prop performance

chas · Posted: Sun Jul 11, 2010 5:13 pm Post subject: prop performance

I have a 40 hp honda on a 16ft angler and normally have one passanger & fishing tackle on board. My concern is that at wot, the best that I can get is about 2100 rpms. The gps has the boat moving at around 27 mph.. The prop on the motor is an 11.1 X 13, Should I be looking at a different prop or possibly could the tach. be defective?
Chuck

Captains Cat · Posted: Sun Jul 11, 2010 5:32 pm Post subject:

Sounds like a defective tach. 27MPH should be just about WOT with a 40. Has it always been that way or is this a new problem? Some tachs have a switch on the back for 2-4-6 cyls, if yours does, it may be in the wrong position. Your tach should be reading btwn 5K and 6K RPM.

In reading your posts, I see that you got the boat in April. It might be worth a call to the previous owner and ask the question.

Charlie

Wandering Sagebrush · Posted: Sun Jul 11, 2010 6:21 pm Post subject:

I agree with Charlie. If you're getting that kind of speed, the tach is probably off.

Check the back of it. There is a switch that (if I remember correctly) allows you to select the number of cylinders for the engine you're using. On my first BF 90 (Arima 17), that switch was either in the wrong position, got a bit of corrosion/resistance, or was just being a pill. When I moved things around a bit, and then back to 4 cylinders, the tach started working fine.

Honda tachs are a bit less than stellar in my book...

Steve

chas · Posted: Sun Jul 11, 2010 7:39 pm Post subject:

Thanks , I purchased the boat new last April and have had a great time with it. Will check the connections or switch on the tach.

Zricky · Posted: Mon Jul 12, 2010 12:51 am Post subject:

I dont know if this helps but I have a 16 with a Honda 40, at WOT my RPM is between 5.5 and 6 about 23mpH. My propeller says C3X11.1X13.

chas · Posted: Sat Jul 17, 2010 10:06 pm Post subject:

I just returned from the water, the selector switch on the tach was set at "4" I set it for "3' and the tac now reads 3100 rpms (orginally 2100 when set at "4"). will continue to play with the settings on the tach.