how many GPH for a Yamaha 60 F
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Dave LeGear
Contributing Member
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Don't confuse fuel burn rates for what performance you may actually see on your hull with the loading and conditions you may encounter.
Now that the "disclaimer" is out of the way
Did you go and look on the Yamaha Web site? They have posted a lot of performance charts Performance Bulletin Home and you "may" be able to match one posted that might be close enough to your hull configuration in both size and weight with one of their test props which I sometimes find, may not have really been the best choice they could have used for a true speed run but to compare with as a "rough" guide.
Short of that, you will find in most cases is that running in 4000 to 4500 RPM will bring you the greatest distance covered for that GPH of fuel burn. Much faster, you only start burning a ton of more fuel for very little actual speed / MPG increase. Flip side of the coin, running at a slower RPM and the hull is not or not fully up on a plane thus plowing water, also burns more fuel for the actual ground covered.
You have to separate GPH from MPG at different points in those performance chart curves since both may or may not apply at those different stages when placed into the "Real World" running. Case in point, who would logically run around at 2 grand only to plow a ton of water all day long? Either drop it back to 1000 RPM and run real slow in a no wake zone OR punch and get it on a plane then back her off to optimum plane speeds and really cover ground at the most efficient rate.
Then you have to compare hull types in those reports. For example, a 1700 skiff hull has a lot of running "wet" surface area (drag) and as such, is really not on a true plane like more traditional V-hull would be. As such will not return a lot of top speed as if that same engine was hanging on a 170 CC that should "if" loaded and propped correctly as it would then ride up on a plane and when trimmed out is going to run. The other end of the scale when looking at those charts, a Cat Hull is really always on a plane even when at rest, and has very little wet running surface. As such are great for range and stability since the center of gravity is outboard. It is just too bad that Triumph does not make a range single engine cat hulls
Speaking of the "optimum" 4 grand running rate though which is pretty much constant be it either a 2 or 4 stroke engine. My Honda will go from the 3 to 4 Gallon rate when trimmed out, to over 15 GPH when running at WOT but really only give me about about 15 to 18 more knots in speed which just does not cover that much "more" actual ground. Actually less "if" kept at such for long since it will binge drink through that tank of fuel much quicker... And (in my case) is kept below the VTEC RPM operating range which is around 4500 RPM. But Bother you would have thought a Turbo waste-gate had closed from both the sound and the quick speed increase when you do punch it above such And I am quickly reminded of such when I am running her up to boil off all the moisture in the lube oil on the run home. This or trying if I waited too late, to out run a storm after saying "Just one more cast, I know that fish is setting just right over there" then look up all of sudden and see black skies and what looks like the 4 horsemen of the apocalypse in the clouds
So yea, it's "way cool" to run them above that RPM band and speed, but that sucking sound you hear on her on most engines is "dollar$" getting sucked out of your wallet when you do return to the pump for some more of that high octane fire water
Now that the "disclaimer" is out of the way
Did you go and look on the Yamaha Web site? They have posted a lot of performance charts Performance Bulletin Home and you "may" be able to match one posted that might be close enough to your hull configuration in both size and weight with one of their test props which I sometimes find, may not have really been the best choice they could have used for a true speed run but to compare with as a "rough" guide. Short of that, you will find in most cases is that running in 4000 to 4500 RPM will bring you the greatest distance covered for that GPH of fuel burn. Much faster, you only start burning a ton of more fuel for very little actual speed / MPG increase. Flip side of the coin, running at a slower RPM and the hull is not or not fully up on a plane thus plowing water, also burns more fuel for the actual ground covered.
You have to separate GPH from MPG at different points in those performance chart curves since both may or may not apply at those different stages when placed into the "Real World" running. Case in point, who would logically run around at 2 grand only to plow a ton of water all day long? Either drop it back to 1000 RPM and run real slow in a no wake zone OR punch and get it on a plane then back her off to optimum plane speeds and really cover ground at the most efficient rate.
Then you have to compare hull types in those reports. For example, a 1700 skiff hull has a lot of running "wet" surface area (drag) and as such, is really not on a true plane like more traditional V-hull would be. As such will not return a lot of top speed as if that same engine was hanging on a 170 CC that should "if" loaded and propped correctly as it would then ride up on a plane and when trimmed out is going to run. The other end of the scale when looking at those charts, a Cat Hull is really always on a plane even when at rest, and has very little wet running surface. As such are great for range and stability since the center of gravity is outboard. It is just too bad that Triumph does not make a range single engine cat hulls
Speaking of the "optimum" 4 grand running rate though which is pretty much constant be it either a 2 or 4 stroke engine. My Honda will go from the 3 to 4 Gallon rate when trimmed out, to over 15 GPH when running at WOT but really only give me about about 15 to 18 more knots in speed which just does not cover that much "more" actual ground. Actually less "if" kept at such for long since it will binge drink through that tank of fuel much quicker... And (in my case) is kept below the VTEC RPM operating range which is around 4500 RPM. But Bother you would have thought a Turbo waste-gate had closed from both the sound and the quick speed increase when you do punch it above such
And I am quickly reminded of such when I am running her up to boil off all the moisture in the lube oil on the run home. This or trying if I waited too late, to out run a storm after saying "Just one more cast, I know that fish is setting just right over there" then look up all of sudden and see black skies and what looks like the 4 horsemen of the apocalypse in the clouds So yea, it's "way cool" to run them above that RPM band and speed, but that sucking sound you hear on her on most engines is "dollar$" getting sucked out of your wallet when you do return to the pump for some more of that high octane fire water
Shallowminded
Participating Member
- City
- Savannah
Don't know if you looked already from the link Puter supplied but here is a performance bulletin for the 170cc and the yam f60 that I got somewhere.
