Straight-Bottom Top Guns with#6 Drives How many??
#141
Registered

Joined: Jan 2006
Posts: 3,860
Likes: 793
From: St. Pete Beach, FL
#143
Fast forward to 2020, I rebuilt the engine I blew up and rigged both motors for Holley EFI. I got them both up and running on the ground. I sent the drive to Colabellas and had that rebuilt. I installed 2" spacers to lower the drives since the boat is no longer on boxes, I am hoping this helps the porpoise issue as the drives are just simply too high without boxes. I was getting ready to put it all back together and then a divorce hit. 3 and a half years later I am finally back at it trying to put this thing back together and see if I can finally enjoy it a little bit. If it is still an ill mannered hopping machine I am going to give up and part it out, somebody smarter than me can figure it out. But maybe, just maybe it will be worth the work and aggravation this boat has caused me since 2016. Time will tell I guess.
#144
The Rat is still around and I'm finally going to put it back together. In 2018 I tried a set of high rake 5 blade props, they lugged the motors hard and when that happened it put me in a part of my timing map on my Daytona Ignition boxes I never tuned, and there was probably 6 degrees more timing then there should have been. I dropped an exhaust valve on the port engine and destroyed a lot of parts. Pulled the boat out of the water and when I spun the drives by hand I heard a knock in the starboard drive. I'm sure I did that leaving the water when it was hopping, the porpoise is real in this thing.
Fast forward to 2020, I rebuilt the engine I blew up and rigged both motors for Holley EFI. I got them both up and running on the ground. I sent the drive to Colabellas and had that rebuilt. I installed 2" spacers to lower the drives since the boat is no longer on boxes, I am hoping this helps the porpoise issue as the drives are just simply too high without boxes. I was getting ready to put it all back together and then a divorce hit. 3 and a half years later I am finally back at it trying to put this thing back together and see if I can finally enjoy it a little bit. If it is still an ill mannered hopping machine I am going to give up and part it out, somebody smarter than me can figure it out. But maybe, just maybe it will be worth the work and aggravation this boat has caused me since 2016. Time will tell I guess.
Fast forward to 2020, I rebuilt the engine I blew up and rigged both motors for Holley EFI. I got them both up and running on the ground. I sent the drive to Colabellas and had that rebuilt. I installed 2" spacers to lower the drives since the boat is no longer on boxes, I am hoping this helps the porpoise issue as the drives are just simply too high without boxes. I was getting ready to put it all back together and then a divorce hit. 3 and a half years later I am finally back at it trying to put this thing back together and see if I can finally enjoy it a little bit. If it is still an ill mannered hopping machine I am going to give up and part it out, somebody smarter than me can figure it out. But maybe, just maybe it will be worth the work and aggravation this boat has caused me since 2016. Time will tell I guess.
man! That is some story! Glad to hear you’re back at it. I always heard the porpoise problem on the rat was due to the 1,000’s of lbs in stereo equipment in the boat.
our #6 gun doesn’t porpoise too bad. Not any worse than our 3a gun did. Not any worse than our cafe with bravos did either. I’ve been running it with a bit of tabs down always though and drives just under or at neutral. But the boat has enough power to run through a little tab drag to keep it planted. Also, run it at
usually 60-75mph, not hard.
you running your props in or out?
#145
man! That is some story! Glad to hear you’re back at it. I always heard the porpoise problem on the rat was due to the 1,000’s of lbs in stereo equipment in the boat.
our #6 gun doesn’t porpoise too bad. Not any worse than our 3a gun did. Not any worse than our cafe with bravos did either. I’ve been running it with a bit of tabs down always though and drives just under or at neutral. But the boat has enough power to run through a little tab drag to keep it planted. Also, run it at
usually 60-75mph, not hard.
you running your props in or out?
our #6 gun doesn’t porpoise too bad. Not any worse than our 3a gun did. Not any worse than our cafe with bravos did either. I’ve been running it with a bit of tabs down always though and drives just under or at neutral. But the boat has enough power to run through a little tab drag to keep it planted. Also, run it at
usually 60-75mph, not hard.
you running your props in or out?
Also, the props that were on it when I lunched the motor were 5 blade Rolla’s, after I hurt it I sent them to ICDEDPPL and he had them worked. He put them on Carpe Diem when he was still on #5’s and had the same lugging issue, in fact I think he might have hurt a motor with those props on his boat if I remember correctly.
#146
Registered

