hey guys i got a 25 foot donzi ragazza i just took the 260 hp motor out and replace it with a 325 hp. the thing is im still using the old 3 blade from the 260 hp motor. it's 14 1/2 x 19. the new engine has a 5000 rpm wot but for some reason im only getting 4000 rpm. can someone tell me what prop would get me to plane faster, my 1000 rpm im losing and a bit more speed on the boat. thanks in advance guys.

What WOT rpm were turning with the 260hp engine?? You should have gained about 400rpms with the additional 65hp.

Something is goofy. You should have gained rpm. I feel 400 rpm is a little lofty but a couple hundred rpm should have come along. The old performance numbers will be helpful.

Brett

it was 4000 with the 260 seem like i got the seem speed with a bigger engine lol.

Same boat, same prop, same numbers but more HP.

Does the new engine weigh more? Has anything else been changed?

just a little more but i just want to know what prop would be good should i keed the 3 blade 14 1/2 x 19? i was told to use a 15x 17 alum or a 15 1/2 x 17 stainless i would really love to get that 400 rpm the boat seem to take long to plane when im carring a load. i would have to take it to about 3000 rpm to get plane but is still sits low to me plz help me out.

i agree with these guy somthing is not rigth check your timing on the motor ????maybe its off .

its a new engine and the timing is fine. i called jasper the ones that made the engine they said it's 4900 to 5000 rpm wot. im not getting pass 4000 is takes me like 3000 rpm to get on plane dont seem right. im thinking i need a less pitch with a bigger prop not sure about thses things.