Hydrolocking 454 mercruiser

[cruisersveesport]

I have a 26 ft cruisers vee sport 1987 454 mercruiser I/O Bravo 1 drive

I have a problem when I am out the boat hydrolocks. I had a previous post when I lost my engine and was told to use riser extensions. The problem with this is a 3" extension puts me through my floor boards.

I have no problem when the boat sits in the dock only when I am out with weight in the stern fishing and the boat bobs up and down. I am wondering would Idling all day hurt the engine? This seems to be my only solution.

Als what tempature should the boat run at? I am showing only a 140-150 degree reading. Would this prevent the boat from running properly? Especially at higher speeds?

 

[eriediver]

Re: Hydrolocking 454 mercruiser

First thing is replace the flappers. (&if you've hydrolocked at all, check & flush your oil)
2nd, get a trolling motor. Those (big engines) aren't good for trolling.

 

[Reel Poor]

Re: Hydrolocking 454 mercruiser

With the boat in the water, at rest, and a full load measure at the transom
(A) from the water line up to the top of the transon
(B) from the top of the riser to the top of the transom

Then subtract (B) from (A), if the answer is less than 13 inches you need riser spacers, or a lighter load. Be sure to check you flappers and make sure they are working.

 

[Don S]

Re: Hydrolocking 454 mercruiser

The flappers will not prevent water from coming in if you have too much weight in the back of the boat.

 

[cruisersveesport]

Re: Hydrolocking 454 mercruiser

how easy is it to replace these flappers and can it be done with the boat in the water. i never carry more than 4 people

 

[Don S]

Re: Hydrolocking 454 mercruiser

The number of people is only a part of the equation. How much other weight do you have on the back of the boat? A kicker? Dingy? Cooler? water in the bilge, fishing weightes? It all adds up.
Do the measurement.
Like I said if this happens when the boat is just sitting, even brand new flappers aren't water tight. They just keep MOST of a big waves from going up the exhaust, just kind of slows it down.

 

[whywhyzed]

Re: Hydrolocking 454 mercruiser

The Veesport is a hull that came with twin V8 5.7`s - so I can`t see weight being the only problem when you have a single screw.
I had the 454 in my 81 Veesport- never had a hydrolock problem - I idled through the trent severn waterway at no wake speed all the time. I had the TR drive however, not Bravo.

Maybe your riser to manifold joints are leaking or the manifolds are failing and the sloshing is aggravating the symptoms or something.

160 degrees would be better, but I wouldn`t worry about 150 too much - verify it with a hand held infrared thermometer or even use a K type thermocouple temp probe that comes with a lot of cheapie multimeters - press the end tight to the thermostat housing for a full minute or two.