Engine stalls and only starts several hours later

[Ralph vaughn]

I have a Sea Ray Sundancer 290 with dual 5.0 Sea Core engines and B3 drives.

My port engine last Friday stalled while at idle. I wasn’t able to restart until the next morning. When I started the engine it ran for ten minutes and stopped again. wouldn’t restart. I just replaced the relays for the fuel pump, engine power and trim tabs.

Any idea what the problem might be? Electrical of fuel related?

Thanks in advance for your help

Ralph

 

[CaptRonn]

Define restart. Would the ignition energize or not? Does the engine turn over and not fire?

 

[scoflaw]

You need to check for both. Got spark? Got fuel?

 

[Ralph vaughn]

Engine turns over normally but does not start

 

[paulswagelock]

Spray carb cleaner in the flame arrester and try starting. If it starts, fuel issue, if not, spark issue.

I suspect electrical and it fails when hot. I have seen the fuel pump fail when hot and not work, and when it cools the pumps work again.

 

[capecodcruiser]

"My boat won't run, tell me why..". You need to put a little more effort into this before coming to the internet and asking a question that has 500 possible answers! Spark, fuel, electric! Do some homework, than come back

 

[Ralph vaughn]

Thanks cape cod cruiser. You are very intuitive. If I was a mechanic I wouldn’t be addressing this forum and I would have all the answers. I’m not so I so I try to get some ideas on troubleshooting. I wish I was as intelligent and knowledgeable as apparently you are then I would know exactly what is wrong with my engine

 

[CNYBoater]

Ralph, I’ve read to many threads devolve. Best to just skip over the occasional post.

Can’t offer any insight on this as I’m an outboarder but in general the comments of spark or fuel are right on the money. If you hit the local auto parts store, they can point you to the basic diagnostic tools that would be handy to have in your diagnostic toolkit.

are you familiar with testing for spark and if getting adequate fuel pressure?

edit: oh, and try a forum search. I remember reading a thread about what tools people keep on the boat, etc. might be helpful.

 

[BillK2632]

Another possible cause is vapor lock. Classic symptom is engine stalls or won't restart after a shutdown, but then will start and run fine after several hours. Vapor lock is when the fuel in the fuel line heats to the point it vaporizes, fuel pumps can't pump vapor, only liquid fuel. As a result engine behaves like it is out of fuel. It usually happens when you have been running, shutdown and then try to restart after 30-60min. The temps in the engine room continue to rise after shutdown and will heat up and vaporize the fuel in the fuel lines. Mercrury installed the CoolFuel systems in their inboard engines to try and resolve this issue - it is worse on some engines due to engine / fuel system configuration.
My 290DA would vapor lock occasionally - it did not have a CoolFuel - I even had it vapor lock on a very hot humid day just after startup, pulling out my slip at idle one engine shutdown from vapor lock - so it can even happen on a running engine. My solution was to run the blowers for a period after shutdown to reduce engine room heat. When it did happened, I would pour fresh water over the fuel line, this does basically what the CoolFuel is supposed to do - that would usually solve the vapor lock.

Fuel can also contribute - high octane, winter blend and ethanol fuels will vaporize at lower temperatures.

Here is a service bulletin from Mercury regarding vapor lock:

 

[Ralph vaughn]

Thanks everyone for your insightful positive comments. You have provided me several
Avenues of troubleshooting my engine problems. Thank you so much for sharing your expertise with a novice mechanic. I would like to hand this over to a capable mechanic but my local guy says he’s at least 4 weeks out until he can look at my engine. So I’m going to try to resolve the problem with my very limited diagnostic skills that you girls and guys are so graciously helping me with.
Ralp

 

[Strecker25]

You’d have to verify this applies to your engine because my experience was on a 98 TBI model but those exact symptoms turned out to be heat soak into the ignition module under the rotor in the distributor. It got hot and would begin to cut out, often refusing to restart until it cooled down.

 

[ttmott]

That engine is fuel injected and requires a device called an Idle Air Control (IAC) or sometimes called Idle Air Motor (IAM). This device electrically adjusts the amount of air the engine receives when idling and is operated by the engine's electronic control module or usually called ECM. The IAC is responsible for engine idle stability and speed when the throttles are closed. Many times engine idle issues are related to the IAC not operating correctly or getting dirty or gummed up; they can also be temperature temperamental when not working correctly.
Usually if you can advance the throttle a bit and the engine will start and run and operate nominally it is this IAC that is the issue. The IAC is not in use when the throttles are advanced above the closed position.

 

[Black Valkyrie]

No one makes a diagnostic code reader for mercruiser? There are a million plus one for vehicles... I have a full software suite for my BMW. This hasn't been an issue for my older 93 so I have done zero research into this - just thinking out loud.

 

[Strecker25]

No one makes a diagnostic code reader for mercruiser? There are a million plus one for vehicles... I have a full software suite for my BMW. This hasn't been an issue for my older 93 so I have done zero research into this - just thinking out loud.

Rinda does, but it's like $500 so most people don't bother. I bought the rinda codemate for my old engines which is a fancy LED. You can make an LED code reader for like $10 and jump the pins (on the older EFI at least)