks!

 

[Southtowns27]

Is there a way you can blow compressed air back through the fuel line(s) from the engine to the tank? Just make sure you take the fuel fill cap off when you do this! I wonder if your fuel line isn't partially plugged.

Edit: Wait a minute...I see you have MPI. I've never worked on an a boat that was fuel injected, so somebody has to help me out here, but where is the high pressure fuel pump for the injection located?? Is it in the fuel tank like on a vehicle, or is it a remote mounted pump? If it's a remote pump, is there a lift pump in or near the tank to supply fuel to the high pressure pump?
I'm wondering if there isn't an electrical gremlin with the fuel pump(s)...

 

[1flcheesehead]

There definitely is a gremlin, we just need to find him and evict him.....

Do you know if there would be one 'drop' into the tank that both engines feed from or would each engine have its own line right into the tank?

Also, would there be any sort of filter up near the tank or are the only filters on the engines?

What about an anti siphon valve? Do all boats have these and could that be my gremlin?

Thanks again!