Fuel consumption

Dale Benson

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Grand Rapids, MN
What might the relative rate of fuel consumption be between a Yamaha 50, a 115, and a 150, given the same type of usage over a season? Usage would likely be mostly cruising and fishing, so a lot of fairly slow moving. My current set up is a Yamaha 50 but I'm looking to order a whole new outfit and just wondering about tradeoffs in going BIG. Mainly it's coming down to either a 115 or 150. If I went with the GFS model with SPS package and a Yamaha 150 SLO, how might that negatively impact how I currently use my rig (that is, slow cruising with a couple of other passengers, and fishing). It would be over-kill, I realize... but might there also actually be negative implications?
 
In my experience, the more fuel I put in my boat, the more fun I have. Your mileage may vary.
 
In my experience, the more fuel I put in my boat, the more fun I have. Your mileage may vary.

Randy, Thanks for the feedback. I should have been clearer with my question. I'm not so much interested in how to get more fun out of a new rig as much as I am in learning the differences between what to expect from the different size motors. Someone using a 150 to mostly tow skiers and tubers is (obviously) going to use more fuel than someone with a 50 mostly using it to cruise and fish at slow speeds. But what I'd like to get input on is anyone's experience (or educated guess) using different motors for the same things. My current rig - a Yamaha 50 on a 2007 22 FSI, is a the largest motor I've had. I would assume that a 150 will use more fuel than a 50. But how much so? 10% more? 50% more? Even "not much difference", or "a LOT more" would be a useful answer if anyone is able to provide. And same question regarding the 115.

Another consideration I wonder about is minimum speed. How hard would it be to get a 150 down to trolling speed? Would the use of a drift sock be sufficient to get down to say, 2-3 mph?

Would the additional weight of a 150 cause the profile of a 22 GFS to be bow high setting in the water? Would adding the SPS package help to keep the profile of the boat more level to the water? Would a SPS set-up cause me to set deeper in the water, or shallower?
 
Last season I used about 75 gallons for 50 hours
 
We float along the shoreline all the time with guests and our boat just sips fuel at that rate. A 150 on an SPS will sit a little lower in the tail but the SPS will sit higher in the water overall than a twin log boat. For my use I’d never consider the 115 as I’d rather jump to the 150/SPS, it such an awesome package to use plus resale would be considerably more. My buddy fishes off his triple toon with a 300 on the back and runs it hard to where he wants and idles along to fish, his excuse for the hp is so he’s not late for dinner! :)
 
Randy, Thanks for the feedback. I should have been clearer with my question. I'm not so much interested in how to get more fun out of a new rig as much as I am in learning the differences between what to expect from the different size motors. Someone using a 150 to mostly tow skiers and tubers is (obviously) going to use more fuel than someone with a 50 mostly using it to cruise and fish at slow speeds. But what I'd like to get input on is anyone's experience (or educated guess) using different motors for the same things. My current rig - a Yamaha 50 on a 2007 22 FSI, is a the largest motor I've had. I would assume that a 150 will use more fuel than a 50. But how much so? 10% more? 50% more? Even "not much difference", or "a LOT more" would be a useful answer if anyone is able to provide. And same question regarding the 115.

Another consideration I wonder about is minimum speed. How hard would it be to get a 150 down to trolling speed? Would the use of a drift sock be sufficient to get down to say, 2-3 mph?

Would the additional weight of a 150 cause the profile of a 22 GFS to be bow high setting in the water? Would adding the SPS package help to keep the profile of the boat more level to the water? Would a SPS set-up cause me to set deeper in the water, or shallower?
I have a 24sfx with SPS and Mercury 150, I primarily fish and cruise. I had a 2275 fsi with a 90 HP prior to buying this boat. My 150 trolls at approximately 2 mph, the fuel difference between the 90 and 150 is about 10-15 % more for the 150, but I do get around the lake alot quicker and with alot less effort. My new tritoon rides a little higher yhan my old one but not enough to worry about.
 
My new tritoon rides a little higher yhan my old one but not enough to worry about.

