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1978 predictor repower and prop size

J

james

New member
i have a 78 predictor with a 77 140 johnson and i just got a 86 150 mercury to go on it what prop i curently run a 19 and a 21 mostly the 19
 
I'd stick more with a 21-23 pitch for speed or a 19 pitch for hauling. I dont share the love for the lazer 2's.
 
23P I would say if you want a good all around prop without running any setback.

The even number LazerII props have a small hub diameter.

I have run all kinds of lazerII props. They have worked well for the money on small boats. :thumb:
 
speed

what kind of speed should i get im running 200 carbs carbonfiber reeds 10 inch tuner no exahust can and drilled
 
low to mid 70's I would say.
for props, I've had great experience running trophy's and i'd suggest somewhere in the 25 or 26 pitch range depending on your gear ratio with a 150.
 
You arent going to low to mid 70's in a predictor with a stock '86 150. Nor would you want to without a steering upgrade. Low 60's. 65 GPS with the current on a cold day Too much of a prop and you just won't get into your power range. You can bolt a 26 pitch prop to it and it will turn but if you cant get over 4800 RPM its not doing you any good.
 
wired said:
You arent going to low to mid 70's in a predictor with a stock '86 150. Nor would you want to without a steering upgrade. Low 60's. 65 GPS with the current on a cold day Too much of a prop and you just won't get into your power range. You can bolt a 26 pitch prop to it and it will turn but if you cant get over 4800 RPM its not doing you any good.
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I think I was hitting just shy of 60 (say 57-58) with my 150 before it ate a piston. Definitely want at least double cable steering.
 
jumbofordman said:
I think I was hitting just shy of 60 (say 57-58) with my 150 before it ate a piston. Definitely want at least double cable steering.
Click to expand...

Ive run 75 MPH with a single cable and that was with a 225 and a 260 where I had both of them trim full negative trim with the bow of the boat a few inches off the water. Ive got the same hull. ANY trim and it was an uncontrollable nightmare.

Solid motor mounts and hydraulic steering and I can go about as fast as I feel like going or at least as fast as the motor will make me go. If I was running a 150 I'd expect that would be mid 60's
 
There are a few predictor/150 merc combos on this board running over 70, one of them being on the same lake as me. Important setup items include a jackplate, scoops or low water pickup, water pressure gauge and at least dual cable steering or better.
 
I run a 21p laser to prop on my 86 enticer 16 foot with a 150 xr2 and run 62mph GPS at 5,800 rpm I also run a 25p laser 2 prop and got to 63 to 64 at 5,400 rpm with over trim! I blew that motor up(2nd motor I put on boat) and I'm sure the reason was the 25p was too much and was lugging the motor! The 21p was perfect with 3 people a half a tank of gas in boat I could pull a wakeboard out the water better than my buddies triton 19ft with a 175!!
 
Run your numbers on the prop calculator. Here's what I get:
5800 1.85 22 .0507 62 (for the 21)
5400 1.85 25 .088 63 or (24")
5400 1.85 25 .0738 64
I'm getting ready a 14x24" 2 blade Merc HP bronze for my 87 Johnson 140 on a
CVX 16 (weight 700 lbs) that I re-hubbed. Also have a 13 3/4x23 2 blade and 20 Raker and 21 Mich SS props.
 
I'm with the Great East Predictor! It can be done!

I currently have a 78 V-Mate 1 with a 5.5" manual CMC jp and a 150 xr2 with the idle stabilizers removed and full timing statically set, no other mods... Running a 26p Laser II it ran 72-73mph on GPS and with my ron hill 26p Chopper ran 73-74mph. Turning 6400-6500rpm. The v-mate is lighter and a foot shorter but it also doesn't have a true pad to ride on so there is more drag in the water.

I had a 79 predictor with a slightly modded 2.4 200 with a nose coned case running 83mph on GPS with a 27p B&B Trophy.

If it's an xr2 then the gear case should be 2:1.

I would definitely try a 24-26p laser II and a 26p chopper if you can find one.

If you are bolting it directly to the boat, mount it as high as you can but a jack plate will be a must to get the most out of it.

It's all about the setup......
 
I would say u might see low 60's with the xr2. I have a 86 enticer 16ft with a slightly moded 150 xr2 drilled and hollowed out mid, shaved heads to get compression up and carb work with a 8in manual jack plate and I have taken out all the wood in boat seats and replaced entire interior with aircraft honeycomb! A 4x8 sheet weight 10lbs!! So I've shaved 50 pounds out of my boat and with solid motor mounts prop shaft 1/2 inch above pad single cable steering with a 24p small ear chopper prop I cupped and worked my self I just can see 69 and that's all she's got!
 
If the setup is correct you will be over 70 MPH, provided the motor is running correctly. DS280 has a Predictor with a 140 Johnson and he can run in the mid sixties, and he has a new single cable steering setup, although I would recommend dual cable for safety.
 
Its not just safety. Its the practicality of it. Single cable systems are not capable of running at high speeds. The motors is not under control and it flops from side to side whether or not it lets go. Dual cable or hydraulics hold the motor firmly in place and prevent the side to side shifting that gets called "chine walk". You won't realize until you get a decent steering system how bad your old system was.
 
robert2278 said:
Does yours chine walk? my 86 predictor with a 140 did it really bad.
Click to expand...


It chine walked because you did not have motor control. It just flops around. Add hydraulic steering and solid mounts and you can drive it as fast as you want or at least as fast as the motor will push it. I cruise in the 70's and could do it hands off the wheel.
 
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