honda 40 hp 4 strk prop size?

[dmurray]

I have a 97 or 98 honda 4 stroke 40hp. I am pushing a alumacraft (river boat) appx 600lbs. I am wondering if there is a good site to visit or if someone can tell me what size prop I should get for top end? Book reccomends around 5500rpm top end.<br />thanks,<br />don

 

[hondon]

Re: honda 40 hp 4 strk prop size?

you are leaving us with alot of unanswered questions.What kinds of loads will this boat typically be working with ?Will you be running up full and coming back lighter or visa versa?Flat bottom or mod vee or vee hull?Your best bet is to ask at the dock .Ask of someone that has a similar rig with similar circumstances.That will get you real close if not right on.

 

[dmurray]

Re: honda 40 hp 4 strk prop size?

Thanks for the reply hondon,<br />I will only be going out with my son and myself. Max load will be an additional 450 lbs. I only have a 6 gal tank and every time I return I still have 3 gallons. Occasionally we catch some fish and come back a few lbs heavier <br />Don <br />DIMENSIONS <br />Length 16'0" / 4.88m <br />Width–beam/bottom 74"/50" / 1.88m/1.27m <br />Side Height 21" / .53m <br />Transom–width/height 69"/20" / 1.75m/.50m <br /> <br />CAPACITIES <br />Horsepower–maximum 60 HP / 45kw <br />Capacity–persons/lbs. 5/1010# / 4/458kg <br />Weight–lbs. 510# / 231kg <br />Fuel Tank - Portable 9 gal. / 34 l <br /> <br />ALL-WELDED HULL <br />Thickness bottom/sides .102" / 2.5mm <br />• All-welded modified-V with 11 extruded ribs

 

[hondon]

Re: honda 40 hp 4 strk prop size?

I'dd be thinking a 12 or 13 pitch would be close. I always like to verify those choices with a shop tach.Handheld remote chainsaw tachs work nicely with these engines but you have to move them around the wires a little and have the ear to know it is giveing the info you want.You really want that 5500 to be your bottom spec.Shoot for the 6000.

 

[Silvertip]

Re: honda 40 hp 4 strk prop size?

Without knowing WOT RPM on your current setup, picking another prop is a guessing game and it may be that a prop change is not even necessary. For example, if WOT RPM is 6000 RPM for your engine and with the current setup its only turning 5000, you are lugging the engine and could use a prop with less pitch to bring the RPM up. Conversely, if your current RPM is over 6000 RPM you are over-reving and would want to increase pitch to bring RPM back into the proper range. If your current prop provides 5800 - 6000 RPM with the load you normally carrry, no prop change is necessary.