2052 Trophy Pro Holeshot issues

[antney1]

I have a 2004 trophy pro 2052 with a 4.3 mercruiser, alpha 1 outdrive, heres my issue… when i get out of the river and throw the hammer down im getting 3600rpm, boat only doing +\- 11mph… eventually the mph creeps up (takes a long long time) then eventually gets in the mid/upper teens and planes out. At that point im at +\- 4k rpm. New plugs, cap & rotor. I had the prop replaced last fall before putting it away for the winter.. discovered the prop was a 14.25, 21 pitch. Beth at Mike’s gave me a 14.25, 18 pitch to try out, got to the lake, hammer down, rpms were over 5k but still not going anywhere… thoughts ??

[mahine111]

I have a same boat, my has 14-1/2 x 19 prop, boat gets up on plane pretty fast,  trim tabs do help a lot…

[thumbburn]

How long has boat been doing this?…. The entire time you have owned it?…

[antney1]

Ive had the boat since ‘12, never was an issue. Last fall was doing the same thing but was told it was algae on the bottom creating a suction, i thought it was because my prop was dinged up

 

 

[antney1]

Thank you Mahine, shes got tabs. I will see if i can find your prop and test it

[sherman brown]

going down only 2" in pitch should not gain a 1000 RPMs. if your motor is already doing 5000 RPMs you don't want to drop pitch any more unless that 5000 is while your taking off. what is your RPKs after you get leveled off? a 19p prop is usually a catch all that dealers use so they still work but won't over tach. the 21 sounds liuke someone was dreaming of getting more speed. but when over pitched it hurts everything.

 

if the 5000 RPMs you mention is when you are taking off check to see if the prop has holes back all the way around it. or if it has plugs in the holes. these control the spin of the prop letting it spin faster if the plugs are removed and slower when the plugs are installed. when you are planed of your RPMs shout not exceed mercruiser recommended RPMs for that motor. and just guessing im thinking about 4800 max when leveled off. but knowing about those plugs or holes will tell me everything.

 

algae and barnacles on the bottom can make a difference but i don't believe that was your only problem. and only if you leave your boat in the water will the build up get real bad. what was your speed and RPMs with the 21p before the problem started?

 

my best advice without knowing more i would switch to a 17p 4 blade like a rev 4, this will greatly improve your hole shot and better handling in turns and rough water. dropping to a 17p will keep your RPMs close to right but you may lose 1 or 2 MPH on top end if you had a 3 blade that was what you needed. but i would guess going to the 4 blade 17p it will give you much better lift and should give you a few more MPH.

 

if the 18p prop has the plugs removed it lets water escape through the holes and makes it easier to turn and raises the RPMs which should give you a little better hole shot but maybe not help much when leveled off. please let us know about the holes and if they are plugged? using smaller plugs will also raise your RPMs on take off so just having plugs in them may not be the ones it needs to lower the RPMs on takeoff.

 

if it was my boat i would just switch to a revolution 4 blade 17p and be done with it. but there are many other good 4 blade props but i recommend the rev 4 in 17p. a 4 blade is harder to turn causing lower RPMs hence dropping to a 17p will cure that.

[antney1]

Plugs and holes ? Not to sound stupid but i have no idea what plugs and holes in a prop are. The 21 pitch prop was doing 3600 at wot and only 11mph until it finally creeped up to plane topping out around 4000. When i tried the temp replacement prop the tach was going crazy between 5000-6000 and not wanting to damage my motor i pulled back and came back. 

[sherman brown]

a lot of newer props have black plugs up front near the leading edge. these plugs can be removed or replaced with smaller plugs. this interrupts the flow of water to llet the prop turn faster on takeoff. if you look at the prop if it has the plugs, you can't miss them.

 

are you sure the hub wasn't bad and slipping? but anyway i believe the 21p is way too high. but the 18p should have improver your hole shot and raised your RPMs about 500 or 600. i have been a little more up on props ever since i started needing to know about pitch.

 

i started with an old 14' boat and 15 hp motor. my bil and his friend had an old house boat with a 50 hp Johnson on it. they had a falling out because the friend didn't want to help with the upkeep so they parted it out and i bought the 50 hp and put on my boat. it took off at almost full speed. but after blowing the reed valves twice i found out they had an 11p power prop on it on the hb. so on my boat without a tach it was over revving a lot and i didn't have a clue. i got rid of the motor.

 

later when i had an 80 hp mariner with a 19p 3 blade that was great on my 16' runabout. but then i went to an old heavy aluminum 18' Cherokee and loaded for Erie it took it forever to get on plane,. then i had a chance to buy an aluminum 15p prop for half price. it was the only prop he had left to fit my motor. i went ahead and bought it for a spare. a few trips later with the 19p i wanted to just try the 15p to make sure it worked for me. when i hit the throttle the boat jumped on plane and was running great. but it was over revving so i backed off on the throttle. but i learned so much about pitch. i thought about getting a 17p thinking it was just what i needed. but i liked the way the 15p was doing so i left it on and just backed off a little on top end.

 

but i still recommend going to a 17p 4 blade of your choice. a 4 blade is just a better all around prop than a 3 blade in my opinion. and don't feel alone in not knowing about the plugs they just started a few years ago. but you can google what are the vent holes in marine props and learn more. i was as dumb as they come about prop pitch when i started boating.

[antney1]

Well a buddy of mine gave me a 4 blade 16 pitch to try out today and what a difference.. in a few seconds up on plane, 4200 wot… manual says 4400-4800 is the range so im pleased. This was with just myself, my gf and 1/4 tank of gas. Out tomorrow with a buddy thatll add another 230+ lbs of beef… well see how she does 

[sherman brown]

21 hours ago, antney1 said:

Well a buddy of mine gave me a 4 blade 16 pitch to try out today and what a difference.. in a few seconds up on plane, 4200 wot… manual says 4400-4800 is the range so im pleased. This was with just myself, my gf and 1/4 tank of gas. Out tomorrow with a buddy thatll add another 230+ lbs of beef… well see how she does 

when i went to my 17p high five it didn't seem to matter at all if i was loaded with 5 of us plus our gear and our food cooler filled full of food soda and ice and our fish cooler with 2 bags of ice. it still jumped on plane and ran faster on Erie than we were able to run with rough water.

 

good luck with the 4 blade it should serve you very well. please do report back on running a load.