Can u get better fuel "mileage" with a certain pitch prop?

[excalibur-oc]

Re: Can u get better fuel

Re: Can u get better fuel

 

[excalibur-oc]

Re: Can u get better fuel

Re: Can u get better fuel

 

[excalibur-oc]

Re: Can u get better fuel

Re: Can u get better fuel

 

[Texasmark]

Re: Can u get better fuel

Re: Can u get better fuel

Tell you what I see in your pics

Alum prop; Repl with HP SS; Cupping and rake should help.

Engine too low on hull. Anti vent plate below bottom = excessive drag. But when you jack it up to even or above, you will need the HP sS prop to prevent blowout.

Hull is deep V....takes more power than flat bottoms Hp/fuel higher requriement.

Boat is big and looks to be heavy.....more hp/fuel to push

Being an Airslot, the water coming off the center hull, hitting the sponsons creates drag....more hp/fuel nice ride, but you pay the price.

So what can you do?

Jack the engine up and get a SS prop....go to prop forum and d and Ken will talk you through it.

You should get some perf and fuel enhancement, but the rest is there to stay.

HTH,

Mark

 

[excalibur-oc]

Re: Can u get better fuel

Re: Can u get better fuel

Mark,
Just goes to show how little us common folk know.
I always felt my engine was too high. That was from observing & checking out other boats.

I will definetly be trying your suggestions & will be disussing my prop options.

How high should I raise motor? The cavitation plate slightly above boat bottom?

What are you recommending with perf & fuel enhancements.

Ex

 

[studlymandingo]

Re: Can u get better fuel

Re: Can u get better fuel

Try moving the motor up one hole at a time, you want it so you don't blow out the prop when you are underway, you will likely get some surface chop when you are trimmed all of the way out. I notice you have a cross-pin in your motor mount; is there a reason you have it there? It looks like you have power trim and tilt on that motor, so you really shouldn't need the pin. There will be times when you want all of the motor "tuck" you can get when coming out of the hole.

I have a navman fuel flow transducer that I recently hooked up on my boat; I was actually surprised to find that I was most efficient at about 33 MPH.

 

[excalibur-oc]

Re: Can u get better fuel

Re: Can u get better fuel

That was what I planned - 1 hole at a time, as a matter of fact I was thinking I would probably only go up 1 hole.
This would bring the plate just above the bottom of the V.

The cross pin was there when I bought the B&m, I have never moved it.
I will take it off now that you have responded. I figured it was some type of safety feature on the power TnT.

Excuse my ignorance but what is a fuel flow transducer & what exactly does it do.

 

[excalibur-oc]

Re: Can u get better fuel

Re: Can u get better fuel

Before I start with the setup improvements I was considering the installation of a tilt&trim gauge, a freind of mine had one yrs ago on a 93 J. As well as a volt meter.
Can this be done on my '81 175J & if so how difficult would it be. My belief is that it we help me monitor the improvements/changes better.

What do you fellows think.