Wide Open

[Uncle Dave]

I observe most boaters with outboards running at wide open throttle.<br />Inboard outdrives seem to throttle back a good bit less than wide open.<br />Is it because IO/OD will not take wide open for sustained periods. <br />Thanks,<br />M.F.

 

[DJ]

Re: Wide Open

Mr. Fitz,<br /><br />Your thinking is partly accurate.<br /><br />I/O, inboards are based on automotive engines. For the most part, they were not designed to run at wide open throttle, uphill, all of the time.<br /><br />Secondly, many I/O's are of significant displacement and horsepower/torque. There is no need to run WOT to maintain a good cruising speed.<br /><br />On the other hand, many outboards are too small for the rigs they are on. Not always true, but quite prevelant. I have always spec'd my boats at 75%, or better, of their maximum rating.<br /><br />Outbnoards, being mostly 2-stroke engines, are quite comfortable running at WOT, or near it.<br /><br />Regardless of the powerplant, running at 2/3 to 3/4 will sve a signicant amount of fuel. As long as, the engine is capable of holding the boat on plane at that desired throttle setting. Two stroke outbaords cannot stand to be lugged.<br /><br />I will also add that perception is not always reality. Two stroke outboards, by nature of two power pulses per rpm., sound like they are turning faster than they may be in reality.

 

[Uncle Dave]

Re: Wide Open

Thanks Djohns<br /><br />So are you saying that an IB/Ob will have a short life if run often at WOT?<br /><br />Mr. F.

 

[DJ]

Re: Wide Open

Mr. Fitz,<br /><br />In my opinion-yes. Let me qualify that.<br /><br />Any engine that is run wide open, all the time is going to suffer. I can see no reason to do so unless one is an absolute speed freak or the engine is woefully inadequate.<br /><br />I have seen and operated many I/O's that were approaching 2000 hours. However, they were meticulously maintained and operated responsibly. The same holds true for outboards.<br /><br />Marine engines very rarely fail due to a true mechanical breakdown or defect. They die of neglect and poor, or, no maintenance.<br /><br />If you are looking for a new boat, follow the general 85% rule and you'll be pleased with the performance. Fall for a so called great deal, with a small engine andf you'll be unhappy and the powerplant will be troublesome.<br /><br />Remember, the engine is usually the most expensive part of a boat package. Dealers and manufacturers alike frequently use "price leaders" that are marginally powered.

 

[Bondo]

Re: Wide Open

djohns19,<br /><br />Well Said.......<br /><br /> They die of neglect and poor, or, no maintenance. <br /><br />Sooo True......

 

[frankdel]

Re: Wide Open

I owned a 1978 25ft Bayliner Saratoga with 228hp mercruiser I/O. Only time this boat saw WOT was to get up on plain and an occasional sprint. Im a firm believer to keep the RPM's down. 3000 RPM's was a good cruising speed of 28 mph for that boat. That engine was a perfect match for the boat IMO.

 

[Uncle Dave]

Re: Wide Open

Thanks to all for some good answers about Wide Open.<br /><br />Mr. Fitz. and the Miss Fitz