Running an outboard engine out of water??

[DeLawterJ]

We hit a snag dropping the boat in this weekend and I want to know how badly I screwed up. The battery was dead and I jumped the battery with jumper cables at the ramp. The engine started up and then we backed her into the water. The motor was out of the water for no more then 20 sec at most. We docked the boat and the battery is now being charged. How major of a screw up did I pull off here. The motor sounded fine however I am just really nervous.

JD

 

[grouperjim]

agree w/FF.

 

[Totally Hooked]

20 Sec there hsould be no damage

 

[jcmcclellan]

starting the engine out of water for a VERY short amount of time will not hurt or overheat the engine. What it can and will do is cook the impeller. the rubber vanes on the impeller are quite stiff and produce a lot of friction in the water pump housing. The heat and friction generated is enough to damage and degrade the rubber vanes and score the housing even after only a few revolutions. The pee stream might look great now but twenty miles from shore it could let go and not look so great. A cheap penalty to pay for your boo boo would be to replace impeller and housing.

 

[dave11]

starting the engine out of water for a VERY short amount of time will not hurt or overheat the engine. What it can and will do is cook the impeller. the rubber vanes on the impeller are quite stiff and produce a lot of friction in the water pump housing. The heat and friction generated is enough to damage and degrade the rubber vanes and score the housing even after only a few revolutions. The pee stream might look great now but twenty miles from shore it could let go and not look so great. A cheap penalty to pay for your boo boo would be to replace impeller and housing.

Sad but true. I agree.

 

[MaxOut]

starting the engine out of water for a VERY short amount of time will not hurt or overheat the engine. What it can and will do is cook the impeller. the rubber vanes on the impeller are quite stiff and produce a lot of friction in the water pump housing. The heat and friction generated is enough to damage and degrade the rubber vanes and score the housing even after only a few revolutions. The pee stream might look great now but twenty miles from shore it could let go and not look so great. A cheap penalty to pay for your boo boo would be to replace impeller and housing.

Sad but true. I agree.

I do not totally agree.
:arrow:
Impellers most always start dry. The water is below the pump housing and is primed into the pump while it runs dry. Just like marine and RV water pumps will pump for up to a minute before getting water primed from the tank on the initial run after draining the system. I forgot to turn off my SWW pump one day and drove the boat home on the trailer nearly an hour away. I found the pump running dry when I got home and turned it off. The next trip I expected the pump to be shot....It ran fine and pressure was as good as always still to this day. I have seen mechanics (not going to mention where) run outboards out of the water while they fog them for winter storage year after year with the same impeller. I always error on the side of caution when it comes to engine maintenance and probably would replace or at least inspect the pump.

That been said I do not recommend running the engine dry...ever, but if it is pumping fine and not overheating at idle or speed and you only ran it for 20 seconds chances are you did no real damage.

 

[DeLawterJ]

Seeing that this is boating spending 12 bucks vs 1200 I will take a peek at the impeller. Now here is the fun part, how difficult is this to do. I have looked at some sites and some one help me out here.
Can this be done with the boat still in the water? ie lift the engine out and work from the dock?

2003 115 Yamaha four stroke

Or better yet how much will this cost me to have a tech do this? Any help is awsome

JD

 

[Totally Hooked]

Max out most SWW pumps do not have impellers rather than they are diapgram pumps which cam erun dry for ever. I uses these pumps everyday at work and i have seen customers runn them dry for 2 weeks .

The water pump is a pretty sim[ple job although i would not recomend doing it while the boat is in the watre. That might might make it tricky.

 

[MaxOut]

Max out most SWW pumps do not have impellers rather than they are diapgram pumps which cam erun dry for ever. I uses these pumps everyday at work and i have seen customers runn them dry for 2 weeks .

The water pump is a pretty sim[ple job although i would not recomend doing it while the boat is in the watre. That might might make it tricky.

You are correct my Johnson pump is a diaphragm pump.

I agree do not attempt to replace pump while in water.

For what it is worth if you are concerned Replace It!, It is cheap piece of mind.

 

[DaleH]

SWW :?:

Are you implying some Yamahas have diaphram pumps?

All: I believe SWW = "Salt Water Washdown" pump ... and if so, I would agree that the TYPICAL 'pressurized' washdown pump, e.g., Shurflo, Aqua-Jet, Flo-Jet, et al, is a diaphragm type. But other SWW pumps use magnetically-coupled drives to engage a plastic impeller. Those are usually the ones you see labeled as 'run dry forever'. I would have guessed diaphragms would be labeled or claimed as being able to "run dry without damage", but forever sure is a long time :lol: !

That said, an OB pump is most definitely a FIXED-DRIVE impeller pump, meaning she's always engaged whenever the flywheel is turning, unless the drive key is broken.

 

[Micheal J]

starting the engine out of water for a VERY short amount of time will not hurt or overheat the engine. What it can and will do is cook the impeller. the rubber vanes on the impeller are quite stiff and produce a lot of friction in the water pump housing. The heat and friction generated is enough to damage and degrade the rubber vanes and score the housing even after only a few revolutions. The pee stream might look great now but twenty miles from shore it could let go and not look so great. A cheap penalty to pay for your boo boo would be to replace impeller and housing.

Sad but true. I agree.

It's not the impeller that gets damaged quickly,it's the PLASTIC housing....been there done that....it only took about 20 secs,and it was melted
MJ.

 

[Ranger Tim]

Ditto what Michael J said. Although it was more like thirty seconds for me. It still ran with a stream but it was reduced so I replaced it. Glad I did. It does not cost anything to pull and inspect. Not that difficult either - at least out of the water. I wouldn't try with the boat in the water.

 

[Pain Management]

If you look at my post a few days age "first problem of the season" you will see that I was having a water flow problem. I pulled the boat early Sunday dropped the lower unit and cleaned the water pump parts. I also cleaned the popit valve and flushed every thing out real good to include the stats. Very easy to do and was back in the water by 5:00 running good. Water pump inspection, cleaning or replacement is a easy job. The popit is easy but time consuming (considering there are only two bolts) because you are working in a tight area. You can drop the lower end if you don't mind getting in the water but it is much easier I would think on a trailer. Good luck....
George