Will I notice a difference dropping 1 degree of pitch on my prop?

kowached · 18 July 2006, 03:59

Hello all, I have a 4M Avon Searider with a "getting tired" Nissan 40 Hp. She labors getting up on plane with 2 people, and its a lost cause with 4 people. I currently have a 11 pitch prop and was going to replace it with a 10 pitch prop. Do you think dropping to a 10 pitch prop will make a noticable difference, or should I be looking at 9 pitch props?

The boat is equipped with remote steering/throttle, a full size deep cycle battery, and a 10 gallon fuel tank. As expected, there is an anchor stored under the seats, a spare prop, bellows, and some lines, add 600 lbs of people and she's pretty heavy.

codprawn · 18 July 2006, 04:23

Try a service on the engine - new plugs etc and maybe a better grade of petrol. Also make sure the hull is clean - no growth on it if kept in the water.

A new prop could well help - look at 4 blade ones as well.

kowached · 18 July 2006, 04:44

The boat is kept out of the water in a cradle, never any growth. I only use Nissan mix oil with a good brand of Regular (87 Octane) fuel. I was using Premium (93 Octane), but was told that due to its higher resistance to combustion I should stick with a good brand of Regular grade, thoughts?

New plugs and synthetic lube in the lower unit every Spring, and the engine probably only sees 10-15 hours per season. Inspected all of the Reed Valves, and replaced all intake gaskets, as well as rebuilt the carb with new OE jets.

gaviotapete · 18 July 2006, 04:56

hiya kowa-bunga
not sure if this helps but is it possible that your prop is too small?
my merc 40 is 18 years old and on my searider it flies and i'm running a 13 pitch 10" diameter prop. and i think the other searider4 guys on here (Nos4r2, boatster,ollyit, biggles etc..) are using 13 or even 14pitch props.

kowached · 18 July 2006, 14:29

Pete, I do have a 3 blade 10.2 dia X 13.9 pitch prop (spare under the seat) that I could try again (haven't had it on in many moons).

Once the Avon gets up on plane, she has no troubles at all and is a hoot to ride. She labors getting up on plane, so I was willing to sacrifice some top end in exchange for quick planing with 4 people. I'm thinking maybe I should get a 10 pitch prop, which is one pitch down from the stock 11?

gaviotapete · 18 July 2006, 15:30

hey Kowa,
have you considered the nuatilus smart tabs? there's some good threads/photos on here by boatster and ollyit and they are about $100 delivered. they help your hole shot big time. also you could take Nos4r2's tip about
inhibiting the speed of the flooding hull. i might be way off here but it seems like you are going fine once on the plane and just need help getting it up (searider cialis??) i think my standard prop is 13 pitch BTW not 11

codprawn · 18 July 2006, 15:46

Quote:

Originally Posted by kowached

Pete, I do have a 3 blade 10.2 dia X 13.9 pitch prop (spare under the seat) that I could try again (haven't had it on in many moons).

Once the Avon gets up on plane, she has no troubles at all and is a hoot to ride. She labors getting up on plane, so I was willing to sacrifice some top end in exchange for quick planing with 4 people. I'm thinking maybe I should get a 10 pitch prop, which is one pitch down from the stock 11?

On my SIB I have found moving people forward helps a lot to get it onto the plane - then they can move aft when up to speed.

kowached · 18 July 2006, 16:07

Thanks for the tips, I keep forgetting that the hull floods (haven't driven it since last season), I think that inhibiting the flooding of the hull is probably what I need to do next. I have heard great things about trim tabs as well.

All, thanks for directing me to look at other causes besides the engine/prop.