HELP!! 2001 240 Sundeck Guardian / limp / failsafe mode?

[Original_704]

Hi everyone,
I have a 2001 240 Sundeck with a 5.0 / Bravo 3 outdrive.
I have an issue that only happens 1 out of 20 times so its intermittent.
If we happen to go out for a ride and shut off the boat to float sometimes when we try to start our boat back up it goes into some sort of failsafe mode where its idles up and down a few times and then shuts off. Most times if I wait 20 to 30 minutes and try it again it starts up perfectly and run fine.

I'm thinking maybe the water temp is still to high but looking for any advice.

Thanks Dan

 

[ColoSR]

Is the engine throwing codes? If not, it could be vapor locking. You can run the blower when going slow and at shutdown to prevent it. Some use the sprayer to cool down the fuel pump. there’s a tsb for it below.

https://stu-in-flag.net/blog/wp-content/uploads/2014/08/vaporlock.pdf

 

[b_arrington]

It does sound like vapor lock is a possibility. The engine temps can rise dramatically after engine shut down, causing heat soak and vaporization of fuels.

Some ways to mitigate the effects of heat soak and vapor lock:

• Run the blower when idling or going slow. This will help expel heat from engine space.
• Don't shut the engine down right away after a run. There's lots of residual heat that will build up in the engine space. Instead, let the engine idle for a few minutes - either on the way to your dock / mooring or once you arrive. This will allow the cooling system to draw heat out of the engine in a no-load condition and reduce heat soak. It's a good engine management practice.

Try these the next few times you go out and see what happens.

Just as a reference, I have a diesel generator on my boat. The highly recommended practice for generator longevity when shutting down is to remove the loads on the generator and allow to run in a no-load condition for minimum 2 minutes before shut down. I've observed on the status panel that the operating temps will drop significantly during those few minutes, but can rise a few degrees after shut down.