Question about WOT for yamaha 150

[Delta Drifter]

At WOT on my 180 (yamaha f150), I hit 5100 rpm with 39 mpg today.
I think thats pretty good.
What is your performance data like?

(Approximate extra weight 350 lbs which includes my weight and two batteries plus a bow mounted trolling motor.

 

[gerrys]

At WOT on my 180 (yamaha f150), I hit 5100 rpm with 39 mpg today.
I think thats pretty good.
What is your performance data like?

Do you mean MPH?

5100 is a little short on top end rpm's.

What model, year boat?

The performance chart shows 5800 top end.
http://www.gradywhite.com/popup/specs.p ... &file=F150

 

[CJBROWN]

Yamaha recommends 5500-6000 for the F150. This means you're a little over-propped. Consider dropping a couple of inches in pitch. The warn about lugging an engine with too much prop, causes premature wear.

Do you know what size and type of prop it has?
For a 180 at that rpm they must have put a 19" pitch on it. Exchage it for a 17.

You'll probably pick up a mile or two per hour at top end.

 

[Delta Drifter]

5100 rpm hitting 39 mph.

I have a 2007 Sportsman with F150.

Comparing to the Data on the Grady website, it appears that
I am good at 5000 rpm. But, that is my WOT.

Is there anything I can do to improve my WOT rpm and speed?

 

[Delta Drifter]

CJ

Can you tell me what your rpm and speed at WOT with your boat.

I don't know exactly the pitch of the motors prop.
But, I will find out for sure.
Thank you for the tip.

 

[BobP]

Why is Grady over propping the F150s? Does Yamaha know?

 

[CJBROWN]

Bobp,
Don't the motors ship without a prop? Do the pre-rigs get a prop put on them or does the dealer guess?

Drifter,
I run a 15-1/4X15, turns 5700 at 38.5mph on the 208, medium load. I've tried a few others, ran a stainless in the same size for a while but it chattered at idle in gear, so I went back to the stock aluminum. Works just fine for me and they're cheap :wink:

I would have to look up the performance specs on the Grady site for the 180, not sure what they did. I suspect its the same as every other though, the 13-3/4X17, that's what they test on everything.

If you dealer or previous owner installed a 19 it's the wrong prop.

 

[Delta Drifter]

CJ,

The performance data for Grady shows 13 3/4 x 19 M.

That is great that you can run at 5700 rpm. I am definitely going to look into replacing the prop.

Why is it that when we run at 39 mph on the Grady and it feels soooo good but drive 75 mph on a car and it's boring?

Thanks again.

 

[BobP]

These Gradys are pre rigged motor and all at factory then placed in clear shrink wrap, from what can see. Dealer doesn't have much to do.

 

[CJBROWN]

CJ,

The performance data for Grady shows 13 3/4 x 19 M.

That is great that you can run at 5700 rpm. I am definitely going to look into replacing the prop.

Why is it that when we run at 39 mph on the Grady and it feels soooo good but drive 75 mph on a car and it's boring?

Thanks again.

There should be a stamped number on the hub, next to one of the blades. It will say 17M or 19M, that's the pitch. If you remove the prop there will be a cast-in number with the diameter and pitch on the back of the hub where it meets the output shaft.

Is a stainless prop? It could be that someone put a Saltwater Series prop on it, or something with more cup in a 19" pitch. The stock aluminum they test with don't have as much cup as many of the aftermarket props. It could also be one of the black painted stainless ones that Yamaha sells.

Water speed always feels more than land speed. Can you imagine what those race boats feel like that do over a hundred? Or an unlimited hydro at over two hundred?

 

[BobP]

If that's a new Grady discuss with dealer, may have a e free one time exhange for another prop.
Yamaha dealer policy for yamaha props, learned when I bought my props.

 

[Delta Drifter]

Speed is Addicting! Especially on a GW.

I will go check the prop this weekend and post my findings.
Also, once I have all the info, I will check with the dealer for a free prop.
Thank you BobP for your input.
Thanks again CJBrown.

 

[JUST-IN-TIME]

are u trimming it out?

 

[Delta Drifter]

There are so much boating knowledge on this forum. Its great. All this input is really helping me alot at this time.

I am trimming the boat to my best knowledge. I look for the rpm and the speed to go up or down as I tune the trim tab switches. Is this correct?

 

[JUST-IN-TIME]

just use the trim on motor
you will see it rise so will speed
but u really need flat conditions

if u trim too high rpm will go up and speed down

 

[Delta Drifter]

I am going to try what you suggested next time and pay closer attention to the change in the rpm and speed.

Thanks for the tip.

 

[ocnslr]

There are so much boating knowledge on this forum. Its great. All this input is really helping me alot at this time.

I am trimming the boat to my best knowledge. I look for the rpm and the speed to go up or down as I tune the trim tab switches. Is this correct?

At WOT in smooth water, your tabs should be all the way up. We are talking about triming the ENGINE up as you watch the RPM and speed increase, then you will hear the engine ventilating (i.e. RPM increases and speed either stays the same or decreases). When that happens just trim the engine down until it "bites" again. That is your best WOT speed and RPM.

You should prop the engine so that condition puts you at the upper end of the specified RPM range (i.e. about 6000 RPM) when lightly loaded.

Brian

 

[Delta Drifter]

Brian

Thank you for the info. I will try your way next time out.

 

[seaboarder]

Sportsman WOT and Props

My Yamaha shop says that my Sportsman w/ F150 should top out at 5800-6000 RPM at WOT. They said that if this is not the case then I have the wrong prop and it can decrease the life of the engine. In flat conditions I hit 5800 at around 42 MPH with trim tabs all the way up ( engine trimmed slightly ).

 

[JUST-IN-TIME]

Re: Sportsman WOT and Props

My Yamaha shop says that my Sportsman w/ F150 should top out at 5800-6000 RPM at WOT. They said that if this is not the case then I have the wrong prop and it can decrease the life of the engine. In flat conditions I hit 5800 at around 42 MPH with trim tabs all the way up ( engine trimmed slightly ).

perfect