115 hp prop

[gregtobin]

I have a '74 Merc 1150 on a 17.5' fiberglass boat. Acceleration/hole shot is more important than top end speed. I recently replaced the non-working tach with a new one. I ended up running a new wire from the upper set of connectors (connects to an original green wire) as this is the only post that appears to give me any reading on the tach. WOT gives me about 33 mph (seems slow compared to other forum posts, but who knows how accurate the speedo is) at 4400 rpm. My Mercury repair manual states that WOT should put out 5000 - 5500 rpm. My prop is a three-blade 17p aluminum.

Can I collect some suggestions for improving the hole shot?

Since it seems from reading other posts that the 1150 should be able to spin this prop faster, does this suggest that my motor isn't putting out as much power as it should for a 1974 115 hp Merc? I have replaced the plugs and the carbs do appear wide open at full throttle. Perhaps it is just old with a lot of hours?

Thanks
Greg

 

[gregtobin]

Re: 115 hp prop

I should also have said that the boat is not water-logged. After 2 hours in the water, nothing comes out after pulling the plug. This wasn't the case when I first bought it last year, but I patched some small holes and then coated the bottom with slick laquer paint. I have not yet weighted the boat, but it doesn't ride low in the water and it does appear fairly nimble.