Damage from running without muffs?

[avpro91]

How much damage would running the engine for 5 minutes without the muffs do? How long would it take to damage anything? What would you damage? And how would you know you damaged something?

I have a friend who tells me he did this for about 5 or so minutes to warm the engine for an oil change. Thanks.

 

[Don S]

Re: Damage from running without muffs?

You would destroy the raw water pump impeller for sure, and probably burn up the hoses in the exhaust system. Hard to say if the engine was damaged or not.

 

[avpro91]

Re: Damage from running without muffs?

Don- Thanks for the quick reply.

All the hoses check ok, and its been out numerous times since then with no problems or cooling issues. Everything runs and looks fine...does this mean he got lucky or theres something wrong that we just can't see?

This happend prior to the end of last year and the boat has been to the dealership and winterized since then. If there was any damage caused wouldn't they have noticed it?

 

[SHGOTME]

Re: Damage from running without muffs?

Depends the motor, five minutes wont hurt an I/O although it's not recommended you run it any longer. There should be enough residual water in the water pump to lube the impeller. Five minutes will not produce enough heat to damage hoses. I run my 4 cylinder Volvo disconnected for a few minutes before I depart for the ramp, been doing it for seven years and have not had any irregular wear or damage.

 

[Bondo]

Re: Damage from running without muffs?

Regardless of Who saw What,......

I'd replace the Impeller immediately,+ Inspect the Exhaust Flapper Valves,...

The Impeller is Toasted in a matter of Seconds running it Dry,.......
And,....
The Flappers don't last very long with Hot Exhaust Gases Frying them......

 

[avpro91]

Re: Damage from running without muffs?

It's a 6 cyl 4.3L 190hp carb mercruiser

 

[AlanR]

Re: Damage from running without muffs?

Regardless of Who saw What,......

I'd replace the Impeller immediately,+ Inspect the Exhaust Flapper Valves,...

The Impeller is Toasted in a matter of Seconds running it Dry,.......
And,....
The Flappers don't last very long with Hot Exhaust Gases Frying them......

x2 Dosnt matter what it looks like right now Id replace the impeller even if it only ran for 2 mins. There just little peices of rubber guys I also disagree with Shgotime i wouldnt run my i/o with out muffs or water for more than 20 seconds beause it takes only a mintue to write off your Impeller.

 

[Boomyal]

Re: Damage from running without muffs?

If you read the manual it is peppered with warnings not to run without water, even for a few seconds. I would head that advice.

Water both lubricates and cools. Without it you do damage two different ways.

 

[SHGOTME]

Re: Damage from running without muffs?

How much damage would running the engine for 5 minutes without the muffs do? How long would it take to damage anything? What would you damage? And how would you know you damaged something?

I have a friend who tells me he did this for about 5 or so minutes to warm the engine for an oil change. Thanks.

To answer your question and not look like an idiot...
Remove the sea water pump cover plate and check the impeller for damage or tares, pay close attention to the inside wall of the pump housing for signs of rubber adhered to the metal, if the impeller is damaged replace it, the impeller should be replaced every 100 hours or every two years regardless, if there is a build-up of rubber on the housing wall clean it with a solvent to remove the rubber do not use anything abrasive or scratch the surface. Remove the elbow and inspect the flappers, look for cracks, tears and bend the flapper to check for brittleness. [colour=null]New man law states... thou shall not let buddy run the boat without water connected. Penalty for committing such an offence will result in a lifetime of giving bad advice.[/colour]

 

[bruceb58]

Re: Damage from running without muffs?

Last year I lowered my stern drive onto the water hose and that was feeding my muffs and pinched it off. I didn't notice what had happened for around 2 minutes. I took apart my raw water pump to see what it looked like...it was pretty well cooked. All the blades were there but were severely distorted. This impeller had only around 30 hours on it.

 

[wcsparky05]

Re: Damage from running without muffs?

remember, if you think you can, or you think you cant, you're right!.....stewie griffin.seconds. these guys know. take your lower unit apart and inspect your impeller. it will look melted. but thats the best thing that could have happened. they are cheap. just make sure yoiu didn't do any worse damage!

 

[I/O WALDO]

Re: Damage from running without muffs?

(its been out numerous times since then with no problems or cooling issues. Everything runs and looks fine... Amazing things happen every day! Maybe he has one of those Globe brand "blue" impellers that is supposed to be able to run several min.with no damage.

 

[SteveNix]

Re: Damage from running without muffs?

Take a look at the impeller. And since you're already looking at it, replace it too!!!
Cheap and quick fix.

 

[avpro91]

Re: Damage from running without muffs?

Okay, thanks for the responses.

This boat has a 2004 4.3l i/o with and alpha drive on it (pretty sure gen 2 #OM458288)

So do we just need to pull the cover off the water pump on the front of the engine to get to the impeller, or does the lower unit need to come off to get to it and inspect it?

 

[SHGOTME]

Re: Damage from running without muffs?

Yes, check to impeller on the engine, there is no impeller on the lower unit of that out drive (wcsparky05), or anything else you need to inspect after a five minute dri run. Your going to be ok, just a lot of drama because I don't belong to the 5000 post club, funny thing about these boating sites...

 

[Don S]

Re: Damage from running without muffs?

Yes, check to impeller on the engine, there is no impeller on the lower unit of that out drive (wcsparky05), or anything else you need to inspect after a five minute dri run. Your going to be ok, just a lot of drama because I don't belong to the 5000 post club, funny thing about these boating sites...

Want to explain items 18, 27, and 22 there shgotme? Since you say the Alpha drives don't have a pump in them.
If you are wrong about that simple fact, wonder what other wrong info you may be giving out.

 

[avpro91]

Re: Damage from running without muffs?

Thanks for the pic Don. How much work will this actually be since we've never taken the drive or any part of it off a boat before? Just the lower required or whole thing?

Is a Selco manual good for this or do I need to find a factory manual from mercury?

And should we just replace the inpeller or get the repai kit with the gaskets, or the the whole thing with the housing and all?

Or since it runs fine and doesn't overheat, can we just wait till the fall and do it all then when it gets winterized?

 

[Bondo]

Re: Damage from running without muffs?

Or since it runs fine and doesn't overheat, can we just wait till the fall and do it all then when it gets winterized?

I Wouldn't............

Even though the Gen.II drive's Waterpump is more Forgiving than the older Alphas,.....

I'd spring for the Repair Kit,.... Now.........

 

[avpro91]

Re: Damage from running without muffs?

Ok, I think we are going to check and replace the impeller.

But what about the water pump on the front of the engine? Does that need to come off and the impeller in there checked too???

 

[Don S]

Re: Damage from running without muffs?

Here is a link to the Mercruiser online service manual. Just run your cursor over the red box that says sterndrive unit and click it. Then click on the section you want. Section 3B will show you how to repair the pump.
I would suggest you pull the drive to repair the pump as it's easier for the first timer.
You can also check the exhaust to make sure none of the flappers burned off and are lodged in the exhaust tube.

http://www.boatfix.com/merc/Servmanl/14/14cover.pdf