Boat Runs Slower after Rebuild
06-27-2018 | 07:53 AM
#21
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That ignition is set by warming the engine then shut it down. Ground the purple & white ignition shunt wire. Start the engine back up an set the idle to 775 or less rpm. Set timing to 22 degrees below what you want all-in to be. Readjust idle if needed. Then set your idle mix screws for either highest idle or most vacuum. Depending on if you have a vacuum gauge handy. Then readjust idle to 700, 725 or so. Shut off engine then remove ground from purple/white wire.
When you restart, the ignition will correct and smooth out your idle, and it will adjust timing on the go for you. Your idle and other rpm hunting should go away.
Thunderbolt V ignition can't just be set to an all-in value cause it makes adjustments based on acceleration vs steady speed. It constantly advances til it hears knock then backs up a bit. They call it mean best timing.
When you restart, the ignition will correct and smooth out your idle, and it will adjust timing on the go for you. Your idle and other rpm hunting should go away.
Thunderbolt V ignition can't just be set to an all-in value cause it makes adjustments based on acceleration vs steady speed. It constantly advances til it hears knock then backs up a bit. They call it mean best timing.
07-15-2018 | 08:23 PM
#22
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got a chance to take the boat out again today. The changes i made were setting the timing using the the procedure listed above. Set the base timing to 14*. Set idle screws to max vacuum. The boat ran really well. Gets on plane quickly even when fully loaded with people and gear. definitely idles and accelerates much better as well as runs smoother all around. I gave a few speed runs a shot in the late afternoon with no gear, people, or fuel in the boat. It was too choppy to get a good top speed / rpm number. The best i saw was 60 mph @ somewhere around 4900 rpm but the boat was bouncing and hopping all over the place. air temps were 110* with 20% humidity. I found a prop testing sheet from eliminator in my stack paperwork from when i bought the boat.
It says:
236 eagle 454 mag 365hp
mach 22 - 4800 -62mph - 6 seconds on plane
bravo 1 22p - 5100+ - 62mph - 6 seconds
bravo 1 24p 4800 - 64mph - 7 seconds
so maybe a 24p would be a good if i could make enough power to get it to 5k rpm.
What would it take to pull that? would a carb upgrade alone be enough?
It says:
236 eagle 454 mag 365hp
mach 22 - 4800 -62mph - 6 seconds on plane
bravo 1 22p - 5100+ - 62mph - 6 seconds
bravo 1 24p 4800 - 64mph - 7 seconds
so maybe a 24p would be a good if i could make enough power to get it to 5k rpm.
What would it take to pull that? would a carb upgrade alone be enough?
