Starting boat out of the water

[madcityskier]

Originally Posted by Red 08 Xstar

This is absolute misinformation. I start my boat all the time out of the water. When I winterize it at the end of the season the impeller is fine. I'm on the same impeller for 4 years now and it still looks like new.

So the guy who drives drunk all the time and hasn't killed anyone yet proves that drinking and driving isn't a bad thing? I know that's overstating things, but that's the logic you're using. Everything works, until it doesn't. You're way past the useful life of that impeller. It'll be fine till it isn't. Then when your engine overheats, I hope you're watching your temp gauge and shut it down before it does major damage. Ask yourself if a thirty dollar part and a few minutes are worth the risk to your engine.
Bumping is iffy, dry starting is a mistake, imo. But we're all allowed to make our own mistakes.

[ski/hunt]

Starting your motor "dry" and then not replacing your impeller after 4 years is like Bull riding without health insurance!!
Both are things I just wouldn't do!

[mikeg205]

Impeller should be changed every 100 hours or annually... as MC puts it...Blockage of the transmission cooler or a faulty raw water impeller are too-frequent causes of overheating.

running it dry will cause vanes to where causing less water to be pumped into cooling jacket. Rubber against metal no water or lubricant...heat... Impeller - $35, Engine work/replace $3K - $10K, replacing impeller seasonally or every 100 which ever comes first and not worrying about it....pricelesss.

[JimN]

Originally Posted by Red 08 Xstar

This is absolute misinformation. I start my boat all the time out of the water. When I winterize it at the end of the season the impeller is fine. I'm on the same impeller for 4 years now and it still looks like new.

It may look like new but I guarantee the vanes don't push back on the housing like they need to, in order to provide sufficient water flow rate. Having seen and replaced numbers well into the hundreds of impellers that were missing vanes, I'd rather be safe than cheap.

Look at it this way- what's the cost of an impeller and gasket vs the cost to repair the damage from one that lets you down when you least expect and least want it to?

[wtrjock]

I agree with the priceless statement. I was dead in the middle of the lake this summer because I went cheap this year and didn't replace my impeller.

I will definitely replace it every year from now on. When our boats overheat...they just shutdown and kill all power to the motor.

Make sure you have a spare in the glove box also!

Sent from my EVO using Tapatalk 2

[erkoehler]

Originally Posted by JimN

It may look like new but I guarantee the vanes don't push back on the housing like they need to, in order to provide sufficient water flow rate. Having seen and replaced numbers well into the hundreds of impellers that were missing vanes, I'd rather be safe than cheap.

Look at it this way- what's the cost of an impeller and gasket vs the cost to repair the damage from one that lets you down when you least expect and least want it to?

I agree with Jim, replace it annually! When the impeller fails while the normal driver/owner is skiing and your buddy doesn't pay attention to the temp gauge you'll really regret not replacing that part for less than $50!

I guarantee the repairs will amount to a number greater than a case of impellers!!!

Sent from my DROIDX using Tapatalk 2

[JimN]

Originally Posted by erkoehler

I agree with Jim, replace it annually! When the impeller fails while the normal driver/owner is skiing and your buddy doesn't pay attention to the temp gauge you'll really regret not replacing that part for less than $50!

I guarantee the repairs will amount to a number greater than a case of impellers!!!

Sent from my DROIDX using Tapatalk 2

One of the biggest problems with impellers going bad is the fact that the ECT needs to be immersed in coolant and hot air isn't as good of a good conductor of heat as any liquid, so the engine can be badly overheated without showing an overheat on the gauge.

[mikeg205]

Originally Posted by JimN

One of the biggest problems with impellers going bad is the fact that the ECT needs to be immersed in coolant and hot air isn't as good of a good conductor of heat as any liquid, so the engine can be badly overheated without showing an overheat on the gauge.

'nuff said' - good point Jim...

[GoneBoatN]

Originally Posted by mikeg205

Impeller should be changed every 100 hours or annually... as MC puts it...Blockage of the transmission cooler or a faulty raw water impeller are too-frequent causes of overheating.

running it dry will cause vanes to where causing less water to be pumped into cooling jacket. Rubber against metal no water or lubricant...heat... Impeller - $35, Engine work/replace $3K - $10K, replacing impeller seasonally or every 100 which ever comes first and not worrying about it....pricelesss.

Funny thing is I notice my mastercraft manual (2010) says to change the impeller every 100hrs while the Indmar manual says to inspect every 100hrs and change every 2 years.

[CantRepeat]

If you want to run YOUR boat while out of the water fine, do it. But suggesting that others do is extremely bad advice.

You cannot dispute the scientific facts of heating up rubber. Heating up the impeller(rubber) will change the molecular properties of the rubber. The thermal and physical effects, as Jim pointed out, will surely weaken it. So if you don't get a complete or partial failure, surely you will get lower water volume/pressure. Just because you can't see any damage does not mean that it hasn't already happened. Why take the chance? Is $30 bucks for a new one each year worth it? Is not changing it and wasting a motor worth it?

I'm not all that smart when it comes to science but it's pretty easy to see that heating up an impeller is never a good thing. Sure you might get away with it a few times, or forever. But at some point it will catch up to you.