Impeller looks bad

[Download7]

Hi everyone

I'm looking at the impeller for the first time since buying the boat last year and all I can think is thank god it didn't blow up...or maybe it's supposed to look like that? Specifically the odd shaped hole, is that normal? I can't tell if it's growth or should it be like that? Should I just try and clean it out at this point or look at replacing it?


It's a 1985 Beneteau first 435 with a Perkins 4108


It rotated the pictures I'm not sure why but the inlet/outlet go to the right.

[Mike OReilly]

I’m far from the most experienced engine guy here (very far ), but I have a 4108 with what looks like the same pump. And I’ve changed my impeller a few times.

Yours doesn’t look bad to me. Looks pretty normal, except for what appears to be like some sealant, or old gasket material, squeezed into the chamber — hard to say for sure.

I’d pull the impeller out clean that stuff off. Be careful not to score the pump. Then, look at the spines of the impeller. If there’s any cracking, or if they feel stiff or brittle, then definitely change it. Heck, I’d probably change it anyway now that you’ve got the thing opened up. But from your pic I don’t see anything obviously wrong.

Maybe more experienced folk will have a different take.

[Lepke]

Looks normal. Odd shaped hole, I assume you're talking about the inside housing, is shaped that way to compress the vanes. When the space between the vanes opens it draws water in and when the space compresses it forces water out. Take out the impeller and inspect it. If the vanes are cracked, brittle or hard, it needs to be replaced. When installing, wipe out the inside housing and cover plate. Lightly grease with waterproof grease. The grease helps the first start by increasing suction and protecting the vanes from over heat until water arrives. Friction heat is a killer for vanes. I have a 4108 generator and the impeller lasts over 500 hours, but I inspect once or twice a year and regrease.

[boatman61]

Take it out and throw it away.. after taking it to the store to get a new one.. the centre should not look like that its shot.. there should be a metal or other rigid centre.
Clean the housing then fit in the new one and fit a new gasket for the cover.
They're cheap enough and well worth the saving of hassle if it disintegrates and sends bits into your system.

[gaucho]

That not circular shape is perfectly normal on most engine water pumps. That yellowish material could be like Mike said, some gasketing excess material. If you are going to change the impeller (which I would since you got it opened), make sure you really clean the surface of the cover as well as the surface of the pump. I would use a blue scotch brite pad, or even a green if that won't get all that yucky gasketing material off. When you replace the cover, make sure that the odd shaped place where the impeller twists should be sort of "marked" on the cover too.

Don't worry about which way the blades are in that portion. They will find the proper routing once you get that pump going. When inserting the new impeller, remember to use some liquid hand soap to help lubricate and make the job of inserting the impeller easier, but also as a way to lubricate the impeller while it gets sea water inside the pump when priming.

Please get an impeller puller! So many people try to pry the impellers with pliers and end up damaging the bronze on the pump, etc. Do yourself a favor and get the right tool for the job. You will need to pull that impeller once a year or every two years anyhow, so it will be a worthwhile investment:

https://www.amazon.com/Sea-Dog-66004.../dp/B002FVKBSI

Or maybe check maybe there is one in your boat already.

Also, I always apply just a bit of grease on the interior of the impeller (or on the shaft where the impeller goes) when putting it back together.

[DougR]

That impeller is toast. The end looks like it got hot and partially melted, and if you enlarge the photo, you can see that several of the blades are showing cracks where they attach to the hub. Time to can it....

Buy two new ones, one for the pump and one spare. Don't use grease when you install the new impeller in the pump body, it's hard on the impeller. But a dab of waterproof grease on the shaft won't hurt. Most pump suppliers ( Yanmar, Volvo, Johnson, Jabsco, etc) recommend glycerine instead and supply a small packet with the new impeller. Or you could use liquid dish soap in a pinch.

DougR

[Download7]

Thank you everybody for the help/ tips/ info. I'll get a couple new ones and put one in with some waterproof grease and new gasket

[a64pilot]

Do not use grease, it may eat up the impeller, use dish washing liquid or glycerine, or even “personal” lubricant that is safe for a condom, reason is the same.
Sometimes impellers will come with a packet of lube, mine never have, but some do.

[boatman61]

Originally Posted by Download7

Hi everyone

I'm looking at the impeller for the first time since buying the boat last year and all I can think is thank god it didn't blow up...or maybe it's supposed to look like that? Specifically the odd shaped hole, is that normal? I can't tell if it's growth or should it be like that? Should I just try and clean it out at this point or look at replacing it?


It's a 1985 Beneteau first 435 with a Perkins 4108


It rotated the pictures I'm not sure why but the inlet/outlet go to the right.

There should be a number somewhere on the pump.. usually its on the front of the cover plate under any paint so scrape off carefully its easily scored.. but if not check the pump body.
This number and the pump make will identify the impellor you need as opposed to a 'this will do'.. pump is likely a Jabsco.. heres my link to a supplier.
https://www.asap-supplies.com/pumps/...co-pump-spares

[Download7]

Ok I get it thank you

[Bleemus]

What Mike O Reilly said. Get a new impeller and clean it up getting rid of that "yellow" stuff whatever it is. Just don't scratch the inside of the pump.

[oztayls]

Whilst this thread is "sorted", I just thought I'd put this up to help folks looking up this thread down the track. It's a good diagram of the basic principles of how this type of pump works.

[Wetterbote]

Just make sure to install the new impeller the right way (with the blades looking the same direction as before). Otherwise, it will break very quickly.

[Searles]

Get a run dry impeller worth every cent.⛵️⚓️

[Tetepare]

Originally Posted by gaucho

That not circular shape is perfectly normal on most engine water pumps.

Tell me more. My oberdorfer didn't have that "insert". And if our current pump does, I didn't notice it. I've helped others change impellers on a variety of boats, and don't ever recall seeing that. Intrigued.

I can understand some fluid dynamic reasons to have such a compression, but darn that looks like it seriously compresses the impeller, to the point I'd expect early failure.