Here's a better look at the 'black thing'

 

That's is indeed a check valve. As for your symptoms, I would doubt you have a clog anywhere in the system. My guess would be a worm impeller.

dusty ~

 

Thanks for the input... and that's what I keep hearing

 

Bravo III and 2's also have a issue where the sea water hose passes thru the outer transom plate. The hose gets crimped down from corrosion on the outside of the hose.

It is an easy check, just remove the 2 bolts that hold the plastic barbed hose fitting on the transom plate and see if the hose is not squashed down. The outter hose terminates just behind the plastic fitting.

A sure fix is to change to "thru the hull" cooling. Mercrusier make a kit to achieve this. Once done, you get a much better water flow.

 

I am assuming you have Smartcraft gauges on your boat. If so have you checked the water pressure? If your impeller is worn you will see that you do not have adequate water pressure by looking at the pressure reading in the LED window of your gauge. On my engine the water pressure is about 1.5 PSI at idle and around 10 PSI at cruising speed.

Dave

 

Your temps are confusing me. Am I missing something? Your temps should be in the 160-175 degree range when running. Your idle temp on an EFI motor is suppoed to be 160 degrees. You need to run a thermostst with that motor. It is designed to run at a specified temp due to the computer.

Hitting over 120 degrees without an thermostst is also expected. Your in Florida where the water is probably 85 degrees. 120+ degrees is nothing, and is actually to low. Your 120+ temps sound perfectly normal to me in the warm water your in and running without a thermostat. (put one in!)

As for the impellor, change it if your in doubt. It's an easy change and worth knowing that it is good.

 

OK,

Thermostat is back in (new one) and the impeller replaced (see pic below) and still no joy.

Going to look later at the 'crushed transom hose' issue later as the tech that replaced the impeller said that's the next thing he would look at as there wasn't enough water getting to the SW pump.

For those of you that went the thru-hull intake path, what kind of rough figures did you have for the cost of the kit and installation? Also, what kind of labor is involved with fixing the crushed hose scenario? Amazing that's not a recall type of item from faulty engineering



Thanks again everyone!

 

OK, with the Merc Kit, there is not much to it. Just a metal plate and a gasket with a printed sheet of instructions.

Basically, all you need to do is remove the plastic hose fitting and place a solid gasket under it to blank off the hose, and then put the hose fitting back, tighten up the 2 bolts.

The most important part of this proceedure is to cut away a section of the hose between the transom plate and the top gear box. This allows water to be forced into the intake on the leg and up thru the water passages to cool the gear box. If you leave the hose intact and blanked off, you will have no cooling.

The next step is to install a bronze skin fitting, 1.25", designed as a scoop with a grate on the leading edge.

Inside the boat you'll need a ball valve, bronze with SS ball, and a hose fitting and a length of 1.25" hose that won't collapse under vacuum. The hose runs from the ball valve to the inlet of your raw water pump.

On top of the ball valve, I installed a "Tee" with a garden hose fitting so I can flush out the system with fresh water. To do that, you will need an extra ball valve.

Here is a picture when the motor was out, the skin fitting is on the starboard side just aft of the engine mount. You can see the yellow handle on the ball valve under the red starter cables.
The hose fitting for the engine is aft and forhead is the extra ball valve and the garden hose fitting.

Here is a picture of the outer transom plate showing the plastic hose fitting on the right side of the picture.

Hope all this helps !

 

Congrats to the call on the blocked/pinched water neck being the culprit!

That's just piss poor engineering in my humble opinion

 

That's good we've have found that one. :thumbsup:

You can see why I went for the "Thru Hull cooling".

The 1.25" hose is miles better than that thing that comes thru the transom, I think it's only about 5/8" inside diameter. :smt013

 

Agreed, unfortunately in my boat (2006 220 sundeck), theres really not enough room to get a pickup low in the bilge due to the engine block size. We looked at the pricing for a flush-mounted transom pick up option as well, but the price for the kit, installation, and a flush kit were almost double just fixing this engineering marvel from the factory

Dealer told me here in FL they've seen about a dozen of these in the past year already and that up until a few years ago, this water neck design was more of a hard plastic fitting that passed thru the transom and the hose attached to barbed tips on either side. But some genius decided to make the hose pass through the transom directly and put bare aluminum around it while it's sandwiched between to steel plates... if they wont recall this design, I think I should be allowed one good thumping on the head of the person that approved this change and get my $900 worth :smt021