$4000 later

[wotan2525]

The thing most boat shops won't even work on this boat for me. I called and explained 1986 Supra with 460 engine and they said that it's too old. Omaha Marine that is. FYI this mechanic took the boat out twice last week and it did the same thing it does with me. If you are flying around the lake it stays at 150-175. Then when you slow down it goes to 220 and it stays there! When the boat is running and you pull the hoses off where they go into the motor (where thermostat was) water is flowing. FYI CJD he has taken I think most the engine apart and the heads were the most warped heads the machine shop had ever seen. Those were grinded down and supposedly just fine now so that is not the issue. I'm all for calling this guy out, but how can he not know anything when he owns a boat shop over 50 boats there. Plus he's fixed our Sea Ray multiple times in the last 8 years with no issues and decent rates... I should post my bills on here shortly to show what you guys have all done.

I'm still sticking by the absolute first thing that I said in this thread. The raw water pump is worn and is not pumping enough volume at low RPMs. There is a rebuild procedure for this pump.

BUT -- if this guy has 50 boats in his yard, he has another pump around that will bolt up and allow him to test this theory. Your issue is flow at low RPMs. This is a bad pump or slipping belt. Your first post says that the RWP is new. Have we confirmed/verified that?

[Jetlink]

To add to Wotan, how much more $$$ and parts are you going to throw at this before checking the raw water pump? A new one costs way less than $4,000 I can assure you that. What you are describing as well as the mechanic that it only starts to overheat at low power settings screams to me that the issue is a flow issue. Check the pumps, hell, throw a new one on there and see what that does. If it fixes the problem, that is a win. If it doesn't, having an extra pump laying around is not necessarily bad either.

[Awill10291]

He's really busy now with winterizing and asked me to get on her or online and find a bravo pump, and I am gonna corner him to try to make sure he'll pay for it. He already said he would install for free and not charge anything. So does anyone have a website for a ford 460 (he called it a bravo pump) raw water pump that would push enough water through?? Rather than bashing him anymore I'm to the point where he is going to make this thing work with no more labor fees. I will go there in person until it's done. It's 4 blocks from my house and he works on half the boats on this lake. WOTAN, you just mentioned the belts? He said something about having trouble with the homemade brackets on the existing water pump and how when the boat runs they move and are really ghetto. I know this whole raw water pump deal should've been the first thing he should've replace imo too. Could've sworn he said he did replace it, but maybe not. I can't find all my invoices, but i'll try to post the last one.

[Awill10291]

[wotan2525]

Those images look too small to decipher.

Here's my advice (you are welcome to continue to ignore it of course) -- ask him for a part number on the pump he wants to use. Make him make the decisions and tell you what to buy. He's the expert (*cough*)

A "bravo" pump is probably driven off the crank and I doubt you have room for that on your engine. That is why the raw water pumps for inboards are mounted on a bracket and driven off of a belt. Any chance you can go down there and take some photos? I'm very familiar with 460 engines but not familiar with the marine application for them. At $4000 in you could have easily swapped in an EFI big block engine at this point.

[CJD]

From what I am reading, it was a bad temp sender. So you're fixed, right??!

[Wulphie]

This is the pump the mechanic is referring to. These do pump significantly more water than what you would find on a pcm engine. If that will solve the problem is debatable. . . http://www.ebay.com/itm/OEM-MerCruis...-/400155601291

[Jetlink]

This is the pump the mechanic is referring to. These do pump significantly more water than what you would find on a pcm engine. If that will solve the problem is debatable. . . http://www.ebay.com/itm/OEM-MerCruis...-/400155601291

Because it doesn't say that it is for a 460, hence the fabrication work required on the brackets. I agree with Wotan, some pictures of the existing pump and engine as a whole might help here. Also, make the mechanic specify the exact part number(s) he needs for this fix and go from there. Otherwise, anything else is just a shot in the dark at this point.

[Cusefan78]

You don't need a bravo pump. Get a new Sherwood pump. Supra and most inboard companies have used the same pump for every engine hp for years. Let me repeat myself. These pumps we all use will suck up a 5 gallon bucket of water in minutes at idle. If that's isn't enough to cool an engine then I don't know what will. This guy may have 50 boats he's working on but how many of them are inboards. Inboards have a different setup and clearly this guy doesn't know inboards. Get a new Sherwood pump have him out it on and be done with this nightmare.

[cadunkle]

If you did all this yourself you'd likely have spent under a grand. Most of it is fairly straightforward on these old simple boats. Anyhow, that Mercruiser pump seems pricey and a bit over the top with the external/second fuel pump mounting. I would see about whatever Sherwood pump PCM used on the 454 as I think that's closer to $300 and is plenty of flow for a 300-400 HP big block. You may have to modify brackets from something else and make some spacers to get belts to line up, but that shouldn't be too difficult.

Also, suggest you make sure starter/alternator/fuel pump/carb are all suitable for marine use. I'm paranoid about stuff like that. Automotive fuel and sparky parts are risky in an enclosed engine compartment.