Problems when I get a more powerful prop

[Rich L]

I'm getting a more powerful prop (lower pitch, 4 blades) designed to push a heavier boat. My stock Tohatsu 8 hp comes with a medium power prop designed for about 1000 lb boat. My H26 is probably closer to 4500-5000. I have lousy low speed performance. My reverse takes about 10 seconds to stop the boat as I'm entering a slip at less than a knot. That's an eternity! I do have a long shaft that extends well below the transom.With the new prop, I'm a little worried about over-reving the engine when I'm cruising on windless days. The cheapest tachometer I could find was 1.6 times the cost of the prop (which was $86). Any ideas for where I could find a reasonably priced tach?

 

[Wanderer138]

Why get a tachometer?

If I understand you correctly, you needed more thrust at low speed, which means you replaced the stock prop with one that has more blades and possibly more pitch and/or a larger diameter.That sounds like more load on the engine to me, which means that at full throttle with the new prop, the engine should turn at lower rpm than it did before. No danger of over-revving there.You maight also want to check your speed under power. Once the boat is up to maximum speed, you should be able to throttle back to about half power without any real loss in speed. Your engine will appreciate it (less wear and tear) and your range on a tank of fuel should almost double. Give it a try before you spend your hard-earned cash.PeterH23 "Raven"

 

[ed]

ole petes right.

if you stay with a dealer supplied design and pitch for more power you should be fine. may not go quite as fast but should help.Stoping in ten seconds is pretty good on lots of boats. you just got o learn to slow down earlier!remember outboards put exaust out thru and arround the prop/ when you back you get lots of air and less water to stop ;you.

 

[Rich L]

Thanks, guys

Somehow, I thought that the higher pitch, 4-blade prop would spin faster at higher speed than a low-pitch 3-blade. Guess I got it backwards.Thanks - I like good news...