Overpropped

[Robs]

My 1986 Hatteras sedan with 454 crusaders Gas engines. Best I can get is 3000 rpmsAnd 13.5 kts..Motors runs smooth,start good etc..I’ve change all filters, check carbs,Compression good..Have trim tabs, boat will “almost” planeOff. What size prop should I have for this boat ?Right now I have 26x23.

[Pascal]

Isnthe bottom clean especially the running gear? Was it ok before? How long have own it

[Robs]

Yes bottom cleaned , I’ve owned it for 1 year

[dsharp]

Has that how it’s always run?. Those engines should be turning 4200-4400 rpm at wide open. Can’t really say about the wheel size without knowing the weight of the boat and the gear ratio of the reduction gears. It doesn’t take very many barnacles on the wheels to kill the ability to turn the rated rpm’s. If you’re positive the bottom and wheels are clean then you are severely over propped.

[Robs]

Yes, it’s always ran this way since I bought1 year ago, my local marina called Sams MarineAnd they said we had the right props, my guySaid we’d take them off send to shop and haveCut down to gain rpms ! Does this sound correct ?I figured I need to aleast get boat to plane offAs of now when I’m wot, it feels like I’m justPushing water. Weight of boat is 26,000 lbs

[steve c]

I would have the prop shop check them before cutting them, also what are the no=load WOT RPM's ?

[kelpy]

I would have the prop shop check them before cutting them, also what are the no=load WOT RPM's ?

The no load rpm at WOT will be when the engine experiences terminal valve float. For stock 454s, that should be around 6000-6500 but only for a very short while!!!

[Avenger]

A $50 question looking for a million dollar answer.

Trim tabs working? Fuel filters clean? Check fuel pressure, make sure throttles are actually opening all the way, take the anvil collection out of the boat....

There are dozens of things to look at before you start hacking up the props. Way too much to list here.

[Fish Tales]

My local prop shop has loaned me props many times before. 3 blade sets, 4 blade sets, even loaned me props while mine were being fixed from hitting bottom.

Call your local guy and see if he can assist before altering yours.

Tim

[Boatsb]

A $50 question looking for a million dollar answer.

Trim tabs working? Fuel filters clean? Check fuel pressure, make sure throttles are actually opening all the way, take the anvil collection out of the boat....

There are dozens of things to look at before you start hacking up the props. Way too much to list here.

Can you list them all please?


Fuel issues can be as simple as a carburetor or collapsed fuel line. How did you check them? Is the second stage opening? Id not suspect a failure but maybe someone disabled them. Usually a failure is not in both engines though. if both seem to have the same issue there's another pile of options to look t.

Id first confirm the engines are right before cutting props.