Joined: Nov 2007
Posts: 4,029
Likes: 510
From: Cleveland, Ohio
Matt - was that originally a #5 boat? Do you have any knowledge of where the drives were set when it had that setup? Height wise?
I have a side x side boat (originally a TRS) - converted over to #5s on 12" boxes. When the drives were set highest with no spacers (even with bottom), and if you trimmed up past neutral and were tying to cruise around 55mph - it would porpoise, a little worse than what I would guess is "standard" on a Top Gun. I tried 5 blade Herring sand they were terrible, couldn't really even plane, and when I got it up after at least a mile, slippage was to the moon. I've tried 0", 1" spacer. 2" spacer, 4 blade, 5 blade, spin in, spin out, etc. Lots of setup f'ing around. I found my best setup is (hoping) Spinning in, 1" below surface, 18" diameter prop 4 blade 30pitch will get me right into 95+ mph with great cruise characteristics. I don't have any fancy raked props or newer CNC tech. Just old Merc stainless 4 blades and run it. These boats will never be fast like newer tech, so I just stopped fooling myself.
I stopped trying to chase the 100mph mark and just enjoy the boat - too much downtime.
I have thought about a #6 conversion, keeping them on boxes, but am fearful of the added weight and then negative results. Your thinking may be correct on a deeper setting. Look at Tank's setup - I think he is w/o boxes? And slightly set lower than bottom of hull?
I have a side x side boat (originally a TRS) - converted over to #5s on 12" boxes. When the drives were set highest with no spacers (even with bottom), and if you trimmed up past neutral and were tying to cruise around 55mph - it would porpoise, a little worse than what I would guess is "standard" on a Top Gun. I tried 5 blade Herring sand they were terrible, couldn't really even plane, and when I got it up after at least a mile, slippage was to the moon. I've tried 0", 1" spacer. 2" spacer, 4 blade, 5 blade, spin in, spin out, etc. Lots of setup f'ing around. I found my best setup is (hoping) Spinning in, 1" below surface, 18" diameter prop 4 blade 30pitch will get me right into 95+ mph with great cruise characteristics. I don't have any fancy raked props or newer CNC tech. Just old Merc stainless 4 blades and run it. These boats will never be fast like newer tech, so I just stopped fooling myself.
I stopped trying to chase the 100mph mark and just enjoy the boat - too much downtime.
I have thought about a #6 conversion, keeping them on boxes, but am fearful of the added weight and then negative results. Your thinking may be correct on a deeper setting. Look at Tank's setup - I think he is w/o boxes? And slightly set lower than bottom of hull?
#147
Matt - was that originally a #5 boat? Do you have any knowledge of where the drives were set when it had that setup? Height wise?
I have a side x side boat (originally a TRS) - converted over to #5s on 12" boxes. When the drives were set highest with no spacers (even with bottom), and if you trimmed up past neutral and were tying to cruise around 55mph - it would porpoise, a little worse than what I would guess is "standard" on a Top Gun. I tried 5 blade Herring sand they were terrible, couldn't really even plane, and when I got it up after at least a mile, slippage was to the moon. I've tried 0", 1" spacer. 2" spacer, 4 blade, 5 blade, spin in, spin out, etc. Lots of setup f'ing around. I found my best setup is (hoping) Spinning in, 1" below surface, 18" diameter prop 4 blade 30pitch will get me right into 95+ mph with great cruise characteristics. I don't have any fancy raked props or newer CNC tech. Just old Merc stainless 4 blades and run it. These boats will never be fast like newer tech, so I just stopped fooling myself.
I stopped trying to chase the 100mph mark and just enjoy the boat - too much downtime.
I have thought about a #6 conversion, keeping them on boxes, but am fearful of the added weight and then negative results. Your thinking may be correct on a deeper setting. Look at Tank's setup - I think he is w/o boxes? And slightly set lower than bottom of hull?
I have a side x side boat (originally a TRS) - converted over to #5s on 12" boxes. When the drives were set highest with no spacers (even with bottom), and if you trimmed up past neutral and were tying to cruise around 55mph - it would porpoise, a little worse than what I would guess is "standard" on a Top Gun. I tried 5 blade Herring sand they were terrible, couldn't really even plane, and when I got it up after at least a mile, slippage was to the moon. I've tried 0", 1" spacer. 2" spacer, 4 blade, 5 blade, spin in, spin out, etc. Lots of setup f'ing around. I found my best setup is (hoping) Spinning in, 1" below surface, 18" diameter prop 4 blade 30pitch will get me right into 95+ mph with great cruise characteristics. I don't have any fancy raked props or newer CNC tech. Just old Merc stainless 4 blades and run it. These boats will never be fast like newer tech, so I just stopped fooling myself.
I stopped trying to chase the 100mph mark and just enjoy the boat - too much downtime.
I have thought about a #6 conversion, keeping them on boxes, but am fearful of the added weight and then negative results. Your thinking may be correct on a deeper setting. Look at Tank's setup - I think he is w/o boxes? And slightly set lower than bottom of hull?
#148
It definitely sounds like the high x is your issue. We ran with the rat for a little while on the 05ish key west poker run. Didn’t notice any porpoise. Ran smooth at 80ish.
our 99 gun is vacuum bagged. Dry 6’s, 1,000 hp power, running 17.50x30 / 15 rake mercury 5 blades turning in. Runs 105+ (I haven’t personally seen that or tried but that’s what I’ve been told by prior owners) I ran it up to 95 last time out and it had a lot left. It’s a factory 6 boat and like frick said I heard the x is conservative because it was built to run in the Pacific Ocean in rough water. I’ve eye balled the shafts and they look like they’re even with the bottom of the hull but I need to actually measure it. It pops up on plane pretty easily and has crazy torque, props turning in takes some time getting used to around the dock for sure.
I think you drop that x it’s gonna be the fix you’re looking for.
photo for property sakes lol

our 99 gun is vacuum bagged. Dry 6’s, 1,000 hp power, running 17.50x30 / 15 rake mercury 5 blades turning in. Runs 105+ (I haven’t personally seen that or tried but that’s what I’ve been told by prior owners) I ran it up to 95 last time out and it had a lot left. It’s a factory 6 boat and like frick said I heard the x is conservative because it was built to run in the Pacific Ocean in rough water. I’ve eye balled the shafts and they look like they’re even with the bottom of the hull but I need to actually measure it. It pops up on plane pretty easily and has crazy torque, props turning in takes some time getting used to around the dock for sure.
I think you drop that x it’s gonna be the fix you’re looking for.
photo for property sakes lol

#150