So, to clarify in my mind, you can still get up into just as shallow water (or maybe even shallower?) than without the SPS package? And on the other side of the water line, you are reaching down a bit further to net your fish? :) Is that correct?
 
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Randy, Thanks for the feedback. I should have been clearer with my question. I'm not so much interested in how to get more fun out of a new rig as much as I am in learning the differences between what to expect from the different size motors. Someone using a 150 to mostly tow skiers and tubers is (obviously) going to use more fuel than someone with a 50 mostly using it to cruise and fish at slow speeds. But what I'd like to get input on is anyone's experience (or educated guess) using different motors for the same things. My current rig - a Yamaha 50 on a 2007 22 FSI, is a the largest motor I've had. I would assume that a 150 will use more fuel than a 50. But how much so? 10% more? 50% more? Even "not much difference", or "a LOT more" would be a useful answer if anyone is able to provide. And same question regarding the 115.

Another consideration I wonder about is minimum speed. How hard would it be to get a 150 down to trolling speed? Would the use of a drift sock be sufficient to get down to say, 2-3 mph?

Would the additional weight of a 150 cause the profile of a 22 GFS to be bow high setting in the water? Would adding the SPS package help to keep the profile of the boat more level to the water? Would a SPS set-up cause me to set deeper in the water, or shallower?

Yeah, I was just being a smart ass! Having owned a 115 and now a 150, I would NEVER recommend a 115 for a performance or fuel economy upgrade. I don't keep track of my fuel consumption (hence my earlier flippancy) but I really didn't see my fuel usage increase when I went to the 150. If anything, the 150 doesn't have to work as hard as the 115, in my experience. IMHO, the 115 is a compromise engine that doesn't really satisfy. I have, however, seen feedback from those with the new 115 Command Thrust version that are very pleased with their choice.

I don't fish, but do spend a lot of time at trolling speeds on sunset cruises and find the 4 stroke idles right down and doesn't display any of the smoke or misses that I remember from the old 2 strokes. Again, 2 stroke technology has really improved, so maybe not a fair comparison.

I'm unclear as to why you are looking at anything larger than a 90 if you are primarily going to use the boat to fish. Are there other activities (tubing for example) that you are anticipating? I guess I need more info. I am a huge fan of the 150/SPS, but I'd never try to talk someone into it if they had no need for it.
 
We went from a 2 stroke 90 to the 150. Most our our time is spent cruising at low speeds and we don’t see a significant increase in fuel consumption. Now tubing is a different story but not as much as you might think. Sorry, can’t provide any numbers.
 
I've kept detailed records of hours, fuel and activities, and I was pleasantly surprised that my 150 used less gas than my 115. The 115 ran wide open when tubing, the 150 runs about half throttle for the same tubing action.

You can find fuel consumption curves on the Mercury website with test data for different motors and different boats.

5 mph no-wake speed is about 1200 rpm on my 150. It idles at 600 rpm. I don't know what idle speed would be at no wind since the wind always blows around here. I'd guess 2 mph at dead wind, idle speed.

Mercury Prop Selector: https://www.mercurymarine.com/en/us/propellers/selector/#!/step-one

You can enter Yamaha engines here too.

Test Sheets: https://www.mercurymarine.com/en/us/performance-tests/outboard/

There are a handful of Benningtons on here, but you can look at lots of other pontoon boats. Select "Bennington" under the "manufacturer" tab. Then click on the 150. Scroll down to see the red curve in the graph at the bottom of the page. This gives you the fuel consumption for various RPMs.

You can try to find a 115 on another boat brand (I don't see one on a Bennington), or try to find the same boat with test sheets for the two engines you are looking at (even if they are not Benningtons). That way you can compare the relative difference between the engines.

I looked through tons of these several years ago when I was looking to upgrade to the 150. What I remember is the fuel consumption curves don't vary a lot (all pontoon boats are similar, for example). The trick is to find the MPH that you most cruise at on two identical boats (hulls more specifically) with whatever engine sizes you are comparing. Then you can tell how much fuel you will use, and which engine is the most economical at that speed. I hope all that makes sense. Start snooping around on that second link. You'll probably find what you are looking for.

