im looking for some more advice i have a 300zx with a 300 yamaha hpdi motor on it and it struggles to get in the low seventy mph range . should it not be alot faster than this? is there any mods i can do to get it faster that wont cost me an arm and a leg ? like a prop or something? any suggestions would be greatly appreciated thanks ,steve
Do you know your prop to pad measurement, prop type & pitch, current rpm's at wot, water pressure at wot, and current gps speed at wot?
If you could post that stuff, several guys can help get you going in the right direction.
its at airport marine being serviced and has some warr. issues thought that a tune up might help it. but ill post the info as soon as pick it up and figure it out. does that speed sound right to you for such a large motor? it basically a 22 ft boat. thanks for the reply. stevej
I don't think you will have trouble getting that boat into the mid-70's with the right set-up, especially in the cooler times of the year. I think it probably just needs a little fine tuning, and possibly a little prop work.
I have a 05 ZX-300 mine runs mid to high 70's. any questions let me know???
Ok, I will bite. I have the same problem with my zx 250 with a 300 yamaha. I am running the 27 pitch yamaha prop and turning 5400 -5500 rpms and running 70-72 mph. The motor allegedly can only turn 5600 rpms (2005), but I heard the 2006 and ups are allowed 5800 rpms. Any thoughts?
I've got a 300 on my 21i. Turn the motor to 6000 rpm, it likes it...
81+ mph..
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rscustomrodsAZ »</TD></TR><TR><TD CLASS="quote">Ok, I will bite. I have the same problem with my zx 250 with a 300 yamaha. I am running the 27 pitch yamaha prop and turning 5400 -5500 rpms and running 70-72 mph. The motor allegedly can only turn 5600 rpms (2005), but I heard the 2006 and ups are allowed 5800 rpms. Any thoughts?
</TD></TR></TABLE>sounds like you need to raise your motor. it will turn 6000 with no problems
"Don't be afraid to see what you see."
Ronald Reagan
Raise it dude! I used to get 81+ also with mine but had sluggish holeshot. Raised engine about 1-1/2" I lost about 1 mph, water pressure is still around 25psi. But this badboy hole shots like the space shuttle now! I thought about tinkering some more with it but considering the large loads I carry(2-240+men plus gear) 78-79gps is good enough for me! by the way I do get 6k rpm's.
Goodluck!
thanks alot guys. I will raise it up. Is everyone running the 27 pitch prop?
10-4 on the 27! I think theres a gentleman here on the boards with an I-class that had his worked by Mark and picked up a few mph. I am fixing to send mine in the next week or two and see what happens.
I think that was me with the 21i.
Sent the stock 27 T down to Mark, boat performed better from launch to top end. Gained about 3 mph. Definately worth having the prop worked...
I run a 25 stock yami prop on my ZX. I don't weigh but 190 and usually don't fish with to many people heavier than that. I always run with full tanks of gas and the boat is loaded with gear. I have had my boat hit 74.4 GPS (by myself) water temp was 80 degrees. Do you guys think i can get much more out of it?
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