Perfect prop for my 2007 2120 Yam F150TXR 4s

After 14 months of fooling around in my spare boat time with props, plates and trim tabs I finally have the right prop on my 2007 2120 Yam F150TXR 4s.

It is a Yamaha Reliance 14 1/2 X 15 three blade stainless I bought from Shortsmarine.com for $371.25. Yamaha part number 68F-45970-00-00. It was designed for the 150 4s.

In slick calm fresh water today with only me in the boat and 5/8 tank of fuel the WOT was 6,000 RPM, 38.6 MPH (GPS two way run) and 2.2 MPG with engine trimmed up and trim tabs in all up position.

Had some minor porpoising only when it was super slick calm water that could easily be controlled with minor engine or tab controls. Boat responded well under tight turns, backing, etc.

Boat came on plane in just over 5 seconds (estimate). Really stayed flat and jumped up on plane coming out of the hole with tabs and engine all down. My tabs are factory 12X12 Lencos with a lighted gauge.

After a number of runs I could see some variances in the Yamaha gauges, but I could see my sweet spot is anywhere between 4,000 and 5,000 RPM with a fuel burn of 3.0 to 3.3 MPG (about 300 max. mile range) running 20 to 32 MPH.

Today I settled in on 4,500 RPM 30 MPH and 3.2 MPG with my port tab down half way as a great cruise setting. Probably picked up some debris in the speedometer hole as another long run was 4,500 RPM 27 MPH and 3.2 MPG. I assume if the Yamaha speedometer is not accurate, neither will the MPG reading. Water was too cold to mess with the speedo hole cleaning.

I needed no tabs at WOT but at lower speeds I needed to trim the port side down. Suspect my weight and the fuel kept me listed to starboard.

At 4,000 RPM I needed all of my tabs to stay on plane and could go down to 3,800 or 3,900 but it took some attention to hold the 19.8 MPH.

I have 18X12 Lenco tabs at home I may or may not install now that I have numbers and control I like. Maybe if I get back on my trailer one day. My engine is mounted in the middle holes and it might be better up a hole but I could not check the cavitaion plate out alone today.

My boat came with a Yamaha 14 1/4 X 16 ss 3 blade that would never touch 6,000 RPM and I had porpoise problems at high speeds. I had the blade cupped and it worked better but I maxed out at 5,500 RPM. I tried a composite prop with adjustable pitch and it did not compare to a ss prop. It makes an inexpensive spare and you can change out one blade at a time.

I tried the CoBra ss plate and a plastic plate but did not like the way the boat would snap into a turn at speed although they did help jump on plane and helped keep the bow down. I also moved 100 pounds of lead bars from the bow to other positions and just wanted to not have the lead aboard for the life of the boat. I weigh enough already.

No plates or lead aboard today and not much tab usage.

So, happy day and good to be out in Febuary in the sun and high water after the storms here in Nashville. ...........................Pete

Thanks for the data. I might run that prop to test as well. I have been running a couple of black steel props (15-1/4 X 15, 13-3/4 X17) and been fairly satisfied but I like to tinker also. I would like to try a 15-3/4 X 13 Black Steel first before I move to another line.

The black steel props are good for those days when the Admiral is driving and we dredge the oyster beds :shock:

For what it's worth I published test results on June 8 2007 and found that the 13 3/4 by 17 seemed to be a good prop for the 2120 compared to the 14 1/4 by16 and 15 1/4 by 15. Although top end was about 5500rpm the speed by gps was essentially the same as your result at 6000rpm and the Mpg and speeds at other rpms seems a little better. In any event I spoke to Eric at Parker a month or so ago and he plans on running tests with the 14 1/2 by 15 reliance prop and will let me know the results. I'll pass them on.

Ray

The Reliance prop was suggested to me by a Yamaha engineer who said it was specifically designed for the 150. He also said it was probably better to turn up 5,700 to 6,000 RPM so the engine would not lug or be loaded up. I was okay at 5,500 with my cupped prop, but feel more comfortable being able to touch 6,000 but not exceed it. Here is some info from the Yamaha site:

Reliable performance Yamaha’s new Reliance™ Series propellers provide excellent performance with engines up to 300hp. An all-new blade design delivers more speed at all rpm’s, excellent anti-cavitation, and better grip for added bow lift and top-end speed than our Black Steel propellers. Overall handing and turning is significantly enhanced.
Reliance Series Propellers

.................Pete

Looks like Yamaha only recommends the 15" pitch on motors of 200hp and up. Might want to look further into this suggestion.

http://www.yamaha-motor.com/outboard/po ... r_Desc.pdf

My 2100 deep vee CC with F150 came from Parker with a 15-1/4 x 15 black stainless prop, and I am very pleased with it. I get 6000 rpm with three and gear aboard, and just a hair over 40 mph. At 4000 rpm, I get about 27 mph, and am burning under 7 gph.

I'm not sure a different prop would do anything for me.

The Yamaha specs on the Reliance props have no HP restriction on the prop use on their site under the 68F-45970-00-00: http://www.yamaha-motor.com/outboard/po ... 50_300.pdf

Do not know why they state what they do about HP on another page on their site. Maybe because this Relaince prop is relatively new in their product line?

After all my experience with different props, weight distributions and hydrofoils I find the prop Yamaha selected for my 2120 F150 4s to be perfect. I want to touch 6,000 RPM; come out of the hole with only the motor trimmed down; have good handling characteristics in tight turns; have an acceptable sweet spot band for fuel economy; etc. and the Reliance 14 1/2 X 15 gives me all of that. I have some hours on it now and it is like handling a different boat - one that reponds well under a variety of conditions.

I have no experience or suggestions on the 2100 CC props although it looks like the 2100 may be 500 pounds lighter than a 2120 and have a different center of gravity without the forward pilot house.

Could be other props may give more WOT speed or pop up quicker or satisfy other specific desires of 2120 owners, but this is one happy 2120 camper here to finally have what I was looking for....................Pete

I need a prop with that performance.

purchased same reliance prop and installed last night. I cannot believe the difference prop made in the performance and handling of my 2120 .

Can you swap for the same diameter and pitch, or do you need to adjust due to the performance changes ?

My guess is that it will not be an identical swap, but of course depends on how close you current prop is to what you want. If you have the figures on your current performance, then you could call Yamaha direct as I did to get a suggested prop. You could also use a good prop shop. Depending on what prop you have now, you may have to compromise on a size anyway since not all props come in all sizes.

I was close to what I wanted with a standard Yamaha 14 1/4 X 16 but the Reliance 14 1/2 X 15 certalinly performs much much better even though it is very close in designation. .............Pete

whats the best prop for a 150 2s ??? on a calm day 4300 rpm gets me to 30 mph...
dave

What was the GPH in the sweet spot? I guess I can calculate from the MPG to get close but would like to know what you got. I have the same boat and was thinking about getting a new prop. You convinced me.