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fastek3
12-25-2001, 05:16 AM
I have an 81 233 Ls.With stock 260 merc it has run 48 on g.p.s.It is a super rough water boat in great condition but the need for speed is calling. it has merc 1 outdrive and I have been told that it wont last long with the 420 h.p I plan to install.Is there any way to beef up this outdrive if not how long do you think it will last. what m.p.h gain should I see from this I am currently spinning 19p 3 blade Ratio is 1:50

Tinkerboater
12-25-2001, 09:09 PM
I had over 500 hp in front of a #1 merc. drive it finaly said uncle. What helps keep the drive togeather is not shifting with the engine running. Also you will get a lot of looks starting in gear like the V drive boats. Just be very careful----. One other thing don't get the drive out of the water under power.

mercmancolo
12-29-2001, 01:59 AM
If your eng is idleing low enough ,under 850-900 out of gear, then you shouldn't have to start in gear. Idle in gear should be 700-800rpm. The o.d. should handle the shift into gear ok. The problem is accl. You can't hammer it once it's in gear, you have to ease on the throttle till your on plane, then power on up to full power. You also need to make sure the lower unit is a MR. It will have a big nut under the water pump base. This is a more hd lower. You will need to change your prop pitch to a higher number like a 21 or 23. Make it stainless steel not alum. If you blow up the drive you can always change the gimbel houseing and drive to a Brovo 1. Could be expensive but the Bravo 1 will handle the extra hp a lot better.

Tinkerboater
12-29-2001, 03:18 PM
With the bravo drive you will lose speed due to the bigger bullet and added weight. I blew up a #1 drive just idling. My drive was set up stock and it had too much play in the gears. With the engine idling the gears were going back and forth.(lash wasn't tight enough) This broke off a tooth on the upper gear that took out the top housing. And an engine that has to idle at 850 to 900 rpm is going to cam to much. And from my experence with very hot small blocks infront of alpha drives (15 yrs) I don't recomend shifting with the engine running. I was running an 18' boat with an alpha SS with over 500 hp SB FORD running low 90's.