2120 sport cabin with 150 2 stroke Yammy performance

[captnick]

I'm looking for performance numbers for a 2120 sc with 2008 Yamaha 2 stroke 150. I found them for the 150F but would expect the 2 stroke to burn more fuel and of course oil. Looking at a used 2120 in nice shape but with a 2 stroke.

 

[MadGar]

Captnick, I do not have performance numbers for that setup however I do have a 2008 Yamaha 150 2 stroke (non-HPDI) on a 19' Kencraft CC. The motor is outstanding and surprisingly will not burn as much fuel as you would think. No, it is not as economical as the 4 stroke F150 nor is it as quiet (but not stupid loud either), but it is a highly reliable motor that will not break your wallet on fuel and will probably push that boat noticeably better than the 4 stroke. If the price is right, go for it.

On a side note, I use only AMSOIL 2 stroke oil in my 2 strokes and after you start the motor the normal smoke associated with 2 stroke is not noticed or smelled. It surprisingly burns less oil than you think. In my opinion, great motor however some just despise 2 strokes but that should enable you to negotiate the price down. Good luck

 

[Sully]

I have a 2003 HPDI 200 Had it since new I love it I have used Amsoil two stock HP oil since day one love it no smoke or smell

 

[captnick]

Thanks for the replies. After my experience with the 2004 225F I really don't have a problem going back to a 2 stroke especially with low hours.

 

[Wet Willie]

This is a 2000 175 2 stroke carb. on a 2110 which is the same hull as the 2120 but a walkaround vs. a pilot house. Probably pretty close to what you would see. This pic was taken running upwind in approx. a 2 foot chop. EDIT: Sorry, i tried to download a pic showing my fuel burn according to my Garmin GFS 10. Basically, it showed 2.39 mpg at 24.9 mph. It can do a little better on calm water. I know it's not the exact combination in question but I hope it helps.

 

[DSW]

Hi,
Wet Whille what RPM do you get the best mpg? I have the same 2110 with a 175 carb, but don't have a fuel flow meter. I recently changed props from a 17M to Q3 15 x 15 recommended by ken at propgods. I like the 15x15 it gets on plane quicker at 3400 verses 4000 for the 17m, Similar high ends of 39, so far only better performance with the Q3 15.

What RPM to you recommend to get 2.39 mpg and what's the corresponding gph? Thanks for the help.

 

[Wet Willie]

Hi,
Wet Whille what RPM do you get the best mpg? I have the same 2110 with a 175 carb, but don't have a fuel flow meter. I recently changed props from a 17M to Q3 15 x 15 recommended by ken at propgods. I like the 15x15 it gets on plane quicker at 3400 verses 4000 for the 17m, Similar high ends of 39, so far only better performance with the Q3 15.

What RPM to you recommend to get 2.39 mpg and what's the corresponding gph? Thanks for the help.

I JUST installed the fuel flow meter a couple weekends ago and have only ran the boat that one short afternnon where I got the readings I passed along to ya'll. That afternoon I just went out for a short ride to confirm operation of the newly installed flow meter and my son wanted to take a nap in the cabin so I was looking more for a comfortable ride than top MPG. If weather permits I will get the boat back out this coming weekend and give you more info. I will say that the MPG improved to 2.5 something at one point when I went a little faster but the ride got bumpy so I backed it back down because of my son being up front. I too am running a 17p black steel 3 blade Yamaha prop and have been thinking about changing props to see if I can get a lower planing speed and better economy when it's snotty out. I will be bck in touch and look forward to your feedback on your prop change as well.

 

[DSW]

Hi,
Here are my prop number on a 2110 with a 175 carb.

Old Prop
17M RPM Speed Slip
4000 27
5300 38 17
on plane 4000

New Prop
Q3 15p RPM Speed Slip
1000 4.4 45
2000 7.7 49
3000 11.8 49
4000 25.1 19
5000 34.8 8
5500 39.0 7
on plane 3400

I like the new prop better, on plane sooner and same top end.

 

[Wet Willie]

Hi,
Here are my prop number on a 2110 with a 175 carb.

Old Prop
17M RPM Speed Slip
4000 27
5300 38 17
on plane 4000

New Prop
Q3 15p RPM Speed Slip
1000 4.4 45
2000 7.7 49
3000 11.8 49
4000 25.1 19
5000 34.8 8
5500 39.0 7
on plane 3400

I like the new prop better, on plane sooner and same top end.

Thanks for the info! I do like those numbers alot better for my purposes. I was looking for something that would allow me to hold plane at a lower speed for economy / comfort when it's snotty out on those days when the wind picks up and I'm 40 miles from the house. That prop just might be the ticket for me. I can imagine I would see a huge difference in economy at 20 mph or so with the Q3 vs the 17 I have now. Thanks alot for the help, and I will be back in touch after the weekend (weather permitting, right now they're calling for T-storms here) with more detailed info. from my flow meter. Thanks again for your help, I will return the favor.

 

[Wet Willie]

DSW, sorry I've been so long getting back to you with the numbers you requested. Weather and family obligaions prevented me from geting out on the water for two weekends but I finally got out on Saturday. According to my Garmin fuel flow meter and running my 17P prop. I am cruising 25 MPH at 3,800 RPM and getting about 2.4 statute MPG. My best mileage seems to come in at 4,000 RPM and 27 - 28 MPH gettting right at 2.5 MPG. At 20 MPH I come in at 2.0 MPG. I hope this helps you sir.

 

[DSW]

Thanks for the update. I've heard people say 4,000 rpm is the best mpg for these 2 strokes, so your numbers show that's true.

How did you run the cable for the fuel sensor? Did you run it in the rigging tube and was that easy to do?

I just got a Permatrim and when I get a change to test it I'll post what I learn. Thanks for your help. I'm learning a lot on this site.

 

[DSW]

PS- Do you know what your GPH is at 4,000 rpm?

 

[Wet Willie]

Thanks for the update. I've heard people say 4,000 rpm is the best mpg for these 2 strokes, so your numbers show that's true.

How did you run the cable for the fuel sensor? Did you run it in the rigging tube and was that easy to do?

I just got a Permatrim and when I get a change to test it I'll post what I learn. Thanks for your help. I'm learning a lot on this site.

The fuel sensor is a fairly east install but it does require a NMEA 2000 network. I installed both the NMEA 2000 network and the fuel sensor at the same time. Basically, I needed to run the NMEA 2000 backbone cable through the rigging tube from the starboard jump seat to the helm and power it through my fuse panel. I also ran the power wire for the fuel sensor through the rigging tube to the helm so I could power it from my fuse panel because I do not have a bus bar in the stern. If you have a bus bar in the stern this would not be necessary. The "signal" wire from the fuel sensor connects to the NMEA 2000 backbone cable up under the starboard jump seat, and the display connects to the other end of the NMEA 2000 backbone cable up under the helm. Other than that you just mount the sensor where you like and "T" it into your fuel line between you fuel tank and primer bulb. It also comes with a little filter to install before the sensor but I chose not to use this because my fuel passes thru my Racor before getting to my sensor so I felt it was unnecessary. The fuel flow meter can be set to show statute MPG, nautical MPG, or GPH. It is really cool and I feel it was a good investment. If my description of the install was not clear enough to answer your questions, Garmin has install instructions for the GFS-10 and the NMEA 2000 starter kit on their website. If you have any more questions please feel free to ask, I will be happy to help! As far as GPH at 4,000 RPM, I did not set the display to show me that while I was running, but if I did my math properly it calculates out to around 11 GPH.