Fuel Pump Replacement

[brineair]

Hi all. I have to replace my electronic fuel pump on my 2001 Mercruiser 5.7 Bravo III close cooled engine. Seems easy enough, however there are a lot of obstacles in the way that need to be moved before I can take it in and out easily.

The first obstacle is the hose going up into the coolant system. I tried loosening it and taking it off but red liquid started trickling out. I'm assuming that was anti freeze. Not sure why it would be that though as I've ran it multiple times this year at length. Wouldn't that get rid of any antifreeze in the system? Regardless is there a drain on this that I can drain all of that out of into a pan and save to put back later? If I can get this main hose out of the way I should be ok. There is another smaller hose But I think I can work around that.

Has anyone had any experience with this? Thanks for your help.

[mmwjr]

Closed cooling, so why do you think the anti-freeze would be gone? If so you have another issue.

Closed cooling is like having a radiator in a car. It sounds like the host you are refering too is coming off the engine circulating pump and to the heat exchanger.

There should be a drain on the side of the engine. Also the hose you mention may have a drain at its bottom.

If the antifreeze has never been changed then I would do it now.

[brineair]

Mike,

Thanks for the response. I don't know much about engines but figured I'm mechanically inclined enough to hopefully replace this fuel pump with a little info and time. So thank you for any help again!

As far as the antifreeze being changed I had it winterized at the end of the season last year. So it is changed once a year.

I have attached a picture where I circled what I believe is the closed cooled system with the hose that needs to be removed to the bottom left. I will look for the draining plugs but by looking at this picture does it give you any better idea? The fuel pump is directly behind that hose. Thanks again!

[mmwjr]

Since the closed cooling system contain antifreeze just like you cars radiator it does not get changed as part of the winterization process.

There is old antifreeze in there.

There is a an open (raw water) part of the cooling that goes through a raw water pump, power steering cooler, heat exchanger, exhaust manifolds and elbows.

When winterizing this open system is what they run antifreeze through to protect the system. This gets flushed out when starting in the spring.

In the picture you provided the cylinder across the top is the heat exchanger. The hose is the one I mentioned that connects from the engine circulating pump to heat exchanger. Looking at the picture the bottom of the hose has a drain plug.

[brineair]

Mike,

Thank you again for answering my question. It seems as though it's only you and maybe one other person or two that answer questions on these forums. So again your time and info is greatly appreciated!

I spoke to a mechanic from the local Marina I purchased the boat from. I told him I have to take that hose off the get to the fuel pump and replace it, but needed to get rid of the coolant in the cylinder.

He said to remove the hose or use a drain plug and catch as much as you can with a pan. He said it would be hard to get it all. If it got down into the bilge it is ok as it is marine grade dex cooled antifreeze.

Once emptied enough remove hose and complete the fuel pump install. Then pour new antifreeze into the system (will need to add correct water amount), put cap back on then run it for a while (10+ min). Open cap back up and check that the level didn't go down. If so refill to fill line, put cap back on and your good.

Does this all sound about right? Thanks again!

[speedysprocket]

That's the biggest hose in the whole system and it's at the lowest point. You need to be prepared to lose almost all of your coolant. I wouldn't try collecting it to reuse. Just put fresh stuff in.

[mmwjr]

Yes what the mechanic said is correct.

I would not reuse the coolant.

You can buy premixed coolant so no need to add water or if you buy the full strength mix it 50/50 with water.

[brineair]

Mike & Speedy,

Thanks for the info. I will definitely be putting all new coolant in. Thanks again for all your help. I will give updates as I progress. Thanks again!

[brineair]

Hey guys just wanted to update everyone that may be interested in this thread. I was able to successfully replace the fuel pump and get the boat running again. Hardest part was removing the main coolant hose to make room to get to the pump. Unfortunately I wasn't able to find the drain plug for the coolant. It was not at the bottom of that main (largest) hose, at least from what I could see and feel for. However it drained about 1.5 gallons, which I replenished after the install with new coolant.

I did also replace the fuel filter. I was told when I do that I am supposed to run a bit of gasoline around the new gasket to help seal it, so I did. I didn't however refill it with gas as it would refill once the engine started. Come to find out it probably would have helped it start up quicker as we had to pour a little bit of gas down the carburetor. Once we did that it fired right up.

Thank again for everyone's help!

[mmwjr]

Glad to hear you are up and running, now enjoy the rest of the season.

[danaoverman]

Do you know the Part # for the fuel pump?

[sph801]

I replaced a fuel pump on my Mercruiser 5.7 with carburators. The P/N was 861155A 3


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