Pitch question

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chwebmaker

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I am new to this site. I have a 1548 Tracker Grizzly. I recently bought a Tohatsu 20hp to use on this boat. I also just completed adding an aluminum floor and extending the front aluminum deck another 40", added compartments and added aluminum compartments between the rear bench seat and transom. My question is related to pitch and the prop that came with the motor. In my estimation, the boat weighs 560lbs + 320 lbs of gear and motor and another 2 people 320lbs for a total of 1200lbs. The stock prop on the Tohatsu 20hp is a 9.2" Dia. X 9.8" Pitch 3-Blade Aluminum. Should I get another prop with a lower pitch such as an 8" before taking it out on the water for the break in period. Also, since I am pushing alot of weight, would it be worth getting a stainless steel prop. I appreciate any advice you can give me.
 
Its a brand new setup so its all guesswork at this point. Get some breakin time on your engine before making any test runs or decisions that cost money. When the engine has enough time for a full throttle burst, have your tach hooked up and ready. Your first full-throttle tach reading will tell you if you're in the ballpark or not.
 
I appreciate the info and I assume I should buy a tachometer. They look pretty easy to set up...one wire to ground and one wire around spark plug wire. Is that how this works? I apologize for the rookie question.
 
definitely get a tach. I would take it out the way it is and see where you at before buying parts. tha tachs are usually easy to setup. I have the merc. 20 on my 1448 SC grizzly. I ended up dropping from a 10p to a 9p 4blade. made a huge difference. I started doing all kinds of stuff then the 4 blade helped tremendously. just do your homework and take your time.
 
A tach is required (not an option-it is required) to tune for any prop, on any boat, on any motor. Doing it any other way is just guessing and assuming. Pretty sure you're gonna have to drop to at least a 9", maybe an 8".

Break it in with what you have. Then play with it later on AFTER the tach is installed.
 
[url=https://www.tinboats.net/forum/viewtopic.php?p=351354#p351354 said:
turbotodd » 05 May 2014, 21:30[/url]"]A tach is required (not an option-it is required) to tune for any prop, on any boat, on any motor. Doing it any other way is just guessing and assuming. Pretty sure you're gonna have to drop to at least a 9", maybe an 8".

Break it in with what you have. Then play with it later on AFTER the tach is installed.
Click to expand...

Tach is ordered and on the way. Thanks for the advice guys.
 
[url=https://www.tinboats.net/forum/viewtopic.php?p=351209#p351209 said:
chwebmaker » 04 May 2014, 21:34[/url]"]I am new to this site. I have a 1548 Tracker Grizzly. I recently bought a Tohatsu 20hp to use on this boat. I also just completed adding an aluminum floor and extending the front aluminum deck another 40", added compartments and added aluminum compartments between the rear bench seat and transom. My question is related to pitch and the prop that came with the motor. In my estimation, the boat weighs 560lbs + 320 lbs of gear and motor and another 2 people 320lbs for a total of 1200lbs. The stock prop on the Tohatsu 20hp is a 9.2" Dia. X 9.8" Pitch 3-Blade Aluminum. Should I get another prop with a lower pitch such as an 8" before taking it out on the water for the break in period. Also, since I am pushing alot of weight, would it be worth getting a stainless steel prop. I appreciate any advice you can give me.
Click to expand...

Here's an update to my original post. With the pin on the motor set in the second hole (factory setting) I get 5940 RPM's and 22.5 mph. Moving the pin to the third hole goes to 6000 RPM's and 23.4 mph. Moving the pin to the fourth hole goes to 6180 RPM and 24.5 mph but with two people it takes longer for the front of the boat to go down and get on plane. Should I stick with the original prop 9.2" Dia. X 9.8" Pitch 3-Blade Aluminum, is 5940 - 6180 RPM's too high? Will I pick up any speed with a stainless prop? Thanks in advance for your feedback.
 

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