If you have questions, just ask. I've got nothing to do until boating season starts.
 
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Ditto above comments about SPS/Tritoons/150hp. What I would add is below —>

Fuel consumption is tricky sometimes due to various factors: weight, hull type, motor, weather conditions (wind/waves/drag), etc... This was something I was curious about last year when considering a 150/200/250.

Below are two resources that may be of help if just curious, or if making a concrete decision.

The first one is an interactive fuel consumption calculator. You need to pick from the various categories, and then dial it in (motor-manufacturer/HP/RPM) and it gives projected fuel consumption. It covers a very wide range. I really liked using it last year as it gives you fuel consumption over the entire arc of a motors performance. Check it out. I think you will really like it based on your main question.

http://www.boat-fuel-economy.com/outboard-fuel-consumption-us-gallons

The second is an article with the formulae’s to calculate fuel consumption for boat motors - both diesel and gas. Being non-mathematically minded, I have not personally applied it or cross referenced it against the above interactive resource. However, for those that like crunching numbers, I would think this is a nice resource for predicting fuel consumption:

https://www.boatingmag.com/calculating-fuel-consumption
 
Those are some cool links Jeff! I looked at the first one, and that is what I remember on my 115 and 150. My 115 used about 11 GPH at WOT. The 150 uses about 14 GPH. But, the 150 doesn't work as hard at any given MPH, and it goes a LOT faster than the 115 at WOT, so the top end GPH isn't really apples to apples (since you will be going a lot faster with the 150 at WOT). That's where the test curves come in, because they show the MPH printed on the same graph as the GPH (so you can compare GPH at the same MPH that you cruise at). That is, if you can find your boat. You should be able to find one similar though.
 
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This is great input, guys. Thanks very much. I'm really not looking for real specific numbers. Mostly I just want to be aware of the practical differences I should expect with various set-up options. Our first inclination is usually that "bigger is better", with cost perhaps being the limiting factor. But I want to make sure I've considered all the consequences besides cost. If I order the tri-toon package, for example, I'd like to know ahead of time that landing a fish from a higher perch will be a consequence to deal with, or that the boat will be setting so much lower in the water that I can't get back into some of the places I could with the previous one. Or that a 150 will idle too fast to troll or run too loud to converse comfortably with passengers, or requires that I haul in extra
cans of
fuel to the cabin.
I think I'm pretty clear about most of the amenity options. Mainly I would like to get input about considerations regarding the difference between the two tube and three tube set-ups as related to my expected use (that is, cruising and fishing), and the differences between the 50 (which I'm familiar with) and a bigger motor up to a 150.
For my intended use of fishing and cruising (there will never be any skiing or tubing), then I really can't see that I'll NEED anything much bigger than a two tube with a 90 or 115 HP motor. But if I DID for some crazy reason pull the trigger on a SPS package with a 150, what might be some unforeseen consequences (as relates to my intended use)?
Again, thanks very much. Plan to call in the order next week.
 
I wouldn’t worry about the added bow heigh for landing fish from a tritoon. I’ve landed many bass and pike from mine. I’ll be pulling saltwater species on it soon enough
 
Based on your additional info, I would think a nice 2 tube boat with a 90 4 stroke would be ideal.

Unless you are looking to sell in a couple years, I can't imagine why you would want to spend the extra cabbage on a 150/SPS boat. It would have better resale, but the cost of admission won't be cheap.
 
If you just want to fish and cruise, just get a small motor and two tubes and save the money. Or put the money towards amenities above the deck.
 
Three tubes will give you less draft, but your talking a couple inches. Unless you're after minnows, you probably won't notice the difference.
 
Forgot noise. My 150 is quieter at idle. One thing I didn't realize until after I got the 150 was how much the boat vibrated with the 115. It wasn't terrible, but you could definitely tell the motor was running. You could feel it in your feet and butt. The 150 is silky smooth. And it is hard to tell it's running unless it's dead calm out. It is very quiet. The 150 is in a totally different class.
 
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