Merc 115 or 150 gas mileage

[lablazin]

Looking to get a new boat in the next 2-3 months. Looking at either Vexus AVX1880 or 1980, Or a Ranger RT188P or 198P. How does the Mercury ProXS 115 or 150 do on gas mileage? Kinda wanting to go with a 150, but if the difference between in mileage is huge between the 115 and 150 I may go towards the 115.

[Bill Reynolds]

I can’t help with the 150 but I consistently get 5.0 MPG on my 115 on RT188. my fishing style is short runs and I don’t troll. I normally drive about 4800-5000 RPM.

[Extremeboating]

4.9-5.0 mpg at wide open throttle on the 115's.

[Mechanic Bob]

Not sure on the fuel capacity on the AVX, but my 2019 RT198 P has a huge fuel tank and the 150XS is stingy on fuel. Don't know the MPG but I have made some very long runs in a given day, and never have fuel concerns.

[GeauxTide]

I have a 115 Optimax and the gas mileage is ridiculous. Typically burn 4-5 gallons for a full day. The four stroke, 4 cylinder 115 is also great on gas. Thing to consider is what boat do you want and the motor will follow.

[bassfisher444]

A 150 uses more fuel than a 115 running wide open, however a 150 running at part throttle will use less fuel than a 115 will running wide open at that same speed.

[Dmy-rt188p]

Per my VesselView, my 2022 RT 188P gets the following:
7.3 mpg at 3000rpms, 6.1 mpg at 4000, 5.4 at 5000 and 4.5 at 6000. That is based on 63.43 hours on the 115xs/ct.

[zaprod71]

I know budget factors, but i wouldn't let gas mileage determine which boat to buy. Get the boat that gets you as close as you can to want you want for size and extras. Maybe an 1880 with more goodies is more important to a lightly tricked out 1980? Maybe an extra foot matters for ride and fishing function so you go with the 198P?
Both engines will do great on fuel.

[n2ratfishin]

I know budget factors, but i wouldn't let gas mileage determine which boat to buy. Get the boat that gets you as close as you can to want you want for size and extras. Maybe an 1880 with more goodies is more important to a lightly tricked out 1980? Maybe an extra foot matters for ride and fishing function so you go with the 198P?
Both engines will do great on fuel.

Agreed, while my little 115 4S sips fuel compared to my last 225, that fuel is a drop in the bucket compared to the overall cost of bass fishing.

[bassfisher444]

I would get a boat with a Yamaha SHO on it instead of a Mercury, better performance all around.

[pabasshawk]

Fule consumption wouldn't even be a consideration when buying a boat unless it was an offshore boat with a 500 gallon gas tank.

[catdude28]

I know budget factors, but i wouldn't let gas mileage determine which boat to buy. Get the boat that gets you as close as you can to want you want for size and extras. Maybe an 1880 with more goodies is more important to a lightly tricked out 1980? Maybe an extra foot matters for ride and fishing function so you go with the 198P?
Both engines will do great on fuel.

Agree also. But bigger is usually better. More storage, space, and better in the rough stuff. Extras can be added later, but boat length can’t. Throttling back on the bigger boat with a 150 will likely get you the same fuel economy as running the 115 flat out on the smaller boat, and likely around the same speed.

[Johnnyred]

Agree also. But bigger is usually better. More storage, space, and better in the rough stuff. Extras can be added later, but boat length can’t. Throttling back on the bigger boat with a 150 will likely get you the same fuel economy as running the 115 flat out on the smaller boat, and likely around the same speed.

... and that strategy will put less wear on the motor as well. Better to run a 150hp at 4500-5000rpm as opposed to a 115hp at 6300rpm.

[Extremeboating]

... and that strategy will put less wear on the motor as well. Better to run a 150hp at 4500-5000rpm as opposed to a 115hp at 6300rpm.

They're little 4 bangers not V6's or V8's. They LOVE to rev.

[ChooChooSnakeMan]

They're little 4 bangers not V6's or V8's. They LOVE to rev.

I'm really not trying to start a fight but I see this comment all the time and have a hard time with the logic of it. Yes smaller engines rev to higher rpms than bigger engines, it's just physics. It seems to me that common sense would say that any device when run at the top of its allowed range will see a decreased life compared to running at a less stressful rate of operation. I would agree that the smaller engines have internals that weigh less so they may last longer at WOT than a bigger heavier engine but I maintain that a smaller engine will live longer if it is usually operated in the sweet spot of its cruise rpm range compared to the same engine operated mostlly at WOT. Just less wear and tear on the engine. My opinion concerning the OP's question is, there won't be much difference (total $$$ spent for fuel in a years time) between the 150 and the 115 but the 150 will push the boat at normal speeds easier the 115 and have a higher top speed and cruise speed for when you need it. I'd get the 150 if the extra $$ are there for the purchase. Resell will be better, performance will be better and as stated your fuel cost won't be much different.

[lablazin]

Thanks for the advice guys. Just having a hard time deciding. I would love a bigger boat with the 150. Just some things i'm thinking about. Down here in the delta with tidal water sometimes you have have to go through some areas with less than a foot of water, so thinking about the weight of the bigger boat getting in there. Sometimes during the summer you have to make some long runs to get to a area with moving water when the water temps get hot. And also towing weight.

[Johnnyred]

I'm really not trying to start a fight but I see this comment all the time and have a hard time with the logic of it. Yes smaller engines rev to higher rpms than bigger engines, it's just physics. It seems to me that common sense would say that any device when run at the top of its allowed range will see a decreased life compared to running at a less stressful rate of operation. I would agree that the smaller engines have internals that weigh less so they may last longer at WOT than a bigger heavier engine but I maintain that a smaller engine will live longer if it is usually operated in the sweet spot of its cruise rpm range compared to the same engine operated mostlly at WOT. Just less wear and tear on the engine. My opinion concerning the OP's question is, there won't be much difference (total $$$ spent for fuel in a years time) between the 150 and the 115 but the 150 will push the boat at normal speeds easier the 115 and have a higher top speed and cruise speed for when you need it. I'd get the 150 if the extra $$ are there for the purchase. Resell will be better, performance will be better and as stated your fuel cost won't be much different.

You read my mind! Could not have said it better.

[Mechanic Bob]

Thanks for the advice guys. Just having a hard time deciding. I would love a bigger boat with the 150. Just some things i'm thinking about. Down here in the delta with tidal water sometimes you have have to go through some areas with less than a foot of water, so thinking about the weight of the bigger boat getting in there. Sometimes during the summer you have to make some long runs to get to a area with moving water when the water temps get hot. And also towing weight.

I too run some skinny water with my rig. Only problems are getting up or coming off plane, but that is Skinny water fishing!

[lablazin]

I too run some skinny water with my rig. Only problems are getting up or coming off plane, but that is Skinny water fishing!

Bob how shallow will that boat float?

[n2ratfishin]

I had my RT188 115 ProXs 4S out yesterday. My Smart Craft read 10.5 GPH burn rate at WOT (5900 RPMs) and 48 MPH GPS, livewell full and 1/4 tank of gas with full load. Typically an outboard will burn about the first two numbers of HP at WOT per hour. IE, count on a 150 burning about 15 GPH, a 200 burning about 20 GPH etc... Obviously hulls make a difference but it's a good guide to burn rate.

I agree with max HP but I have ran a couple with less. My Cat Cougar had a 225 Opti and my Sabre originally had a 150. The Sabre really woke up with the extra 25HP when I swapped for a 175. Let's be real, most of us don't run WOT everywhere. Most boats that came in when I worked at a dealership only had maybe 10% of total hours at WOT.