21 prop on Merc 4.3 hits limiter..help??

[somefun]

Hey all,<br /><br />Need some sdvice please:<br /><br />I have a 2005 Maxum SR3 18 ft. It came with a 14 -23 prop which would only get to 4500 rpm and was slow out of the hole. I changed it this year to an Alum 14 1/4 X 21 Black Max, now its getting to 5000 and hitting the rev limiter.<br /><br />Any suggestions? I thought I should only gain about 200 RPM from this change? How bad is to hit the limiter? Has anyone else with a boat this size experienced this issue when they changed? What did you do? <br /><br />Any help would be great, think I just wasted $300.00 !

 

[Tail_Gunner]

Re: 21 prop on Merc 4.3 hits limiter..help??

Smart Tabs, then vent your 23p prop. Use the search to understand venting a prop. From there post your results and ask walleyehed.

 

[WillyBWright]

Re: 21 prop on Merc 4.3 hits limiter..help??

200 per inch. That's a 2 inch difference. Have you ever considered backing-off the throttle? Full throttle is Not a requirement.

 

[somefun]

Re: 21 prop on Merc 4.3 hits limiter..help??

Thanks Ill read about the tabs and venting. <br /><br />Full throttle is not required, true. Is it harmul if i accidently hit the limiter ever now and again?

 

[WillyBWright]

Re: 21 prop on Merc 4.3 hits limiter..help??

Many boats are intentionally underpropped. Ski boats, commercial fishing boats, utility boats. They underprop for a light load so the motor is best configured for a full load. They simply watch their RPMs and ignore MPH.