Merc 8hp Prop Pitch size

[scottatwork]

Anyone out there put a 10.5" pitch prop (factory) on their 8hp Merc?<br /><br />Reason I ask is that I'm looking for a little more top end but the propeller has to be factory by the rules of the racing I'll be doing.....<br /><br />I've got a 9" pitch on it now, but I'm not sure if the 10.5" will bog down my engine or not.<br /><br />The entire boat, engine, and me tog ether will weigh exactly 350 lbs.....(By the rules).....<br /><br />Thanks,

 

[Laddies]

Re: Merc 8hp Prop Pitch size

Scott, you need to ck the RPM with a tach, keep the engine just above recommended RPM

 

[rickdb1boat]

Re: Merc 8hp Prop Pitch size

You will lose 200 RPM's for every inch pitch you go up or thereabouts...

 

[scotttu]

Re: Merc 8hp Prop Pitch size

Don't have a tinytach on it yet, will get that after I get the boat in the water.<br /><br />The boat is 8 feet long, me, the boat, and the engine must weigh 350 lbs....<br /><br />So 200 rpm for the advantage of 2 mph might not be a bad thing.<br /><br />Currently estimating the boat will do between 27 and 28 mph......based on other racers....I built my boat a tad lighter than theirs but for the race I will have to be a minimum of 350 lbs...<br /><br />Bob over at Midwest thinks it'll work. I'm going to have to just buy one and try it...<br /><br />Rumor has it at top speed I should be at 5500 rpms......so that might work. I just won't have a fast takeoff and that's OK, this is about circuit and distance racing.

 

[scottatwork]

Re: Merc 8hp Prop Pitch size

Got word back from one of the racers that they tried this alr eady - the 8hp doesn't have enough power to drive that 10.5" pitch prop.<br /><br />Bummer.<br /><br />Anyone got a mid to late 90's Suzuki DT8 for sale????