15 Seconds. Long enough to trash an impeller?

[TomB985]

Hey everyone,

Two weeks ago I was finally able to dust off the boat and check things over in the driveway. I hooked up the muffs and let it warm up around 1,300 RPMs. Of course nothing ever goes according to plans, and as I was moving my floor jack back into the garage it yanked the hose which pulled the muffs right off. I sprinted to the boat as fast as possible, but I suspect it ran for a good 15 seconds before I was able to kill it.

Not real sure if I did any harm or not, yesterday I took it to our local lake for a quick dry run. I noticed that when cruising above 3,500 RPMs the temp gauge was getting warmer than it ever has, just a hair over 175. It's never gotten above that before, and when I start feeling around afterward it seems that the manifolds are warmer than they normally are.

So does it look like I cooked my impeller? What do you guys think?

 

[Don S]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

If the temp went up from before the incident, then you have impeller damage.

 

[TomB985]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Thanks for the quick reply, Don. Last night I ordered a quicksilver impeller replacement kit

47-43026Q06 for nearly $50 including shipping. Just this morning it looks like iBoats sells aftermarket impellers for much less, but it looks like they include just the impeller and nothing else. Can I get by with just the impeller, or should I still get the entire Quicksilver kit? ​

 

[Don S]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

You will probably need the kit, it has the gaskets, one problem about the aftermarket kits that iboats has, is they don't have the face seal or installation tool included in the kit. And with not cooling water, your old one probably burned off. Here's some info on replacing the impeller.

View attachment A1G2 Impeller Replace.pdf

 

[TomB985]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

THANKS! I'll be tackling this one next weekend!

 

[TomB985]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Okay, so I have a couple of newbie questions:

First of all the manual that you posted states that I should use Quicksilver Perfect Seal to seal the gaskets when I reassemble the water pump. Is automotive grade low temperature silicone an acceptable substitute or do I need to spend another $20 on the Merc product?

Secondly I was pricing gear lube and found THIS STUFF for about half the price of the Quicksilver high performance gear lube. The bottle says that it's acceptable for most sterndrive and outboard drive systems, have you heard of any problems resulting from this type of gear lube? With only 15 minutes run time on the old lube I'm planning on reusing it, but at the end of the season it would be great to cut down on costs if this gear lube is acceptable.

Thanks again!

 

[stonyloam]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

A good substitute for Perfect Seal is NAPA (Permatex) aviation sealant and it comes in small cans LOL.

That stuff is what I put into my outdrive for the last three years, including today.

 

[Leedanger]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Okay, so I have a couple of newbie questions:

First of all the manual that you posted states that I should use Quicksilver Perfect Seal to seal the gaskets when I reassemble the water pump. Is automotive grade low temperature silicone an acceptable substitute or do I need to spend another $20 on the Merc product?

Secondly I was pricing gear lube and found THIS STUFF for about half the price of the Quicksilver high performance gear lube. The bottle says that it's acceptable for most sterndrive and outboard drive systems, have you heard of any problems resulting from this type of gear lube? With only 15 minutes run time on the old lube I'm planning on reusing it, but at the end of the season it would be great to cut down on costs if this gear lube is acceptable.

Thanks again!

Wait til the end of the season before you decide to go cheap on the lube...you may just decide to spend the extra $10. Just make sure if you are using synthetic (typically its blue/green vs black) you replace it with more synthetic.

 

[stonyloam]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Wait til the end of the season before you decide to go cheap on the lube...you may just decide to spend the extra $10. Just make sure if you are using synthetic (typically its blue/green vs black) you replace it with more synthetic.

I will correct myself and agree with that, especially with a new boat, best to stick with what it came with.

 

[friendly_jacek]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Wait til the end of the season before you decide to go cheap on the lube...you may just decide to spend the extra $10. Just make sure if you are using synthetic (typically its blue/green vs black) you replace it with more synthetic.

To clarify, the high performance merc lube is not synthetic.

 

[friendly_jacek]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

This thread made me worried as I did run it dry (by mistake) recently while testing the carb rebuit. 10-20 secs I guess. Never overheated at idle speeds, but didn't try high speeds. I guess I will be buying the impeller kit again.

OP, please keep us posted on the condition of your impeller.

 

[TomB985]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

OP, please keep us posted on the condition of your impeller.

Certainly. I'll be posting pics this weekend!

 

[TomB985]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

And there they are:

This is what I saw when I removed the housing:

And finally after putting it all back together:

As far as I can tell the upper seal on the impeller was burned up but otherwise it looked pretty good. I'm not sure whether or not it was necessary to replace this season or not, but I'm glad that I know for certain that I have a good impeller. What do you guys think about this, did I replace a good impeller?

The job took me two and a half hours from start to finish with this newbie taking his time at every step.

Tomorrow I'll have to go and connect the vent tube at the front end of the outdrive that I forgot about until now, can anyone explain exactly what this thing does?

 

[Fordiesel69]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

I honestly think that impeller looked just fine. Keep as a spare in case you melt one. It is good to get you back in the water if you can;t get one fast.

 

[friendly_jacek]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

TomB985,
Thanks for the pictures. The impeller looks good indeed. Do you think the seal was burned by running dry?

I tested mine in the water today and after running the boat for several hrs, including some water skiing runs, I can tell that no overheating whatsoever. I guess 15 seconds is not enough to ruin an impeller.

 

[TomB985]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Thanks for the feedback and pictures. The impeller looks good indeed. Do you think the seal was burned by running dry?

I don't think so, the seal looked undamaged and pliable when I removed it.

Knowing what I know now I shouldn't have replaced it, but the thought of a disintegrating impeller cooking a brand new engine would have driven me crazy if I didn't make sure. A new engine would set me back over $5,000, and despite the fact that it's still under factory warranty they wouldn't cover a repair if they found a trashed impeller from water starvation.

We had it in the water today for about an hour and it performed flawlessly. Doesn't appear that I screwed it up, but I honestly am not sure how I'd know if I did. Even if one of those gaskets leaked a little it would still move lots of water, so could anything be damaged if this were to happen?

 

[Don S]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Your impeller is defective, and it needed replaced. The impeller vanes should straight out within 10 minutes, not stay bent over as in your picture. The pumps work because the impeleller vanes bend and open back up. That's how the pumps work.
Since yours don't straighten out , at higher rpm you are going to get less flow.
That is why you didn't have problems until 3500 rpm.

Just because an impeller doesn't have cracks or the blades are broken off, doesn't mean it's a good impeller. That one isn't even a good spare.

 

[friendly_jacek]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

I stand corrected. I went back and looked at the old impeller I had saved from a replacement I did several years ago and the vanes were mostly straight indeed. That old impeller also had a couple of short dry runs. I guess I forgot about the shape difference.

 

[boaterinsd]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

Dont try and save a penny (on a used impeller) when you have a huge dime at stake. IMO if you have the L/U off and wonder about the pump impeller as far as time or condition; replace it. The ENGINE has no other way to cool/ pull water up to it. I lost a good 70hp O/B because of this.

 

[Blacksting]

Re: 15 Seconds. Long enough to trash an impleller?

Re: 15 Seconds. Long enough to trash an impleller?

who wudda thunk it ? cept Don S,...............