top speed for '97 islander 454 (330hp)
 

i bought a 1997 272 islander last year and absolutely love the boat itself. lots of room to entertain friends and fam. but [B]ROYALLY DISAPPOINTED with my top speed, which is 51.1 (GPS) (down hill with a tailwind) @ 4200 rpm with the stock 19p three blade prop.
Does this sound right to you?
Any suggestions?
Didn't think baja mad a boat that only ran 51.

RPMs sound a little low to me. You should be able to turn closer to 4600 with that motor without issues.

Are you totally sure of the condition of your prop? When was the last time it had a general "tune up" sounds almost as if you aren't firing on all cylinders with those RPM numbers.

Baja certainly has made boats that only run 51.

prop looks okay. going to have it "tuned up" this spring, but i don't think that it really needs it. it isn't bent or dinged up or anything that is noticeable to the eye. was just going to do it a friend suggested it.

My motorman did a mild 502 for a guy in Plano, TX with the same boat. I'm thinking it ran almost 70 when he was done with it.
I really didn't pay much attention at the time, but I'll ask Ben about it & get back to you.

thanx that would be great, because that is exactly what i was wanting to do over the summer

How much does that 27 weigh?

Somthing does sound a little off though. How much trim did you use? Mine only runs in the low 50's when trimmed down all the way. But then trimmed up im into the low 60's.

i have no idea how much it weighs. don't even know how to find out. i trimmed it out as far as it would go, before it started cavitating or slipping.
i also found out that my carb has some internal screens that can get clogged up with bad gas and crud. so i am having the carb rebuilt this week to see if that helps.
sounds like your is running good tho. i would love to b in the lower 60's. is yours a cuddy or islander and do you have the mag?

I am thinking the 275 with the 6.2 320hp small block was running 53 to 55 mph with a 1.5 drive and a 19" prop. The 275 hull is the same as yours but you have more weight forward and a heavier engine. RPMs are definitely low. Should be spinning more than 4200 for sure. Sounds like it needs a tune up. How many hours are on it?

it only has 81 hrs on it. so it has sat alot of its life. any more suggestions?

Fuel, ignition and prop is where I guess I would start. Clean the carb (as you stated) and change the fuel filter. As far as the ignition, you can disconnect the plugs one at a time and make sure each one "changes" how the motor idles. If it does not change the idle, then you know you have a dead cylinder. The prop is stainless correct? It should be a Mirage plus SS 3 blade. SS is worth a couple mph over an aluminum prop.