Overheating during flushing...anyone wanna wade in?

[DJ13]

OK, this might be a simple fix, but it's new to me. Ran my 22ZX all weekend Fri-Sun, without a hitch, save a broken seat base, and came into a problem right after we pulled her out of the salt. I was attempting to flush the engine but quickly realized that the water I was feeding to the Bravo 1 wasn't making it into the engine, causing me to quickly trigger the overheat alarm. I have a 7.4L MPI, bravo 1, raw water cooled, and I'm using the orange hose/drive fluah adapter. I need to know if this could be an obstruction like seaweed, sucked into my drive as I pulled up to the launch, or if it might be a water circulation pump problem. I don't know how to diagnose which. Running all three days I never had a temp problem!! :angryfire I've received neighborly advice from non-boating neighbors but I'd rather query the vast knowledge of the collective registry. :frown: Thanks in advance for any worthy advice!!

[Greg K]

Most likely is the seaweed. I believe you'll have to get access to the pump and or hoses to get rid of it. Check the condition of the impeller as well and replace if needed.

[MOP]

Also check the oil cooler, that is the first thing to plug up. Most ramps have a bunch of floating junk that you can suck up. Theasiest way to clear the cooler is to remove the drive water supply hose the take the hose loose from the engine and back flush the cooler IE: drive the junk back out the way it came in.

Phil

[DJ13]

Greg: The only impeller I'm aware of is inside the water circulation pump. Any others anywhere else that I don't know of? Nothing in the drive, right? My understanding is that it is just suction from the circ pump drawing water through the drive and into the engine, but I want to be sure of that. A week ago I noticed a small drip coming from the bottom of the water pump but was told not to worry about it too much. Now I'm thinking that may have been bad advice...

Phil: I'm going to have to search for the oil cooler and try your method as well. I'm new to marine engines, learning something each time I go out or come in!

Thanks for taking the time to respond! I've got to get this done this morning.

[MOP]

I think you have a Bravo drive, with that setup there is a belt driven sea water pump with fair sized hoses going to it up at the front of the engine. If it is an Alpha the sea water pump is in the drive both have oil coolers, either way if you were running all day and everything temp wise was fine I think it is a blockage problem. If you have grassy weed check the oil cooler it is a metal can about 8 inches long in the line from the drive, like I mentioned before take the hose off going to the transom. Then take the hose of at the pump put a garden hose in with a rag around and back flush the cooler if a bunch of junk comes out that should fix your problem. If nothing but clean water comes out try back flushing the drive, if you get no junk out of the drive then I would suspect the sea water pump.

Phil

[DJ13]

Yes, it's a Bravo1. I found the oil cooler and sea pump. Basically, it sounds like I need to do three things:

1st: Back flush the oil cooler by disconnecting the hose from the cooler at the rear of the engine (backflush input) and disconnect the input hose (backflush output) at the oil cooler and watch for gunk.

2nd: Take the sea pump off and inspect. Replace impeller if necessary.

3rd: Replace water circ pump asap.

Looks like my work is cut out for me! Thanks again for the input! This board has saved me $$ already!! :yes:

[MOP]

First see if you have junk in the system, after you flush it out try the muffs first see if it pumps OK. If not then check the sea water pump, I doubt very seriously if the circ pump has died. With an external pump the circ pump and be removed and replaced by a T water manifold, which is about the same price and eliminates one possible failure item. Take it slow it is less expensive than crashing head long into things.

Phil

[gcarter]

When you fix it, add a strainer.

[Bryan Tuvell 33ZX]

DJ13
FIRST, pull the hose from the sea water pump to the transom, check for crap. Clear, proceed as wrote below.
Then get an impellor kit, you can either just buy the impellor ($20) or buy the whole kit ($75), if your goin into it I would do the kit, piece a cake, I am a no wrench turning mofo, I can do it, did it many times.
If you just buy the impellor, ensure there are no grooves inside the case/housing, if so replace, and be a betting man I bet there is.
see this link for how to:
http://www.speedwake.com/upload/showthread.php?s=&threadid=18967
Good luck.
Bryan

[Moody Blu']

When you fix it, add a strainer.
thats the best advice, I second that.

ever clog up a block? :bawling: not fun. :idea:

[Audiofn]

Before you start ripping your motor apart is it possible that the water preasure/flow at your hose is low? I have this same problem when I try and flush at my shop, but when I do it at home it is fine.

Jon

[Audiofn]

or even a kink in the hose.

[MOP]

All this pump replacement talk is making me give up another one of my tricks!

Get a 5 gallon container semi clear plastic so you can see the water level inside, make up a short hose 4-5 foot to connect to your muffs. Fill with water and mark the container at 1 gallon increments, angle cut the end of the hose this will keep it from sucking up against the container cutting off the flow, put the hose in make sure it is near the bottom, tie or tape if necessary. Start the engine don't worry the pump will suck the water and not harm its self, if it does not suck change the pump out. Now and watch how much water is being consumed and time it, if you do this with a new pump you can check your pump simply anytime you have any doubt and have a timed reference! You and all your buddies can check theirs pumps very easily anytime they wish.

P.S. An average V8 engine will pump approximately 1.5 gallons a minute at 750 RPM, this will vary some with pump style and pulley size, so it is good to have reference point.

Important this test should be repeated in a slightly different manor, remove the outlet hose at the pump going to the engine route it over the side into a container marked similar to the other container to be able to time the flow again. You will see an increase of about 10% this is normal. The reason for this test is to see just how much blockage your risers or corroded thermostat housing outlets may have.

Proper testing takes little time and it beats the hell out ripping things apart only to find out they are or are not bad. Try to find the cause before you end up doing unnecessary work or possibly creating another problem!

[gcarter]

Another area to look for trash is power steering and/ or oil coolers. Been there, done that. Hard to remove and clean. :bawling: :bonk:

[DJ13]

These are great tips and tricks. I really appreciate all the thoughts. This board is an incredible resource and I have to say I'd be lost without it. Thanks!!

Sea strainers: I need to get more info on those as I don't even know what they look like or where to install them.

I haven't tore much apart except for the hose going to the oil cooler, then realized the flow of the water must come from the other direction. There was nothing hung up on the screen I could see, so I'll disconnect the hose from the other side, near the transom, and try to flush through the cooler and out that end of the hose.

I will also, if I can get to the sea pump :frown: , take those hoses off and look for crap and impeller problems. Looks like my fuel filter is in the way though and may make it a more difficult job.

This is just great for my neighbor who always goes out of his way to comment on the negatives of boat ownership whenever I'm out working on my boat...which happens to be frequently. He sure wants a ride whenever it's hot though. Haven't got around to giving him one for some reason. Wonder if he's put that together with his witty banter yet.