Mercruiser 5.7 Fresh Water Cooled : Raw Water Pump Jammed

pistole

Just to share : 

Took the 330 out yesterday with the family. This has a pair of Mercr 5.7 efi's driving Bravo3. Got to a fishing spot , dropped anchor and killed the motors. About an hour later , starboard refuses to start. Cranks but no start. Add throttle , crank and then she starts , but with a very loud shrieking sound from engine compartment. Killed that engine.

Did not want to prolong stress for family , started up port engine and limped home with that one engine. Docking with one engine when you're used to two is quite an experience (note to self).

Arranged for family's lunch at marina's cafe and then opened up the engine hatch

Long story short  , the engine could not start because the raw water pump was jammed and preventing the engine from turning over. I took off the serpentine belt and the engine started right up (killed it immediately , needed to just confirm that the problem was not with the motor).

I rotated the raw water pump's pulley by hand (it turns clockwise , by the way) and it stated to loosen/turn after some effort. I could see that it was working because the water visible through the sight-glass on the sea water strainer was churning.

I put the belt back , tensioned it and started the engine. Runs like a champ.

Has anyone experienced something like this before or could share some opinion on this. I am planning to open up that pump and have a look. Would it be likely that the impeller is destroyed ?

Thanks.

GMSLITHO

maybe a bearing in the pump 

reneechris14

X2 on the bearing maybe it got hot on the way to the fishing spot, shut off cooled down and kinda frooze up. On start up did not what to spin? Good news they do sell a rebuild kit,bearing and seal.

LaRea

Yeah, sounds like a bearing.  How hard was it to turn the pump by hand?

reneechris14

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LaRea

While you have it open, be sure to check for wear on the inside of the pump body, where the ends of the impeller rotate against the metal.  When these pumps get too much wear, they won't pump enough water to cool the engine.  You can replace the bearings, but you can't do anything about a worn pump body.

pistole

LaRea said:

Yeah, sounds like a bearing.  How hard was it to turn the pump by hand?

Hi. Wasn't very hard. The main resistance was at the start , after that it turned smoothly. 

Am getting the rebuild kit.

pistole

GMSLITHO

I did my pump this season and the pump kit is different from the one above like
 Larea mentioned my wear plate is not replaceable  

rasbury

There is a kit you can buy for100 bucks that you can put in the brass pump bodies. It has a shorter impeller and a top and bottom wear plate. Have one in mine and works fine. Better than 700 bucks for a pump that will soon wear again. We have a lot of sand to get into the pump around here!

Cableguy Greg

Same thing happened to a friend of mine with a 270. The impeller broke apart and jammed the pump. Chances are that is what happened to you.

Black_Diamond

Hardin Marine for new water pump. 

pistole

Thanks guys , will open it up and take a look. It's either the impeller or the bearings

pistole

pistole

Can't get that bolt off to release the raw water pump's bracket. Any ideas please?

And the pump cannot come out as it is trapped by the pump pulley, the pump body and the bottom of the hull.

Am almost out of ideas.

Help

reneechris14

Try one of these. I have had good luck with them.

Black_Diamond

Try. Very. Very carefully adding heat. 

aero3113

Aerokroil works well also

Kano Aerokroil Penetrating Oil, 10 oz. aerosol (AEROKROIL) https://www.amazon.com/dp/B000F09CEA/ref=cm_sw_r_cp_apu_i_UJvaBb9X20REF

GMSLITHO

Reenechris 14 thanks for posting those bolt extractors they look good to have in the tool box I just bought a set of 5 on eBay used for 20 bucks free shipping ........

reneechris14

Must keep good pressure in to get a good bite.

pistole

Ok. Will try heat first. The local boat guy recommended hammering in a smaller socket or worse case scenario to weld on a bolt.

Will look at the bolt extractor.

Thanks

pistole

reneechris14 said:

Must keep good pressure in to get a good bite.

There's almost no space to work (what's new ya) but will persevere

rasbury

I just used those bolt extractors...they worked great and used heat(maps, yellow bottle) and you cam put on an impact- may not be recommended on a camshaft however...

andyd

No kidding, that motor looks like it has been submerged in seawater for some time. Mine has been around salt water for its entire 12 years and has minimal rust, just some light surface corrosion, no pitting like that. Good luck with the bolt removal!

Andy

Black_Diamond

MAP gas as rasbury mentioned. Make sure you have the compartment super ventilated before firing up the torch!

pistole

Would the flame be applied the bolt head or the surrounding area?

aero3113

Put the flame on the bolt head. You want the heat to get to the threads and break the corrosion when it expands and then contracts when it cools.

pistole

Thank you guys. Lots of good practical suggestions. 

Was a hard day yesterday.

pistole

andyd said:

No kidding, that motor looks like it has been submerged in seawater for some time. Mine has been around salt water for its entire 12 years and has minimal rust, just some light surface corrosion, no pitting like that. Good luck with the bolt removal!

Andy

Hi. It's quite common over here is South East Asia. Salt water combined with very high humidity contributes to our situation. I have been working slowly with small wire brushes and spraying lots of lubricant

pistole

GMSLITHO

I just used this on my outdrive