How long can I run 15HP outboard continuously?

dlochner · Sep 8, 2020

Assuming the water pump is working, until you run out of gas.

Ken Cross · Sep 8, 2020

Powerboats run them continuously.

Ken

rgranger · Sep 8, 2020

kjdoyle1 said:
We have a 1998 Johnson/Evinrude 15HP (J15RLECR) that is in good shape on our Catalina 25. We usually run it for about 20-30min at a time until we can set sail. However, we would like to cruise through NYC and plan on needing to be on the motor for awhile (at least through East River, probably more).

I am wondering how long we will be able to run the motor continuously. Any thoughts?

-Kyle

All snarky comments asside...(although I enjoy snarky) I assume you are asking for advice on ways to determin how long you can run your motor on a tank of gas.

I would empty out your gas can, then put a quarter gallon or less in and then run it in gear at 2/3 throttle until it runs out of gas. Time it and see what you can do on 1/4 gallon. Then fill up your tank and see how many quarter gallons you hold and figure if you run at half throttle instead of 2/3 you have at least that much time per tank (or gallon or what ever you like best).

Captain Larry-DH · Sep 8, 2020

All of the above. I’d get an extra tank, unless you don’t have a long term use for it. Do you have a friend or slip neighbor who would lend you a spare tank? You would need to have the right fuel hose connector, but if it’s an aftermarket tank you can buy a proper tank connector for a lot less than the whole setup.

PaulK · Sep 8, 2020

Going up the East River you need to time your transit to go with the tide/current. This cuts how long it takes a lot. On our last transit we passed Hunt's Point doing 13 knots over the bottom according to the GPS, though we were only doing something like 7 through the water.

dlochner · Sep 8, 2020

As someone who might have given a "snarky" reply, let me clarify. I understood the question to be about running the motor for long periods of time and if it would damage the motor. So, answers along the line of "so long as you are feeding it gas, it will run" are in line with the question.

On the other hand, if the question is about how many hours can the motor run on X gallons of gas, the answer I gave was kind of snarky and off base.

Motors built for marine use are generally designed to run long and run hard.

Ron20324 · Sep 8, 2020

kjdoyle1 said:
...we would like to cruise through NYC and plan on needing to be on the motor...

They probably will not appreciate all that noise in the theater district or Broadway!

Joe · Sep 8, 2020

If it were me and was I simply wondering about what kind of reliability and performance to expect with a 20 year old motor that's been adequately maintained, I'd take pay a professional mechanic for a check up and diagnostic report. If I had no idea the level of maintenance from previous owners.... I absolutely would have a professional look at it.... And once you decide to go... then you'll want to carry enough tools, spare parts and repair manual... just because you never know. Spares like fuel filter, thermostat, plug, oil change gear, etc. will give you some confidence.

dLj · Sep 8, 2020

Reading your original post it seems to me you are asking if that motor is designed to run for long time periods, like all day or so.

I've run outboards for entire days without a problem. I've done this for several days in a row. If yours is in good shape it should be fine.

It's your motor, so you should have some idea of how well it runs, does it start reliably? Has it been giving you problems? You need to answer those questions. If the motor is and has been reliable, go for it. Bring enough fuel, perhaps a spare impellor and know how to change it.

Enjoy the trip!

dj

Benny17441 · Sep 8, 2020

As long as you got gas. Strap a 5 gallon can to one of the stanchions and refuel when needed. We run an old 2 stroke 9.8 Nissan So we also have to mix in the oil when refueling our 3 1/2 gallon main tank. It burns approximately 1GPH. On a trip in the Long Island Sound one morning we started the engine and the starter cord broke, but since the engine was running we figured we would fix it at our destination. We had to take care that we refuel early so the engine would not die so we motor sailed and motored for about seven hours and before we left the boat at a mooring in Northport we had replaced the starter cord.

rgranger · Sep 9, 2020

Ron20324 said:
They probably will not appreciate all that noise in the theater district or Broadway!

Speaking of snarky....

Timm R Oday25 · Sep 9, 2020

Our pair of outboards that power our dive boat ,Mercuries have a warning not to run at full throttle for more than 8 hours of continous use . I would suggest learning how to replace your waterpump . Always carry a spare

Tim Mills · Sep 9, 2020

Use the Navionics app to find out exactly when slack tide is at Hell Gate and other locations and ride the current and plan your trip accordingly.

It wont take but a few hours to run up the East River from Wall Street into the LI Sound. its less than 20 miles.

Serenity on Hudson · Sep 9, 2020

I've worked on the East River in small motor boats and motored into Hunters Point at LWS in my H23.5 with a 9.9 hp Honda. If you are late to enter you may not come out! The currents are 7+ knots and they don't call it Hellgate for nothing. I've seen eddy's that would spin a 30 foot boat like a dinghy. Just running with the tide is not necessarily a safe passage. Slack tide in and don't dwaddle.

Mr Fox · Sep 9, 2020

Definitely get it looked over by a mechanic, I lived in NYC for 20 years and have taken many boats up down and around the Hudson/East River and LIS. East River is not a place you want to lose power. Make sure to use the tide to your advantage or you may be traveling at -2kts at full throttle!

Jackdaw · Sep 9, 2020

As long as they have clean gas and cooling water, forever. Not diesel forever, mind you, but a long time.

Benny17441 · Sep 9, 2020

Before you fill the boat with spare parts, get Tow Insurance coverage. A sailboat is an almost perfect Hybrid, no engine you sail, no wind call Tow BoatUS.