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Improved fuel efficiency plan

T

the_last_hour

Member
"My current situation is this

"My current situation is this - boat is a 29 phoenix disp = 10000lbs, twin 5.7 350's holley carbed, bought new as a "powerpack" in 2007. Props are 18" (unknown pitch) WOT is 4400 port 4000 star. Mileage is .6 mpg when fully loaded and .9 when light, I did get 1.0 light with perfect bottom and perfect props once. The hull seems to get out of the water at about 3400 rpms and this seems to be an efficient range. At 3000, It is kind of a dog. My goal is 1.2 mpg consistently. In my observations of this forum I've concluded the following....
Apply "propspeed" coating to my props and shafts"
Reduce my prop pitch to get recommended rpms of 5000 ( thats what the stats call for)
Install "fastrails" from the stern forward.
Switch my Holley carbs for edelbrock 1409's
What do the experts say?"
 
"I'd get the props run thr

"I'd get the props run thru the "propscan" process. Give them what you posted above, answer the rest of their questions, and then pay the bill - it will be one of the better investments for economy and efficiency.

If you have the accomodations, I'd get a boat lift installed and put some teflon on the bottom forgoing the propspeed. If not, they make a teflon bottom paint but you need to run the boat frequently to keep it clean. and don't forget the propspeed. If you use the boat frequently, you can probably pass on thte propspeed.

Since you have the holley's, why not try getting them. holley has a decent set of documents on this in their tech library on the www. the only way to get it right is thru trial and error which means giving up maybe several hours to do the tweaking.

Finally, make sure the running gear is in top shape - good cutlass, proper shaft-strut-hull alignment and engine-shaft alignment. Don't forget teflon or gFO in the stuffing box"
 
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