Propeller for Mac 26X

[Rick-D]

I have a 1997 26X with a 1996 50 hp Tohatsu. Long story short, been way under powered and took it into marina for repair. Needs to rebuild carbs, one is not working, but he also said I have a 3 blade prop that is 11.4 X 12 pitch. He said he believes it should be a 3 blade 11.1 X 9 pitch, which is the recommended prop for this motor. Just wanted to know what the best prop is for this motor and boat to get the maximum performance.

Thanks in advance for your advice,

Rick

[Keel_Hauled]

I have the same prop as you on my Suzuki DF50. I think their recommendation is probably right as I have researched and found mine would probably run better with a 11.8 x 9pitch 4 blade or a 11.8 x 10 3 blade....

[Don T]

Hello,
Somewhere in the archives is a ton of info on this. IIRC the prop you have is the custom one that BWY sold as the perfect match for the mac. The Nissan 2 stroke is only supposed to rev up to 5000 ~ 5500 RPM (as opposed to 6500 for 4 strokes). When I get home tonight I will check my Tohatsu 50.

Don T

[Tomfoolery]

He said he believes it should be a 3 blade 11.1 X 9 pitch, which is the recommended prop for this motor.

No prop expert, but prop selection depends on both the motor, and the boat. A work barge or pontoon boat will require a different prop than a lightweight planing hull go-fast boat, all with the same engine. You engine should be running in it's power band, wherever that may be with that engine and boat combo.

The general rule seems to be about 300 rpm for every inch of pitch change. Once you get it running correctly, take it for a ride and see what the tach says (ask the mechanic to check the boat's tach. against his shop tach. at high speed). Then make a decision about prop changes once you know where you're starting from.

Remember that it's not really practical to compare your engine against another brand, as the engine power bands can be at different speeds, and the reduction ratio may not be the same. Probably some other variables, too.

[Tomfoolery]

Well, found the specs on your motor, and it's 5000-5700 rpm with a 1.85:1 reduction gear for prop speeds of 2700-3080 rpm.

My Honda BF50 is 5500-6000 rpm with a 2.09:1 reduction gear for prop speeds of 2630-2870 rpm. Fair bit of overlap there. My prop is an 11-3/4" x 10" pitch three-blade, but I'm getting an Amita 11.8" x 9" pitch 4-blade for my birthday in a few days. I pull my kids on a wakeboard, and want to try a few things to make that better, though they think it's pretty good now.

Your engine runs a little faster at the prop, but 11.1 x 9 three-blade sounds a bit light to me. On the other hand, the 11.4 x 12 sounds like it's biting too much. But then, you'd have to try it with the engine running correctly to see.

Obviously, someone with the same engine and boat should advise you.

[Seapup]

You can always take her for a spin once she is tuned up, see what RPMS you are turning. If its the prop BWY suggested for that motor and it is in the 5-5700 that tkanzler looked up you are good. If the motor is becoming a bit tired and rpms are still low move down to what your mechanic suggests.

My Honda BF50 is 5500-6000 rpm with a 2.09:1 reduction gear for prop speeds of 2630-2870 rpm. Fair bit of overlap there. My prop is an 11-3/4" x 10" pitch three-blade, but I'm getting an Amita 11.8" x 9" pitch 4-blade for my birthday in a few days. I pull my kids on a wakeboard, and want to try a few things to make that better, though they think it's pretty good now.

If you have not ordered one yet you can send me a PM, I have an Amita 11.8" x 9" 4-blade for the honda left over.

[Rick-D]

Thanks for all the input into this matter. I know the engine never ran right because I could not get it over 3500 rpms without bogging down. When I first bought the boat I took it to an authorized mechanic and he tuned it up but I had the feeling it wasn't right. The person I have it with now is pretty pricy but I know he will get it right. I will try it with this prop if that is what BWY recommends, I have dealt with them and they seem to be the most up on this boat. One of the problems I noticed with this size prop it seems it did clip the rudder on the starboard side, indicating it may be a little too large but that has not really happened with me, had to be from the previous owner.

Thanks again for all the advice.

Rick

[robbarnes1965]

You can always take her for a spin once she is tuned up, see what RPMS you are turning. If its the prop BWY suggested for that motor and it is in the 5-5700 that tkanzler looked up you are good. If the motor is becoming a bit tired and rpms are still low move down to what your mechanic suggests.

My Honda BF50 is 5500-6000 rpm with a 2.09:1 reduction gear for prop speeds of 2630-2870 rpm. Fair bit of overlap there. My prop is an 11-3/4" x 10" pitch three-blade, but I'm getting an Amita 11.8" x 9" pitch 4-blade for my birthday in a few days. I pull my kids on a wakeboard, and want to try a few things to make that better, though they think it's pretty good now.

If you have not ordered one yet you can send me a PM, I have an Amita 11.8" x 9" 4-blade for the honda left over.

I have an 11.8x9 4 blade on my honda 50 and have not been blown away. But then again I always seem to have the boat loaded with crap. If I remember correctly, my motor rpms go off the chart at about 5500 and the boat slows down.

[DaveB]

I have the altima 4 blade 11.8 x10 on my Honda 50 1997. I have tried 3-4 diffrent props. and like the 4 blade as I do 6 knots, full power can only do 4650 rpms but thats ok with me. Top end is 14.4 mph in a very loaded boat after 4 days. Granted, reduced weight on fuel,water and provisions gave me that 14.4 mph, in the biginning of trip I would say around 13.5 mph top speed or less.
I like the low speed and if any wanted more than the 9 pitch would be better. Bear in mind I have at least 900 lbs in equipment on board than stock.(not including people)
crew weight 425 lbs., 3 anchors with 25 ft. chain each, 3 batteries, 65 edgestar refig, 13 gal. water tank, 5 gal. portipottie,3 diffrent grills, 300 lbs of firewood ...etc.
The Higher pitch prop. is great for 6 knots at lower rpms.
For the Honda BF 50 I would agree the 4 blade 11.8 X 9 pitch is the best for most boaters.
Problem is the BF50 is not a high thrust engine like the Big Foot Merc.,Johnson 60, Yamaha and new 60 hp Honda.
Larger Props. of these outboards with a 13 + diamiter prop with 3 blade is much beter.
Dave


I have an 11.8x9 4 blade on my honda 50 and have not been blown away. But then again I always seem to have the boat loaded with crap. If I remember correctly, my motor rpms go off the chart at about 5500 and the boat slows down.[/quote]

[Tomfoolery]

If you have not ordered one yet you can send me a PM, I have an Amita 11.8" x 9" 4-blade for the honda left over.

Thanks for the offer, but I have the same prop, new in the box, sitting nearby waiting for Monday. My FIL, who likes to buy boating stuff for me whenever there's a reason to (Christmas, fathers' day, birthdays), had it shipped here a month ago after I said something out loud. Since he's pretty much my only regular crew, he likes to do stuff like that - unless it costs too much. And since he sold his big trawler, my little is his summer boating recreation now. Works for both of us, though.

Thanks, though.

[133bhp]

Where is the stamp on a prop located typically? Need to confirm mine is correct also for my m50d2.

[Keel_Hauled]

The stamp is usually stamped on the inside rear of the prop. You have to remove the prop and look at the back, like this:




~K

[133bhp]

thanks, exlains why I could'nt observe from the dock!

[Catigale]

Side of the prop for the Mercury Bigfoot series at least. Visible without removal.