What is optimum throttle setting for '67 60HP Evinrude V4

[Tinkerer]

This is a thirsty beast.<br /><br />Assuming I want to go anywhere reasonably fast, I figure the best compromise on speed and fuel consumption is to get it up on the plane and keep just enough throttle on to keep it on the plane.<br /><br />I guess that the nearer I get to WOT the less efficient it gets and more fuel it consumes for less result.<br /><br />Anyone know?

 

[Laddies]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

Tinkerer, I hate to tell you but, that would be THIRSTY---Bob

 

[rodbolt]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

having water skied with one of them beasts I think the average was 6 gallons an hour at idle and carry 3 tanks at all times man what a fuel hungry beast.

 

[WillyBWright]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

Give it full throttle until you're out of the hole, then back-off to about 7/8 throttle. You'll hear the motor get quieter, and you'll lose about 3mph over top speed. But that's about where they run their most efficient. Below 3/4 throttle they lose efficiency. The more solidly the boat is on plane, the less the motor has to work. Look at your wake. Big waves mean a lot of wasted energy. 6 gal/hr is about what I got. That's 10 min/gal.

 

[Tinkerer]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

Thanks all.<br /><br />6 gal an hour is about right. <br /><br />Of course, only about half that is actually combusted.

 

[tabbott]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

Where does the other half go?

 

[Tinkerer]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

Originally posted by tabbott:<br /> Where does the other half go?

Straight out the exhaust. I was joking about the quantity, but these ain't the most efficient internal combustion machine ever made.

 

[marinemech]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

tinkerer is correct up to 1/2 fuel goes out of exhaust<br />if you want to play with high speed jets you can lean out motor. i did this to a 1965 75 h.p. it worked' fuel mileage went way up<br />find out what jets are in carbs then reduce size by .010 try motor and increase size until you get a reasonable running motor.note:you may have to use choke to get boat on plane.<br />you also run the risk of burning a piston.its up to you

 

[Tinkerer]

Re: What is optimum throttle setting for '67 60HP Evinrude V4

marinemech<br /><br />You're tempting me.<br /><br />Given the amount of wasted fuel I think there's a bit of leeway before I'd burn a piston. Or maybe they need to be swimming in fuel to avoid holing one.<br /><br />If I had the knowledge I suspect that the trick might be to work out how to change the petrol / oil ratio as the jets change to keep it on the right side of lean. <br /><br />I'm thinking that a fluid of a given viscosity will reach a point where it goes through a smaller hole slower than a bigger one, so when that point is reached the viscosity has to be adjusted to allow the right flow rate. So maybe a 50:1 goes to a 60:1 to allow enough fuel to pass. If it's left at 50:1 less fuel will go through and the leaning effect of the smaller jet will be greater than just the effect of the smaller jet.<br /><br />I'm not explaining this well because I don't know enough to be clear, but maybe you can get my drift.