how hard do you run your boat

[head fixr]

I have a 2005 210cc with a yamaha F150. When the weather and swell are nice i will run at 4900rpm @ about 35 mph sometimes for an hour. Is that ok or should I slow down. I get the best fuel milage @ 4200rpm.

[jergofish]

My 2006 215 only has 75 hours on it. I also installed a fuel meter (Lowrance 337c with EP-10 fuel meter, NMEA 2000 system) when I put on all my electronics. I stay below 4000 RPM with my Suzuki 175 most of the time since, when I boost the throttle past that I can watch the gallons per hour climb from six to sixteen! 3800 RPM gets me 28mph and that's fast enough anyway. Beyond that the ride starts to suffer unless I'm on really flat water, even with my big trim tabs.

[special K]

I'll be honest with everybody, I do not know what my best cruising speed is or my gas mpg. I really have a short trip from my ramp to my fishing grounds, usually about 5 miles over all. I will drift most of the day, if I hit a spot I will circle around and fish it again. If I use a 1/2 a tank(21gl. 170cc) it's been a bad day of fishing. Am I doing something wrong, Should I know these figs. I will get to where I have to in a hurry WOT. but on the way in I usually go nice and slow putting in a Jimmy Buffet CD and reflect on my day of fishing and how lucky I am to live in FL.

[Putershark]

Most all of your modern engines both 2 and 4 stroke all return their best performance for range from 3000 to 4500 RPM. Above 4500 you are most times just burning a lot more fuel for very little return in speed and usually take a huge hit in range.

That being said, you still need to run your engine at or near WOT for some time before shut down to remove the moisture from the oil. If not, that moisture turns to an acid that is very hard on engine parts while you have it parked back at the house.

Though somewhat off of this subject some, here is a thread on oil use that may better explain why you should run your engine for some period of time at high RPM on each trip out Synthetic Oil

Now I usually run mine near WOT for a mile or so on my trip back to the ramp every time out but no, other than burning a lot more fuel during such runs, it does not hurt them to run them at high speed... Matter of fact if the engine is still under warranty and in it's post break in period, it is even better for if it is to come all unglued, that is when you want it to happen for sure

As far as max range goes, all things being equal usually the lowest speed that you can run and the engine still keep the hull on plane (without lugging the engine) will bring you your best range. Without a fuel burn gauge installed about the only thing you can do is track how many gallons of fuel you burned at each fill up / by the number of engine hours ran on that tank. Though rough, you can still see a pattern develop over time and tell much faster when you are in need service work, fuel brand and or octane change, etc... That is why we have some simple fuel burn rate Excel Sheets posted to help everybody track such.

Enjoy!

[head fixr]

thanks for the input i was just wondering if i am to hard on the motor. I fish morro bay CA. so the conditions usually only allow for about 25 mph

[jergofish]

Putershark, if it's known that the moisture in the oil turns to an acid that corrodes the engine, why isn't there a marine formulated 4 cycle oil that will combat this problem. If produced in large quantities, economy of scale would probably increase the price by pennies.

I guess the other choice is frequent oil changes or, as you say, WOT runs.

[Putershark]

There is and the other threads went in to that some...But both Petro base and Synthetic base stocks that are "marine grade" oils have higher additives to help prevent this acid build up and they are known as "anti rust additives" and here is one example of such
http://www.amsoil.com/StoreFront/wcf.aspx
with the critical thing being that even with the better synthetic based oils, you still have about the same drain intervals which is wise to help reduce this threat...

Generally speaking though, you need to get oil above 180 degrees to boil off this extra moisture that marine engines have to deal with on each intake stroke, and that is why some high RPM time before shut down is wise