Pontoon Boat & Deck Boat Forum

A buddy of mine pulled his pontoon out of the water and hit the master switch to kill the motor. About 2 minutes later he realized motor was still running. Master switch kills everything else but motor. I was at least 100 deg out that day, but the motor was simply idling. Motor is an outboard Yamaha. Damage done?

My best guess is if it was only 2 minutes at idle no damage was done. Water pump would probably be the first thing to go and since it started wet I wouldn't worry about it if it has good water pressure now. When I did that my 2 cycle Johnson was noisy enough I knew what I had done the minute the motor was out of the water...I pulled up out of the way and redfacedly shut it off...No harm done.

WOW!

And +1 on the impeller, I would replace it.

Water pump would be highly suspect. even with starting out wet the impeller is still only mad of rubber

Check to see if the alternator still works. Running without a load is not a good thing.

Maybe a silly question, but if there were some kind of damage, wouldn't an alarm have sounded before hand?

ROLAND wrote:Maybe a silly question, but if there were some kind of damage, wouldn't an alarm have sounded before hand?

Probably not until major damage had happened already, temperature sensor usually need liquid passing by them to be accurate on liquid cooled engines. It takes along time for heat to transfer through the block or head to get where the sensor is with no coolant flow. Also most outboards don't have a Water pressure sensor either which in this case would have been nice as it would have tripped an alarm as soon as the pressure hit zero. In his case 2 minutes probably only will cost him a 50$ water pump impeller. I've messed around with some junk cars and got over 45 minutes of idle time out of an engine without coolant in it!

babock wrote:Check to see if the alternator still works. Running without a load is not a good thing.

Huh???

Tlowry wrote:

babock wrote:Check to see if the alternator still works. Running without a load is not a good thing.

Huh???

Which part didn't you understand?

babock wrote:

Tlowry wrote:

babock wrote:Check to see if the alternator still works. Running without a load is not a good thing.

Huh???

Which part didn't you understand?

Well, let's keep this short and talk in layman terms please. Could you explain how running an outboard in the water vs out of the water affects the load on the alternator?

We are talking different types of loads. Nothing to do with being in the water obviously. By turning off the battery, you have removed the battery load from the alternator. This can cause huge voltage spikes that can damage it.


Never ever ever turn a battery switch to off while engine is running.

I see your point but wouldn't this only be true if the master switch was a Pergo style switch that disconnects the batteries from the motor and the boat?

My older boats master switch disconnects just the boats fuse panel from the battery but leaves the battery connected to the motor and its charging system. This is important if you want to tilt the motor with the master switch off.

Tlowry wrote:I see your point but wouldn't this only be true if the master switch was a Pergo style switch that disconnects the batteries from the motor and the boat?

My older boats master switch disconnects just the boats fuse panel from the battery but leaves the battery connected to the motor and its charging system. This is important if you want to tilt the motor with the master switch off.

On my boat, the master switch is a Perko type switch and it came that way. I know its a hassle but I prefer being able to disconnect all power from the motor. To me. its a safety issue in case something goes majorly wrong. Example...starter solenoid sticking.

I saw this happen not that long ago at our boat ramp. Guy drove off with his stern drive running! He was hammered though! I agree, impeller and if parts are missing, back flush the passages. The parts can get caught in the piss tube and t-stats.

Had this happen on a 115 once. Piece of the impeller came off and went into the feed tube to the power head. It restricted the flow to where it would overheat if run on plane for around a mile. Took a while to figure it out cause at slower speeds, I got no alarm.