Run Dry Impellers

[Cooler]

My mechanic is asking me if I want Globe Run Dry impellers in the water pumps. Has anyone used these and have an opinion? He installed some in a go fast boat three seasons ago and said they were going to change, and the old impellers looked and felt new. I know the owner he is talking about, and that guy is one of those full throttle types. I am thinking I can get multiple seasons if the impellers are what they claim they are. I did see some other users complain about them, but that was from 2011, so maybe that is old info. Thoughts? er

[Viper]

I guess the question is why bother? I too heard of problems with them and last I looked which was a few years ago they came at a premium price. Even with a premium impeller, I'd still caution against increasing the standard 2 year replacement interval. Just not worth it in my opinion. And if I'm going to stick to my 2 year interval regardless, then there's no sense paying more for an impeller. I also have no need to run the engine dry, and if I did, the impeller might survive but the exhaust hose wouldn't.

There may be some go fast guys that put off impeller replacement but all the guys I know replace them and fluids after almost every run, they just don't want to take any chances, the consequences of a failure can be way too costly. The impeller is probably the least expensive part of those engines. None of the guys I know would want to cut that corner.

[waybomb]

How often will you be getting air/jumping waves? Probably not often. So why would they run dry?

[Midnightsun]

Snake Oil comes to mind! Read the reviews, according to them they are crap. Many years ago this was the case and the same applies today. Believe me, if there was a magical impeller that was proven to outlast them all, we all would know about them and you would not be here asking the question

[Cooler]

Yea, I knew you guys would talk me back to common sense. Thanks all! er

[Metterdvm]

So, while we’re on the subject, what is the replacement interval for impellers? Last summer was my first season with a new to me 2003 356 with 8.1 Mercs. Don’t know when the impellers were replaced last. I was going to change them this winter, but when I took the port pump off, the impeller looked perfect so I left it. Did I make a mistake?

[Viper]

Source of the post .....Don’t know when the impellers were replaced last....

That's your answer! If you don't know how old they are, you need to replace them. Replacement is recommended every two years, sooner under certain circumstances like shallow boating/anchoring where you may be stirring up a lot of sand. If you don't have strainers and you're in waters with debris like weeds, etc., the same applies. Could you get longer than 2 years, a lot of people do but they're running on borrowed time, it's not worth the risk.

I never replace impellers going into/over the winter. No sense in having new impellers sit there in the same position for 6 months, You'll be starting in the Spring with impellers that already have set to them. Change them in the Spring.

[tomschauer]

If you took the pump apart, you probably should have replace the impeller anyway as the impeller really doesn't cost that much.
On the other side of the coin, when we bought our 1998 355 5 0r 6 years ago, it had impeccable service records with less than 200 hours. Near the end the first year of owner ship, the starboard engine was running a bit hotter than port. Not a big deal. When I went to winterize the boat, the starboard wouldn't pull the antifreeze. I pulled the pump (really a project for the starboard engine) and found only a fin and a half in tack! The housing, and all bolts etc, looked factory new. After reviewing all of the record a bit more closely, the port impeller had been replaced every other year, but the starboard was never replaced. It was 17? years old.

[Midnightsun]

Impellers types and application vary quite a bit mostly due to water conditions, sand/silt/salt/pollution all add premature wear.

I hear of people who remove them every fall lay up to prevent deformation, personally I do not believe in this and have never done this. In my past stern drives I normally changed every 5 years, never had an issue. I have also read of people who change them every year! I was shocked to see the impellers in the Volvo diesels were the 10 year old originals with almost 1000hrs on the clock, that being said I know they last a long time on these particular engines. I will be changing them this spring just for piece of mind although they only have around 400hrs on them. By the way, a set of spare impellers on board is a must!

That being said, it is my firm belief that winter layup with alcohol based pink stuff just kills your impeller prematurely not to mention alcohol is very corrosive. Basically you are storing your impeller/s in alcohol during the off season! Alcohol and rubber do not mix well. Use only Propylene Glycol based anti freeze, although not always clearly identified, if it's pink and does NOT have a flammable pictogram on it, you got the right stuff. Any product that shows a flammable pictogram is alcohol based and not suitable in the long term for your engine and parts of your plumbing. Unfortunately many see the pink stuff for cheap in large surface hardware stores but most of these are alcohol based. Never have I seen Propylene Glycol based anti freeze at hardware stores or Canadian Tire.

Here is an example of the good stuff. As you can see, no need to pay an arm and a legs for the right stuff either! https://www.entrepotmarinemart.com/en/a ... c-stb31200

[pepmyster]

Hans, Don't shoot me. I'm one of those guys who also that use the pink stuff. Mind you, never had a problem, (knock on wood),but can see the long term affects happening, especially for someone who is not an up to date maintenance kinda guy.
But, this coming winter, let's get through summer first, I will be changing over to the good stuff. I need to do the impellers this spring also. Points taken on the pink juice, and they all make sense. You know, you'll still get people who have their own ways .