Running wide open..

[Bass Tard]

So I just broke the boat out on the weekend to make sure it still floats and everything works before opening day, everything worked just as last year, minus a bad ground on the trailer but that's an easy fix.

 

Now, in our old boats we had a 20hp Johnson and a 9.9 Evinrude and since they were really small and really slow, I would pretty much always run them wide open and really never thought twice about it because they never seemed to have a problem with it, even for extended periods (half hour trip or so). On my new boat it has a tachometer and it has a red zone at around 6,000rpm, but that's about 3/4 of my throttle. Just to be safe I usually will run it around 5500, but I'm wondering how bad it is to just open it and run it all out?

 

Also, is there a way of finding out if my batteries that have been in storage all winter are still as good as last year? I didn't charge them or anything, I hope they're okay.

 

Horay for bassin'!

[Garry2Rs]

In the owners manual or on-line you will find the max RPM's for your motor.

If you are reaching that engine speed at less than full throttle you might want to try a longer prop...21 inches in stead of 19 etc. Prop length is a compromise taking into account the boat and the load it carries etc. Ideally you want a prop that gives you a decent hole shot, and will let you get within a couple of hundred RPM of the red line flat out.

 

Any battery shop can load test your batteries for you.

[DRIFTER_016]

First of all you need to know what the top RPM your motor is supposed to turn at full throttle.

Hull type, length and weight would help too.

 

If you are hitting te redline at 3/4 throttle you need to change your prop.

You should be 200-400 RPM below redline at full throttle.

For every inch you go up in pitch you should drop 200 RPM.

[Terry]

they gave you good advise it's all in the prop

[Bass Tard]

Alright, thanks guys. It looks like I need to do some more research and hopefully I can get everything straight.

 

I don't really have a lot of information on the boat, no owners manuals or anything. Its a 17.5' Bass Tracker with a riveted Jon boat hull. The motor is a matching 89 Evinrude Tracker 50hp.

 

Is a stainless prop my best bet? (once I figure out what size/pitch)

[DRIFTER_016]

From what I have been able to find out the manufacturers max RPMs are 5500 at WOT (wide open throttle)

You want your engine to run between 5000 and 5500 at full speed.

With the proper prop on there you should pick up some top end speed and save your engine from over revving.

 

Here's some good prop info for you.

 

Propellors 101

[charlesn]

Make sure your tach didn't go wonky. 6000 rpms for a 50 HP sounds high. Might be worth taking to a mechanic to verify the readings you are getting on the tach.

 

If they are correct, then you need a bigger prop like the guys above said. Before you spend money on props though, make sure the gauge is reading accurately.