Wrong pitch?

[Eshaw150]

I just took my boat out for its first time with a new used motor the motor is a 1999 suzy 140 2 stroke the prop is i belive 13-17
it runs 4k rpm when its not even planeds at 20kts

the old motor had a dead cyc was a johnson 150 vro and it had a 13.5-19 pitch prop at it pused it twice that at less rmp

should i get a diffrent prop the same as the old one

 

[Bondo]

Re: Wrong pitch?

Ayuh,... Sounds like Suzy might be Sick.....

You'd need a Smaller Prop to raise the rpms,... Not larger....

 

[Eshaw150]

Re: Wrong pitch?

no i want to lower them its taching to high

 

[steelespike]

Re: Wrong pitch?

What boat?style,weight, bottom?What is the actual wot(wide open throttle) rpm and speed. Motors rated rpm?You can run 200 or 300 over rated rpm
long enough to get your actual wot rpm.Is the tach at the proper setting?
Is the new motor more or less cylinders?Tach needs to be set to match.

 

[Eshaw150]

Re: Wrong pitch?

What boat?style,weight, bottom?What is the actual wot(wide open throttle) rpm and speed. Motors rated rpm?You can run 200 or 300 over rated rpm
long enough to get your actual wot rpm.Is the tach at the proper setting?
Is the new motor more or less cylinders?Tach needs to be set to match.

motor is 2 less but 10 hp lower wide open is about 5800 rated im not sure at 4000 is abbout 20 knots not planed by gps tach is a new suzy tach set correct

pitch is less on prop with newer motor than old motor is 2 inch more pushed it better running on a dead cyclinder

motor is taching to high for speed trying to get on a plane prop is also stainless stell
boat roughly 3-4k lbs loded fully fuled and gear with 4 passangers
20 ft traveler v bottom deep v cc

 

[junior1113]

Re: Wrong pitch?

3-4 k for a 140 suzi is quite a bit for a four banger with a 17 pitch u need like a 13 or less if the motor could even do it your 150 was a lot stronger than the official 10 hp difference 6 cyl is where u need to be they have the torque

 

[steelespike]

Re: Wrong pitch?

I couldn't find a 140 anywherte in the line up.only 130 and 150??
Check the prop size for sure.You need to know the wot max rpm and speed to figure an accurate prop change.You can't guess weight.add up typical load including the motor.
Don't forget gas and battery.4,000 is a bunch for a 140.3,000 obviously more manageable.

 

[Eshaw150]

Re: Wrong pitch?

well i never had it toped out i took it up to 4800 and it came out the plane now i took it to where i bought the motor and they changed it to a 16 pich prop the

one question i have is the higher the pitch does it move more or less water

 

[junior1113]

Re: Wrong pitch?

higher pitch more water at equal rpm but also lessens wot rpm i had a 21 at 5000r's 43mph 19 5400r's 43 mph 17 5800r's 44mph hope this helps

 

[Eshaw150]

Re: Wrong pitch?

ok then i think we are going the wrong way i want it to plane out a little earlery the 4100 rpm and it had and 18 on it the shop exchanged it with a 16 pitch my dad is kinda realy into boats and this is like a deep v offshore fishing boat but i have never heard of spaller than a 19 on anything other than a bass boat

the old motor had a 19 pitch prop i though worked pretty good but i dont want to boog it down and under rev it i guess its going to be hit and miss with this one

the max rpm buy the way is 5500-6000 wot
2.08 to 1 gearing im trying to get it around 40-50 miles an hour wide open

because we plan this year that we are going to go to the artificial reefs out side of tybee

 

[Bondo]

Re: Wrong pitch?

Ayuh,...

At this point,... You absolutely Have to go out,+ Run it to WOT,+ See what the rpms are....
Then,+ Only Then can you decide whether to Increase or Decrease the pitch to make the motor run At the recommended RPMs at WOT....

the old motor had a 19 pitch prop i though worked pretty good but i dont want to boog it down and under rev it i guess its going to be hit and miss with this one

The old motor,+ the new motor are Apples,+ Oranges....

im trying to get it around 40-50 miles an hour wide open

I think you're Dreaming if you think 150hp is going to push a 4000lb. deep-v to 50mph...