Cranking outboard motors for a second when out of water.

[calvinyonce]

We have a lot of different types of outboard motors at my job and when I arrived it was common practice to crank the motor on the trailer out of water before leaving the office to make sure it will crank when we reach the river. I was always told by my outboard mechanics that this is a very bad because the impeller can either break off one of the rungs or wear on the ends where the impeller touches the water pump housing. The good folks at work say they have never had any problems with this but they replace the water pump impellers yearly anyway due to the nature of the water we run the motors in. They also have said that there should still be some water in the housing from the previous usage, which I don't think is correct. The Missouri river has a lot of silt suspended in the water and they are saying it wears the impellers down enough that dry starting them wont matter. To my understanding even if the impeller does not essentially break off or be damaged so much it doesn't work at all even wearing it a little could cause poor pumping of the cooling system and thus causing prolonged damage to the power head and other parts of the motor. What would everyone's recommendation be here. Any insight into cranking outboards dry would be much appreciated. One of my coworkers even suggested that you can run the motor dry for 20 seconds with no problems, I am positive that would lead to a variety of problems.

 

[GA_Boater]

It is not a good thing to do. It sounds like some of your co-workers relatives have the outboard maintenance contract.

 

[robert graham]

Starting outboards without water is just a bad idea....you might get by with it some but it's still just a bad idea....

 

[wrench 3]

I'm having a little trouble deciding if we're talking about just spinning the engine over or talking about firing it up. It is fairly common to do a compression test with no water. However getting it above cranking RPM is definitely a no no.

 

[bobsquatch]

If you tip the motor up and water still runs out from the last swim I would have no problem cranking it over to insure that it will start and immediately shutting it down. If it has been land locked more than a few days put on the muffs to be safe. If there is any water present it is fine for three seconds, if it is dry, turning it over by hand could do damage. Daily dunk motors can stand a function test sans the muffs. Just don't get brave with the time or the throttle.

 

[calvinyonce]

We are just turning the key on the ignition to see if the motor has compression and will ignite for a second. We are not operating the throttle and the motor is in neutral when the key is turned for a second. Sometimes the boats have just been in the water but more often they have sat land locked for a week or two in freezing temperatures. So it sounds like this practice may be alright if its done only for a few seconds and if the water pump housing still has some water in it. All of the motors are 150 to 175 hp Evinrudes and Johnsons. Thanks for all the replies I appreciate the info.

 

[jimmbo]

As said before it's not a wise thing to do. I know many people will pipe up saying they did it for years and never had a problem. So what! It is still a bad idea

 

[Dukedog]

Anytime ya turn a "dry" impeller it takes something away from it and shortens tha life of all tha pump parts. even comp tests.....

 

[Sea Rider]

Water goes down by gravity, if motor sits at a vertical position, impeller and liner should remain way dry for next day outing.

Happy Boating

 

[bobsquatch]

Adding freezing temperatures to the mix is another reason not to do it as the ice may grab hold of the impeller and tear it apart it freezes to the housing

 

[Fed]

I've changed quite a few and even after standing for many Months they have always still been wet.
A little short on detail but I'd say this test would have been conducted bone dry @ idle RPM.

 

[gm280]

I won't do that without muffs and good water flow first. But I never back the boat from the trailer without firing up the engine at the lakes either. So many back up their trailers and instantly float their boat off and go park the trailer. I never ever do that because if it doesn't start it stays on the trailer... I've seen folks push off the ramps and then connect their fuel lines up and start priming the fuel bulb and then try to start their engine. And a lot never get it to crank. And the paddles come out and hit the water to get back in... But different folks have different opinions and to each their own. What I think has zero to do with what others think...

 

[boobie]

The only thing I can say is put it in the water or put some muffs on it before cranking it over.

 

[UncleWillie]

You are going to get a different opinion from everyone you ask.
The question was if running it for "a Second" without water will cause damage.
The answer is Yes! But if the amount is of any significance is another question.

If the engines are so highly maintained that the impellers are replaced yearly, the question of if they will will start should not even enter your mind.
If you are going out on the water with an engine that you need to test before every launch, something is fundamentally wrong.
If you do not have the confidence that the engine is going to start the first time, every time, you can not have the confidence that the engine will get you home with any certainty and should not be risking your welfare in the first place.
There should be no reason that you should not be willing to launch the boat without testing the engine and fully expect the engine to start on the first try.

 

[Bosunsmate]

If i saw any shop do that to a boat i wouldnt let anyone take their boat there again.
If they are doing that what else are they doing you think is not right?

 

[racerone]

Today's equipment is very reliable and there should be no need for a " test crank "---Bad for the impeller.---------Ever wonder what an airline pilot thinks when he steps up to a a jetliner that he has not flown for say 2 years or more himself ???

 

[gm280]

Things folks need to consider about OB engines and water pumps. When you install muffs on your OB and turn on the water, you have successfully pushed water up to the water impellor and it is lubricated with that water for start up. When you put your OB in the lake (or river) again you allow water to seep into the water pump system for lubrication upon start up. But when you simply crank any OB without water you take the change that there is zero water/lubrication at the impellor and therefore friction starts instantly and can cause wear very quickly. I know some think there is left over water in there, but that really depends when the last time it was cranked... Just some info...

 

[Fed]

I'm sure those airline pilots run their engines before they take off.

 

[NSBCraig]

Im a start it on muffs, let it warm up, then go to the ramp guy.

I dont want to be that guy stuck there messing with it. It happens, I just try to prevent it.

 

[UncleWillie]

I start it on muffs, let it warm up, then go to the ramp guy.
I don't want to be that guy stuck there messing with it. It happens, I just try to prevent it.

I totally understand your logic.
But what you are really saying is that you do not have enough trust in the engine to put the boat in the water and expect the engine to start every time.

No airline pilot goes out and tests that the engines will start and then declares that it OK to start loading the passengers.
The passengers are often loaded before the pilots even arrive at the plane. They arrive in the cockpit of an airplane that they may not have ever personally flown, with every expectation that the engines are going to start the first time, every time!

I am a licensed pilot, and commonly fly rental aircraft that I have never flown before.
Everyone is buckled in before I even attempt to start the engine. I full expect that engine to start and run without issue.
It is not unusual, at a small airport, to be in the air within 5 minutes of engine start.
I am trusting that engine with my life. I have the same level of trust for the engine in my boat.
Being 20 miles offshore in Lake Erie is a life endangering situation if the engine quits.
I will happily go out there with the confidence that I am coming back without incident.

I shake my head at the guys I see at the ramp spraying starting fluid in their engines because they completely expect that it will NOT Start without it!

Either Trust that your engine is totally reliable, or do whatever it takes to make it so.