Look at these 8.1 440HP rebuilds...

M

mrsrobinson

Well-Known Member
Mar 9, 2006
7,704
Virginia
Boat Info
2001 380DA
Engines
Caterpillar 3126
Maxum's were on my short list of new to me boats in my last few searches. I looked at a couple of 3700/4100s. Fit and finish was not for me though. Because I have nothing better to do I left the searches turned on. This one showed up recently:

https://www.yachtworld.com/yacht/2001-maxum-3700-scr-8521258/

Take a look at those
  • Completely rebuilt MerCruiser Horizon V8 8.1L 440HP gas engines with new manifolds and risers and hosing with only 40 hrs!
Is it me or are those 7.4s?

I do like the black hull wrap with the siler accents though.
 
Yeah. 7.4 Horizons subject to water reversion back in those days.
 
454 Mags. No doubt about it. How do you expect to get top dollar for a boat when you don't even know what's on it?!

First boat was a 2800 SCR with a single 7.4 and B3 out drive. Great starter Boat.
 
bfernald0 said:
454 Mags. No doubt about it. How do you expect to get top dollar for a boat when you don't even know what's on it?!

First boat was a 2800 SCR with a single 7.4 and B3 out drive. Great starter Boat.
Click to expand...
Agreed, I blame the seller as they should proof/read the brokers ad.

My first 2 boats were Maxums, I was happy with them.
 
I'd buy a maxim before a Bayliner
 
440hp out of 7.4 would be a serious exhaust reversion concern. Are there dyno sheets that confirm the hp claims? I had my 454s rebuild 9 years ago with a "mild" camshaft that dyno'd at 380hp. The shop owner consulated with comp cams and the would not go any more aggressive. 9 years later they run strong with no signs of reversion.
 
Don't forget a 396 made 375 horse back in 1969. With technology 440 isn't much
 
Scott215 said:
Don't forget a 396 made 375 horse back in 1969. With technology 440 isn't much
Click to expand...
Marine engines are a whole different story. Generally the changes that make big horsepower also increase the chance of reversion.

Not a bad thing for a street engine with dry exhaust, but it’s a death sentence for a marine engine with water cooled exhaust.
 
Is that because of cam lift , duration. Lobe separation angle ect
 
I’m no expert but I think overlap is the issue. The brief time that both valves are open at the transition from exhaust stroke to intake stroke.
 
Black hull? No thank you. Not sure why big displacement blocks would need a rebuild. They leave out what hours they had prior to rebuild and why it needed a rebuild. Also, what do them mean by a "rebuild" exactly. I have a 1981 350/260hp completely original with almost perfect compression across all 8 cylinders.

Nice boat though.
 
El captain that's great how to take care of it well
 
Even though it's off the subject and easy way to get horsepower is compression and a good set of cylinder heads
 
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