Hello all, im new to this sight and would love some input! I recently recieved a gift from my wife that has my head spinning, a 30 ft Donzi ZFC. When I got it the gentalman said it did 74 with more to go.BS! It has twin 225 mercs and he had 27 pitch 15" 4 blade props on it. The firstvtime I ran it I couldnt get it past 1800 rpms. My mechanic and I thought carbs were cloged, waste of money. Long story short (obviously) props were soooooo oversized. So now I'm learning props. A little more info , starbord motor kept overheating. After changing everything in cooling system, twice. My mechanic suggested swapping lowers ( thought this might also be good info when speaking about props) because of prop direction?? So cured my overheating problem but still issues with prop preformance. Heres what ive run, with results. In order
21p 14"3 blade- very difficult to get on plane, cavitates hard. Greatly overrevs past 6k rpms. High 30's mph.
23p 15" 4 blade - couldnt get past 2300 rpm
21p 14" 4 blade - cavitated then ran 6200 rpm, gut got 42 mph
same prop adjusted to 23p. But assuming 133/4 " after bending still about the same.
Now after lower swap so curious if more than one factor at work
22p 14 1/4 3 blade. Ok out of hole, slow throtle to 3k then I can open up. Runs about 51 mph but still hitting 6 to 6200 rpms. Book says 55 to 5800 is optimum.
Boat specs. 2000 Donzi ZFC 30ft. Dry weight 4300lbs. Weight as ive run with fuel and gear around 5300 to 5600 lbs.
Can someone please give me some advice!!!!!!
I'll happily fedex an ice cold 12 pack to the one who cures this headache for me!!!
21p 14"3 blade- very difficult to get on plane, cavitates hard. Greatly overrevs past 6k rpms. High 30's mph.
23p 15" 4 blade - couldnt get past 2300 rpm
21p 14" 4 blade - cavitated then ran 6200 rpm, gut got 42 mph
same prop adjusted to 23p. But assuming 133/4 " after bending still about the same.
Now after lower swap so curious if more than one factor at work
22p 14 1/4 3 blade. Ok out of hole, slow throtle to 3k then I can open up. Runs about 51 mph but still hitting 6 to 6200 rpms. Book says 55 to 5800 is optimum.
Boat specs. 2000 Donzi ZFC 30ft. Dry weight 4300lbs. Weight as ive run with fuel and gear around 5300 to 5600 lbs.
Can someone please give me some advice!!!!!!
I'll happily fedex an ice cold 12 pack to the one who cures this headache for me!!!