Running wide open

[Deenniiss]

Im headed to Branson on Lake Tanneycomo on the fourth . This will be my boats second trip to home away from home. I was wondering is it ok to run my motor wide open. It runs good wide open. Its a 1957 Evinrude 18 horse so I dont want to hurt it . Ive only had it 2 months and Im new to boating. It got up to 27 mph the last time out. <br />Also, it sounds loud. I know that the newer motors are not as loud but it seems loud to me. Is there something I can do to get it quiet.

 

[mylin]

Re: Running wide open

I race stack cars and I know alot about engines in general. Its okay to run an engine wide open but its more okay to run it just shy of wide open. Don't get me wrong you can see how fast she will go and have fun but if you plan to ride awhile it will always be better to lay off just a little. More rpm more stress in the engine. Hve fun this weekend

 

[fireman 757]

Re: Running wide open

As long as your mixture is right and you are cooling well it shouldn't hurt it. I've run my 1957 35hp jonnie wide open for the last 15 years for at least two hours at a stretch (commercial fishing the Ohio river) and I haven't had any problems.

 

[steelespike]

Re: Running wide open

Dennis,It has been a long time but if I remember right the max speed rating on a stock 57 18 was 27 mph. So even allowing for some error your motor must be pretty sound.<br /> I still think that with that age I would run<br /> a little off full throttle when running a long<br /> haul.<br />These motors were built with an intake silencer<br />on the carb if yours is missing that may account for some of the loudness.<br /> Also there are rubber mounts that if worn may<br /> allow the motor to transfer vibration to the boat. <br /> Enjoy your motor

 

[Forktail]

Re: Running wide open

Actually, carbureted 2-strokes usually run safer wide open than slightly back from wide open. This is because the main fuel jet is providing full fuel to the air mixture which keeps cylinder temperatures down. The fuel actually cools the cylinder. Slightly off from wide open usually meters the fuel leaner, because a carburetor is not a perfect fuel/air metering device. Most outboards run plenty rich (cool), but there are gaps and variances with cylinder temperature from idle to WOT as a result of the carburetor. If you've ever installed an EGT gauge on a carbureted 2-stroke, you know what I mean.<br /><br />Even in 1957 outboards were designed to run WOT for extended periods, and they can be loud. Running without intake silencers can cause a lean condition and cause engine damage. If the silencer is removed, jet up. <br /><br />