Odd Occurence w/Sea Water pump-gctid757359

[watchthis]

I don't know that there is much to take away from my experience other than carry towing coverage, but here goes:

I had the family out on Puget Sound last Friday heading from Olympia to Brownsville. With about 3 miles remaining in our 45 mile trip and while cruising at 3400 rpms and 19 knots the engine sounded as if it had been thrown in neutral. It was the guardian system kicking in and I immediately throttled back to idle and looked at the gauges, which I always do any way. The all knowing smart-craft gauge had the temp at 190 and rising.I shut her down, dropped anchor and lifted the engine hatch and there was no visible issues with hoses,belts, fluids or leaks but damn were the risers hot. I figured my 5 month old impeller had died a violent death or I had inhaled some eel grass but i was wrong. In looking at it today, it turns out that the impeller is fine but the sea water pump shaft literally broke in half. It looks as if the shaft was simply defective and chose that time to give up the ghost. Not sure if anyone has had the pleasure of this experience, but as I said, get and keep your towing coverage. God knows it just saved me at least $2500. Do any of you replace the entire pump just based on age and hours? My Horizon 6.2 and Bravo II is from 2007 with just over 420 hours on it.

[Davidlyne]

My seawater pump was replaced 2 years ago. Didn't break but was scored and wouldn't pump correctly. Mine is a 2007 also about 500 hours last time I checked.

[Norton_Rider]

I definitely will continue my Towboat US membership. For many years I never needed them. Then my previous boat had two failures within a few months of each other. The two tows that I got would have cost many times what my membership had cost until then.

BTW, I know that many insurance policies have towing coverage. I personally prefer a Towboat US membership. You get towed with no questions asked, with no billing or reimbursement hassles.

[MonteVista]

My seawater pump (Sherwood 105) had a catastrophic failure as I was sailing between Greek Islands Patmos and Arki. My temp gauge normally shows 175F but for the past couple outings it showed about 190F when on the plane and would drop to under 175 when I came off plane. So, I was keeping an eye on things but everything looked normal. I had the engine serviced at the beginning of the season and replaced the impeller. Anyway, suddenly, the engine put itself into protective mode, and I pulled the handle back. Within a minute the temperature dropped to under 175F. When I looked at the engine I could see that water was spraying out from under the seawter pump and was being sent all over the place with the spinning belt. I checked and did not find any hose issues. So, I covered the batteries and the charger/inverter with a plastic sheet to protect them and limped back into Patmos. As I was cruising overseas and did not know any locals I called the agency that helped me with my entry into Greece and asked them to find me a mechanic. The mechanic was an excellent guy, very skilled and had a very good workshop and was the Mercruiser dealer on the island. He checked and found that that pump did not exist anywhere in Greece, needed to be flown in from Brussels, European HQ for Mercury. ALL in all it would take about 1 week for it to be received locally and installed on my boat. Parts cost was 1000 Eur ($1100) plus tax, plus mechanic's fees. He opened the pump and said he had never seen a failure this bad. One of the ball bearings was completely gone, casing broken in two, balls gone (I found a few in the bilge). The shaft was scoured a bit and he did his best to smoothen it so new ball bearings and seals could be pres-fitted on it and not leak. The repaired pump seems to be working and I was able to return to my home port and had yet another outing with the boat. When he connected the diagnostic computer to my engine and looked at the failure record, engine coolant heat had reached 104.2 C (220 F)!

By the way, with his advice, I ordered a new pump nor from Mercury but used thenSherwood part number and found the pump at a marine parts score, for half the price. I Shall install the new pump and keep the repaired pump as a spare.

[Guest]

I carry so many extra parts on board, starter, alternator, ignition module, impellor kit, cap, rotor, spark plugs, fuses, wire, alligator clips/wires, and so on. Plus I have a 10 HP trolling motor.

Wouldn't you know it several years ago I suck up a plastic bag against the drive and the pump runs dry, the impellor grabs the "cam" inside the pump breaking it's screw off that retains it to the housing.

The cam then spins in the housing until it lodges up against the remains of the screw which happened to also stop the cam over the pumps output hydro locking the pump, blowing out the rear seal and cover gasket, and splitting the impellor in half.

I had every part I needed onboard to fix it except the stupid single M5x0.8 metric screw to retain the cam in the water pump housing and therefore I have to go home on the kicker. Running against the tide most of the way it's slow going and using up the kickers 3 gallons of fuel quickly, so I tie up to a mooring buoy, remove the + wire from my coil, remove the fuel line banjo fitting from the carb, and use my alligator clip wire to hotwire the starter to turn the engine over to pump fuel into a empty Gatorade bottle then dump it into the kicker tank!

7 hours later I'm finally back at the launch! The next day I buy one 10 CENT stainless screw and I'm back in business.

[Chief_Alen]

Get rid of the oem pump, and mount one of there crank mounted pumps ....

http://inetmarine.com/crankmountedpumpsandkits.aspx

[watchthis]

Chief, can you tell me the benefits of the crank mounted pump?

[Chief_Alen]

Easy peasy to change out the impeller, and my favorite price.

I'm on the iPad right now do a search of this site, you will see what I'm talking about.

[sbengtson]

Went through 3 mercruiser seawater pumps on my boat. All lasted about 300hrs. and then toast. Bearings rusted out and all kinds of bad stuff. My savior was my kicker motor coming in 25 miles off the CA coast at 5mph. Good weather, easy trip, except it took a long time. So, after the third time I re-read the guys posts on putting in the crankshaft model and it is a winner all the way around. With the Mercruiser pump it would take an hour or more to change due to position and cramped quarters, never could do that on the water. I always had to replace the whole thing, which gets expensive. The switch over was one of the best things I've done on my boat. It is east to change impeller or the whole unit. It is half the cost. It has lasted longer. Now, I run in saltwater most of the time about 400 hours a year, You can probably do better on time with the merc pump in freshwater. This is with a full closed cooling system, mpi 5.0 bravo 3. It cools great didn't need an extra hole in my boat. Uses existing plumbing from drive Just search and you'll see the basics for the conversion. As always you might have to adapt like find the correct size belt since the merc. pump is out of the system.This is a huge thanks to the guys that figured it out and put some of us on the right track. I have been truly grateful for the advice and it can save you a lot of trouble.