18ft winner zz880 mach II motor too big?

[Doug Taylor]

I bought a 1987 18ft winner zz880 mach II boat and I'm thinking the motor is way to big. It has an evinrude 235hp and thinking it's too big. If it's not to big was wondering what size prop and pitch I need since it didn't have a prop on it. I checked on Iboats.com and it said the boat weighs 890 lbs but on nada.com it says 2200 lbs. Was wondering what the correct weight would be

[Wayne P.]

http://boatspecs.iboats.com/Winner__ZZ880_Mach_II__1987/bp/66b102216

Looks like the boat you are interested in is a liability nightmare.

[Doug Taylor]

On 12/7/2016 at 5:56 PM, Wayne P. said:

http://boatspecs.iboats.com/Winner__ZZ880_Mach_II__1987/bp/66b102216

Looks like the boat you are interested in is a liability nightmare.

The thing about it is the 150hp and 235hp are pretty much the same weight so don't think that's an issue. My problem is I don't wanna run down the lake at 80mph. I'd like to know where to start with prop size and pitch and max rpm on this motor. 

[Wayne P.]

1 hour ago, Doug Taylor said:

The thing about it is the 150hp and 235hp are pretty much the same weight so don't think that's an issue. My problem is I don't wanna run down the lake at 80mph. I'd like to know where to start with prop size and pitch and max rpm on this motor. 

You are correct about the motor weight is irrelevant, it's the HORSEPOWER above the hull rating--that is your liability issue---look up the definition of liability.

You prop a motor at its max rpms. Just because you may can go 80 mph does not mean you have to.

There is a throttle involved that you control.

Just a simple web search found this:

http://boatspecs.iboats.com/Evinrude__E235STLCO_2.6XP__235hp__1985/bpe/57e2352

and this:

http://www.screamandfly.com/showthread.php?143289-1982-Evinrude-235

 

[WRB]

When you exceed the boats maximum rated hp limit insurance is voided.

My guess would be  3 blade 27P SST prop would keep the rpm's Under 6,000 @70 mph.

Tom

[Way2slow]

Are you sure it's a 235 or has someone just put a 235 cowling on, that gets done all the time.  If it's is in fact a 235, the back of it will have a big hump, making it look like it's an oil pan, if it's not a 235 it will be flat.

Next, did you do a compression test on the motor.  The 235's were very prone to ring problems because the top ring was a tapered ring and was very close to the top of the piston.

As for horse power, a good 235 would be about the same as a 200 rated by todays standards, but would not have near the power of todays 200's.  As for over powered, yes, it is some.  Is it too much motor for that boat, probably not.  Years back, I had a 17' a little lighter than yours with a 235, and it peak out a 73 mph.  Just hope you know all about chine walking.

As for props, if it's a good strong, motor, probably about a 26" pitch Raker is where I would start.

Understand one thing about your setup that can actually kill you, or at a minimum, scare the total crap out of you.  It's a thing called "blow out".  If the speed does get into the lower to mid 70's, without a nosecone on the lower unit, that's about the fastest that lower unit will go without blowing out.  This will usually throw the boat into an immediate bat turn.  That's an immediate 180 @ 70+ mph, which can send you on down the lake while the boat is trying to go the opposite direction.