Help Engine Cuts out !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!

[Dave Sea Ray]

My port engine cuts out when shifting at low RPMS at a speed of 1 to 2 knots.Forward to Neutral or Neutral to reverse.This only happens after the engines have been running for a few hours and always when popping in and out of gear, trying to dock or return to the slip.The engine just cuts out, then if you try to start it back up, it will just crank and not turn over. After letting it sit for about 1 hour it will start right up like nothing is wrong.This only happens after the boat has been running for a hour or more.Never happens when you first start running the engines, no problem popping in and out of gear when leaving the slip.I had 2 mechanics look at this,there are no codes on the computer.

Has anyone heard of this before ? If so what was the cause ? What was the fix ?


Any feed back would be greatly appreciated.


Thanks

2005 300 Sundancer 5.0 LT MPI 260hp w / Bravo III

 

[trit21]

When I had my 280 years ago, it would be hard to start due to fuel vapor locking. Combination of ethanol fuel and heat inside the ER would cause the fuel to vaporize in the fuel line and the only way to restart would be to let the boat sit, then no problem. BUT, mine did not die when shifting only if I was to shut it off HOT and try to restart. Might be a combination of vapor locking and low idle causing the stall? Always hated that problem.

 

[trflgrl]

We had a shift cable problem that caused an engine to die when moving from neutral to either forward or reverse. It was intermittent over all, though--there was no difference in cold start vs. after running a while, and the engine would restart with no issue. Shift cable likely was original to the boat and was beyond the point of a simple adjustment; dying engine problem resolved immediately when we replaced it. On your much younger boat, it may be worth a try to adjust, because you should be able to restore the cable to its current state easily if it doesn't help the situation.

 

[MasterFab]

Alpha drives utilize a shift interrupt switch to momentarily stall the engine during gear disengagement - when shifting out of forward or reverse. A tight and aged shift cable will cause shifting issues as trflgrl described. This system is required on an Alpha drive because the shifting takes place in the lower unit, via a back-cut shift dog that holds itself engaged when load is applied to the props. A momentary ignition interruption allows the dog to release and move into the neutral position.

On a Bravo drive, none of this applies. Bravos utilize cone clutches located at the rear of the upper drive unit, and there is no shift interrupt switch on the exhaust manifolds like an Alpha. Additionally, on a 2005, the engine PCM controls the idle speed via the IAC, so this should also not be the issue, barring any faults in this circuit. It sounds like a vapor lock issue, but without more testing, specifically fuel pressure during the event, it is hard to say. If it was my boat, I'd be monitoring fuel pressure.

Good luck with it.....

Dale

 

[Chris Nowell]

I'm thinkin' some kind of fuel problem, vapor lock or something. The OP needs someone with "hands on" to respond. This is probably an issue that has plagued numerous owners of the EFI and MPI engines. We too experienced the cut out switch blues with most of our Alpha drives at one time or another. As MasterFab stated,"Bravos are a non issue" when it comes to cut out switches and shifting. Good luck. I'm sure someone will be able to point you in the right direction, just gotta give it a bit of time. There are a number of guys on this forum who have an unbelievable amount of experience that they're willing to share with us all. And BTW, welcome to CSR.

 

[Dave Sea Ray]

Thanks for your help.