71.1 gps in starflite with 225 a 25p quiksilver 5400rpm

[aaronmt]

Went out tonight with the the added 2" spacer for a total setback of 12". This motor is a 1987 yamaha excel i think i could probably use the rpm higher so i may raise the motor 1 hole to see if that gets it up higher. Any ideas what on how to increase the water pressure on this motor. Ive heard but not sure if you can plug the top holes on the lower unit and enlarge the bottom ones any ideas on that? I believe im getting close to the limits of this package any suggestions or ideas? I think the motor feels like it needs to rev a little higher maybe 5600-5800.

 

[illMATTic]

congrats on the speed.:cheers

have you tried any other props? the rpms do seem a bit low. what about a laserII?

 

[aaronmt]

Thanks ILLMATIC the prop that is on it is a 25p quiksiilver lightspeed which is a laserII minus the engraving i got it from boatman. I did try a 23 speedzone but it had to much diameter at 14 3/4 and was a dog out of the hole im going to check the motor height and most likely take it up a hole. At wide open throttle i have 13-14psi so i belive i have a lil more room to work there. Definatley think its getting dialed in better it feels safe at 70 now. Aaron

 

[Adam L.]

Congats on breaking 70!!! Lets see some action shots of the boat.

 

[supergenius74]

71 I'm jealous! Was this with just you in it? how much gas? I still haven't hit 70 yet but I haven't taken it out by myself either. I also am afraid of over loading my engine, I'm at 6800 rpms with a 22p and my bridgeport is known for being designed for high RPMs. I also like my takeoff, I had 8 people in my boat on memorial weekend and it still planed off nice. -shane

 

[aaronmt]

That was with me in the boat and a full tank, its running 70.5 with 2 peolpe and a full tank.I will be raiseing the motor in a hour and taking it out agin be fore work, i think theres a lil more left . I really need some ideas on the water pickup on this. thannks Aaron

 

[F150GT]

I've run my engine pretty high before it starts to drop pressure, you can plug the top opening in the pickup screen and that will give you anouther 1/2". If you really want to go high Yamaha and Merc have the exact same shape lower unit, you can use any merc low water nose cone.

 

[Taube]

i'm running a mazco re 26 on an 79 eluder with 200 2.4 good take off and hitting low 70's at 5800 its hubless

 

[supergenius74]

DId you see any improvement from lifting it? I am thinking of doing the same. I did a bunch of speed runs this weekend and tried to pay very close attention to my RPM's and here is what I noticed. With the 22p chopper I can hit 66 @ 6500 RPM with 2 people and a full tank and just enough trim to help lift the nose but still maintain control. To get in the 68 range I need to trim up so high that it becomes very difficult to steer and my RPM's hit about 6800-7000. I am thinking I need to bring my prop a little higher up in order to get it to the high RPM/HP area so I am thinking about moving it 1 more notch up on the engine mount, I have a CLE with 4-hole low water pickup and good water pressure now so I am not worried yet. Everything I have read says that chopper props work better the higher they are so I hope this does it. -shane

 

[aaronmt]

Im not sure bout the chopper props, i do think if i could go even higher i would. I am cahnging now from bobs 2 inch spacer to a cmc 2 1/2 and adding there 1/2 tansom wedge in hopes that as i countinue to go back i dont lose the height(atleast thats the theory) i wish there was another prob between what i have and a tempest i could use a little better bow lifting prop. But i hope to soon have a lil more power out of my yammi im hope to get it from the 240 its at now to maybe 255. I guess what id say is if u still have good water pressure keep going up , i honestly think these boats would be best at 14" set back where are you at now and what do u have ?These boats need lift more then anything. Best ive seen is 74.7 gps i think with another prop and more out of my motor higher 75-77 isnt out of the question, what elevation u at? Aaron

 

[supergenius74]

I'm at 13.25" of setback and visually the prop shaft is about even with the bottom of the boat. I've tried running it about 3 " lower than this and it wasn't any different, same speed, same takeoff, same water pressure. I am just afraid of over working this engine with a higher pitch prop. I am still not hitting optimum RPM's for this motor, I was told 240 hp @ 6800 RPM for a 2.4 BP EFI. I also was told they are light engines, like 360 lbs. It has a very light cowling compared to by buddy's 2.4 200. If it's light then I probably need more setback but I am not going to stress the transom that much so I will stay where I am at. My speed calculator says I am about where i should be for my weight, it says at 2000 lbs i should hit 71 but at 2200 lbs 69, the difference between 1 or 2 people in the boat. I am hitting 68.5 with 2. I am a bit baffled as to how i could go faster without more HP or less weight. I am pretty much striped to the bone now on weight. Also does anyone know what size fuel tank they have? i thought mine was a 30 gal but it seems to only be about 20. -shane

 

[aaronmt]

The tag on my boat says 29 gals and its a 1987 so i imagine yours is the same. How did you reach 13.25 on set back? My new set up that ill be trying tommorow is a CMC 10" + tthere 2.5" as well as there transom shim between the motor and the 2.5. Ive put the wedge up side down , in hopes that this keeps the motor high and from loosing the hieght from the set back. Ill post pics soon. Aaron

 

[Blizz]

The farther you go back the higher you have to go to achieve optimum ride. Your rpm's will come with unburying the motor choppers are meant to be surfaced not buried..