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Ventilating

Posted: Tue Apr 07, 2015 12:53 pm
by Tank5
New to the site,
Bought a new Xcursion X-23fl with a yamaha f150. My question is for other Xcursion owners how high is the outboard mounted having issues with prop ventilation. From a dead stop the prop hooks up fine, if cruising 8 or 10 mph and open it up the prop never seems to grab. Never had this issue on all the ski boats I have owned.

Re: Ventilating

Posted: Tue Apr 07, 2015 1:55 pm
by GXPWeasel
This shouldn't matter whether the boat is an Xcursion or any other type of pontoon.

The engine should be just low enough so that when underway, the top of the cavitation plate should just be skimming the water. Take a look while you're cruising, and see where yours is. You may need to lower your engine a bolt hole or two, if possible.

If you're already as low as you can go, you might consider a 4 blade prop, or a prop guard. A couple other people on here have had luck doing that to their motors.

As a last resort, you could always see if you maybe don't have the long shaft lower unit, and upgrade to that.

Re: Ventilating

Posted: Tue Apr 07, 2015 2:27 pm
by Tank5
I can drop the motor one more hole. I took the boat back to the dealer for this issue and a couple of other. Trying to gather all the knowledge possible. It seems that there are many pontoons set up just like ours, just hoping someone else had the same issue and had the solution.

Re: Ventilating

Posted: Tue Apr 07, 2015 9:24 pm
by Bamaman
I can only speak for my Bennington and my F150. My engine is set 1 notch above the lowest setting, or about 3/4" up.

My dealer started out with a M14 Yamaha stainless prop, however it was 4 mph slow, and hitting the rev limiter at 6300 rpm's. I returned the prop, and he switched me to the Reliance 15 pitch. Now, I'm running 6000 rpm's at full throttle at 40-41 mph gps.

I run my boat trimmed up about 3/4 of the way up. And when I hit it hard from a dead start, I get a little ventilation--just like I like it. When getting up to cruising speed, I'm running at optimum engine height. I seldom even adjust my engine trim.

Are you running a Reliance stainless steel prop? When you get up to speed, trim your engine up and throw the throttle to it, what's your speed and your rpm's?

If you're running the proper rpm's and are getting good speed with your prop, your option would be to drop the engine a notch. Until your propped right, you don't want to mess with the engine height.

Re: Ventilating

Posted: Tue Apr 07, 2015 10:58 pm
by Littlehoe
I have an xcursion with a yamaha 115 and mine is set as low as she goes. I am running a 4 blade aluminum prop right now but this spring we will be doing some prop testing for my dealership to see if we can find something better.

Re: Ventilating

Posted: Wed Apr 08, 2015 2:13 am
by Tank5
Bamaman,

The other issue I had this weekend was that the motor would only run WOT for about 20 seconds before it would cut out. I never really was able to run it all out. From a dead stop I was able to get to 31 MPH at about 5100 RPM before the motor cut out.