Logo
FULL SITE MENU

Pulling back at full throttal

S

seaangler

New member
Hi..I have just required a dor

Hi..I have just required a dory 14 with a 30H/P yamaha T/S autolube..The chap who sold me the boat said it has a nine and a half inch prop on it...And at full power you have to just pull the throttal back a bit...to stop it from juggering at full speed...Do you think that i need a slightly bigger prop or even if its the right prop for the engin...Any help would be very greatfull from a new B....Cheers for now Chris
 
"Christopher, the pitch sounds

"Christopher, the pitch sounds a little low for a 30 horse on a 14 footer - depending on the weight of the boat.

I have a 14 foot alumimum, when loaded with myself, the wife and fishing junk for the day weighs in at about 850 pounds (total weight). With that set-up I push it with a 15 horse turning a 4 blade, 11 pitch in the spring and fall and move down to a 9 pitch (3 blade) in summer.

The only sure way to determine what size pitch is with the aid of a tachometer. But at a rough guess you could easily move up to an 11 or 13 pitch without issue..."
 
Cheers for the info Graham..Bu

Cheers for the info Graham..But as you say going down to a nine inch three blade in the summer.. Am i still going to get that jugger...Or if i move up to a 11 inch what is the avantage and will it stop the judder at full speed...Unless i do as you say and get it tested with tachometer..
 
"We can kinda "guess"

"We can kinda "guess" at what will work, but that can be an expensive process if you pick the wrong prop.

Perhaps a shop can loan you a tach.

Alternately, there is a product called "tiny tach" (and a few "knock offs" that work the same way) - sells for about 30 bucks (on my side of the pond) and it's hooked up by simply coiling it's lead wire around the #1 spark plug lead - it then gives you the rpms on a little LCD gauge - the perfect tool for small outboards.

You want to shoot for the mid 5000's at full throttle, only a tach can really tell you where you are.

From there for every 1" increase in pitch, your rpms will drop by about 200 (and vice versa)."
 
Back
Top