Changing the prop on Tohatsu 6 hp. "UPDATE"

Sea Eagle Mark

Seaman Apprentice
Joined
Feb 4, 2019
Messages
49
So the summer has come and gone, with just a few more good weeks left here in New England. We love our Sea Eagle 12.6sr, it has exceeded our expectations in every way, and we're glad we bought it. I had thought about changing the pitch of the prop on the Tohatsu back in June to give us more "hole shot" when loaded with the two of us. Turns out I think I'm going to leave things the way they are. After 12 day trips and 42+ hours, we consistently have clocked 9.3+knots (10.7mph) loaded, and 12.7knts solo, (14.60mph) way better than I expected with a 6hp. Mostly we're exploring quite marshes, rivers and small harbors and relaxing at anchor. We almost went with the 9.8, but, age, health and cost were concerns. I can just manage the 57lbs, not sure about the 85+lbs of a larger motor. Plus, we rarely use more than $2.00 worth of gas! Gotta love that. Thanks again for all your help and input.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Did you changed the factory delivered prop by going one less pitch or that didn't happened ? If so there's a big water performance difference when boating more loaded than when solo boating.

All 209 CC 4 strokes 6-8-9.8 HP motors weights exact same 37 kilos, can be converted between them by a simple carb swap if in a future need to convert that 6 HP to a 9.8 HP. There's a lighter 25 kilo 123 CC 6 HP, which one is yours ?

Happy Boating
 

Sea Eagle Mark

Seaman Apprentice
Joined
Feb 4, 2019
Messages
49
Hey SR, NO, I never changed the prop! I think I'm going to stay with what we have for now as we're happy with the performance so far. We have the lighter 25 kilo (57lbs) 6hp Tohatsu and it runs great. Never had an issue with it all summer. Runs like a champ, and yes, there is a big performance increase when I take the boat out by myself, then it flies like the wind! Thanks again for all your help and input it's much appreciated. This fourm is very helpful. 😀
 

Black Rat

Seaman Apprentice
Joined
Nov 22, 2018
Messages
41
I just bought the Tohatsu 6hp OB and wonder if you have a rough idea on how many miles you get per gallon of gas at half throttle. I'm planning a possible photography adventure in Lake Powell next year with my 14' SIB and the gas is expensive and far away between stops.
 

Sea Eagle Mark

Seaman Apprentice
Joined
Feb 4, 2019
Messages
49
Hey BR, our Tohatsu 6 hp has both the internal tank and the option for an external tank. (Which we DON'T have yet) I've come to realize that anything over 1/2 throttle and the gas consumption go's WAY up and you just get a slight increase in speed. With that said, at 1/3 throttle (about 3-4knts) I can go about 8-10 miles. At 1/2 speed 5-8 miles. I'd guess 3-4 at full throttle, but I've never tried that. May I suggest you bring a 1- 2 gallon plastic gas container for refills. Right now that works for us but it can be annoying. One trick is to reset your GPS to 0nm and depending on speed keep an eye on how far you go. If you're going to do long trips consistently I'd buy an external 3 gal tank. Hope that helps. Mark C.
 

Black Rat

Seaman Apprentice
Joined
Nov 22, 2018
Messages
41
My model came with the 3 gallon tank. I did buy a spare prop and like you stayed with the original. I ran across a Tohatsu fuel consumption chart and it showed the fuel consumption was about a third of what my 25HP burns which makes sense. I did find one owner say his sailboat made about 10.1 miles to the gallon which is what my 25Hp does but he had a big boat he was pushing.
 

Sea Eagle Mark

Seaman Apprentice
Joined
Feb 4, 2019
Messages
49
It's a gray area at best trying to "guesstimate" fuel consumption. Too many variables. Wind, current, total weight with gear. With that said do your planning on a chart and do a "time, speed, distance" calculation to see how long it will take at different speeds. Then plan for extra gas! 😀 Have fun and let us know how your adventure went.
 
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