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Charger 18
01-06-2003, 07:15 PM
I've got a 14X23 Thru Hub Cleaver Prop that has been slightly tweeked on my 1980 200HP Merc. The 200 is mounted on a 1982 18Foot Charger Pad V-bottom. I don't have a nose cone, vertical lift or any set back. Top speed right now is 64MPH, but I have to give it all the trim I can just before the motor cavitates to get this speed. Should I be shopping for a new prop because the motor is too old to have any aftermarket work done to it(Low water pickup, ect.)
Thanks for any suggestions devil

CrazyHippy
01-06-2003, 10:03 PM
What kinda RPM are you turning up to??
I have a 97 200 efi (different animal i know) and i turn a 24" trophy plus 4 to the rev limiter at 6100rpm. This is on a 21' pad boat.
BJH

Skaterfast
01-07-2003, 12:00 AM
If you are using excesive trim it needs set back.Start by getting a set back with hydraulic or mechanical lift like a Land and Sea.I would think you could pick up 5 or more mph by getting closer to neutral trim and the prop shaft even with the bottom of the boat.

HavasuDreamin'
01-07-2003, 07:00 AM
First and foremost, you have the wrong prop. A V-Bottom needs a chopper, not a cleaver prop. This in and of itself will reduce the amount of positive trim you need. I would buy a Mazco RE-3 which is an over the hub prop, not thru hub. This is the first thing you need to do.
As Skaterfast said, another way to reduce the amount of positive trim is to add more set back. I would say a 6" setback combined with a 6" Jack Plate would be about right (12" total). CMC is my first choice for Jack Plates.
Here is where the tricky part comes into play. How much money do you want to spend, and what do you want to do with the boat? The reason I ask is that once you get a jack plate, other items will be necessary. You will need a nose cone/low water pick up. You will also need a water pressure gauge. IMHO, you will also need a heavy duty bearing carrier in the gearcase. The ONLY place to get a nose cone is Bob's Machine Shop in Florida. They are the BEST. They can also install a heavy duty bearing carrier. I would think you could get both of these items installed and shipped to and from for less than $700. You might spend another $50 on a water pressure gauge. If you do this combined with a set back plate, you will see at least 5 mph.
You need to maintain 12 PSI of water or you will fry your motor. The heavy duty bearing carrier is to keep your gearcase together when running the prop closer to the surface (which puts more strain on the case).

snappertapper
01-07-2003, 07:05 AM
i would say you need atleast a 6-8" setback

Charger 18
01-07-2003, 12:49 PM
Ok, thanks for the tips, the setback should be no problem to get and use, but my motor has never been rebuilt, it still runs good but I want to keep it around another couple of years and I think putting a hydraulic lift which will require a low water pickup is too much for the old thing to handle, remember we are talking about a motor that is almost 23 years old.
CrazyHippy,
To answer your question, I spin the prop at 5800, the rev limiter is 6000 on the motor.

HavasuDreamin'
01-07-2003, 01:24 PM
Charger 18:
Ok, thanks for the tips, the setback should be no problem to get and use, but my motor has never been rebuilt, it still runs good but I want to keep it around another couple of years and I think putting a hydraulic lift which will require a low water pickup is too much for the old thing to handle, remember we are talking about a motor that is almost 23 years old.
CrazyHippy,
To answer your question, I spin the prop at 5800, the rev limiter is 6000 on the motor. Remember, chopper prop = bow lift. That is what you need so that you can carry the nose with less trim. Cleaver = transom lift. You don't need that. Good Luck