I just got my 1648 Alweld and 40 Tohatsu w/ restrictor pulled. I am running a 13 pitch powertech prop right now. I love the set up, havent gps'd it yet but I would say upper 30's with 2 people 3 batteries and 6 gallons of fuel. i am interested in seeing the difference a 14 pitch would make, but on that size boat it may be too much. Any opinions?

14p Yamaha runs great on mine. But I have a weldbuilt. Little slower hole shot but fastertop end and can hold a load. It's the black painted stainless prop

I am leaning Tohatsu, going to be in Lake Chuck next week so will run by Lake Area Marine. Thanks guys, I will let you all know when I get the green light and can sell that ProDrive


One more thing: does anyone run a jack plate with their setup? Its mainly for getting into shallower areas thanks

I run a jack plate on mine. 10" set back. I don't run much shallow water but if you did I would go with lower pitch prop for hole shot.

I run a 6" on mine

Well I'm personally running an 04 Merc. 3 cylinder 40. If I had to buy new it would be Tohatsu. T.L.D.I. it's still a 2 stroke and will have more hole shot than a 4 stroke. It will also be lighter wich makes less drag and = more speed. Something to consider on you're prop selection. Lets assume you're running a 11-1/2" x 13pitch and you're turning 5500 rpm. Every number you go up in pitch you will lose 200 rpm. So 11-1/2 x 14p. = 5300 rpm. You will also lose hole shot with a higher pitch prop. Now every 1/4" you go down in diameter you will gain 200 rpm. So lets assume you swap the 11-1/2 x 13p. for a 10-1/2 x 14p. You will gain 800 rpm. because you went down 1" Im diameter. You will subtract 200 rpm. because you went up in pitch. So now you should be running 5900 rpm. The bigger the diameter the more power you will have low end and mid range. You will also be able to push a load better. The lower the pitch you have will increase you're hole shot but kill you're top end. Putting a cup in you're prop adds 1/2" to 1" of pitch. This will also help to stop cavitation in turns and in shallow water running. You hear stories about guys with the same boats and different motors getting way different speeds. The truth is a stock 40hp. motor pushes 40hp. @ target rpm. Prop selection is what makes the difference. What you have to decide is what best suits you're needs. If you're not running shallow water or the marsh, a smaller diameter higher pitch prop is you're best bet. If you're fishing the marsh or shallow water a larger diameter lower pitch prop is what you need. Assuming we're not including chopper or cleaver racing props, Yamaha makes the fastest prop on the market. The black stainless G series is the one you need. However powertech or stock mercury props are better in the marsh. Yamaha props are made of thinner steel than the others so they are faster. The thinner steel is why the other two will do better in the marsh. They are much thicker and will take more abuse.
I know it's alot of info but I hope this helps.

Good info, thanks for sharing.

Good Info. I like the 10-1/4" 14pitch. I don't run a whole lot of shallow stuff.

The computer is different on a tldi 40 than a tldi 50. The restrictor helps a little when removed but its not a 50. If you want a 50 then buy one because an ECU is over a grand.

This is what you need to make it a tldi 50.
http://www.internetoutboards.com/PartDetail.asp?id=1049

Good stuff, thanks.

Winner, Winner!!! Which is exactly why they pull the restrictor plate before you leave. Now you have nothing to compare speeds to. Try buying one stock, running it, GPS you're speeds, than take it in and let them pull the restrictor. They might do it, but I doubt it. Take a fools advice from someone who has been down that road. Buy it stock. Tune you're boat. Meaning setup, weight distribution, jack plate, prop, etc. GPS you're speed as you make adjustments. Once you find you're optimum setting, than have at. Hop it up all you want. At least now you can see the HONEST results of what you've done right there on you're GPS. For speed to increase 15% power has to increase almost 50%. I haven't personally looked at the parts diagram between the 40 and 50. I do remember on the 40-D and 50-D tohatsu put out in the mid 90's it was about $1300 in parts to make it a 50. Same block, different carbs, intake, and exhaust. I can believe the electronics are different on today's motor, I would also take a look at the exhaust as well.

The price difference in a 40d and 50d was about $400 if I remember correctly. Shoot it was $250 between a 25 and a 30. And all you had to do is take a throttle stop or on the later change the gasket behind the carb and it was a 30. Oh and bump timing 5 degrees. When I worked at DHP for the Pooles we made all the 25 hp motors 30 hp before they left the shop.

The G prop is an awesome prop for a flat bottom. The rake of that prop has a lot of stern lift which works great if you have a boat that wants to porpoise.

I personally had a tldi 40 that I bought used. It did have the restrictor in the intake. Made a run one afternoon and gps'd it. While on the water, I removed the restrictor and gps'd it again. Picked up 2-3 mph and it accelerated noticeably stronger. This was comparing apples to apples (same day, body of water, load, etc.). I'm not saying it was as strong as a 50, but it was definitely stronger than it was when it had the restrictor in.

The old 40D and 50D shared the same BLOCK, not the same sleeves, porting was vastly different. As a general rule, on a loaded boat, each additional 5hp will gain 1 mph.
D

Good info, I wasn't aware of that. So is the 50% h.p. for 15% speed ratio total b.s. as well? I want at all trying to give bad info. Just trying to help a guy out. I know exactly how it feels for someone to take advantage of you.

I run a 16x56 with the 40 tldi. 44 mph (gps) with a 16p black yamaha prop.

we got a CUSTOM FLAT 1544 . a little heavier gauge than avg..40 tdli runs 38 with 1 person or 3 loaded. increased 1 or 2 mpg when removed restrictor plate. when we got boat it ran 33. got a jack plate and raised it up just right to get xtra mph. Have not messed around with different props yet. runnin a 13p