exciter handling problem

[Jon Kansanniva]

Hi, here is my setup. 89 exciter, 1991 175 black max, motor is all
the way down on the transom. 23p Laser II prop, I'm getting 57.6
on the GPS at about 5800 rpm. Overall I am happy with the performace.
It has good holeshot and will plane at 25 with no porpoising. However,
on top speed runs when i'm just getting it up on the pad the rear end
will slide sideways at the rpm's go up, speed goes down and the boat
pulls wicked to the right. What is Happening? It also did the same thing
with a 22p laser II small hub prop that I had on it before. Do I need
another style prop (Tempest or Trophy) or is the motor height wrong?
I'm sure I could squeeze 60 out of it if I could stop this issue.

Thanks Jon

 

[john lamon]

My Eluder (same hull as Exciter but open bow) would do the same when I first got it, what you are feeling is the prop breaking the surface of the water and a small amount of blow out.

A torque tab mounted on the skeg will eliminate the feeling of the back end sliding out and the boat will track straight, I also didn't like the way my boat handled with the laser 2, I found that the trophy plus is WAY better for all around use, the laser 2 was faster on top end but sometimes the boat felt squirrly and unpredictable with that prop. A jack plate would help to, I think ndaniels was getting 67gps out of his exciter with a 175.

Here's a link for the torque tab. I hope this helps.


http://thmarine.com/product.cfm?PRID=40

 

[justincase]

An exciter runs best with a tempest

 

[Jon Kansanniva]

Thanks I found this and it explains it perfectly.

Another downside of raising the lower unit is when the prop is raised with respect to the water surface it tends to "paddlewheel." That is, along with pushing or pulling your boat forward, the prop wants to walk on the water like a paddlewheel. This generates a rightward motion to the transom, which causes the boat to turn left. To compensate the driver must turn the wheel right in order to maintain a straight path. Now we have the undesirable effect of "crabbing" the gearcase when the boat travels in a straight line. This creates drag, just the thing we are trying to avoid. At high speeds it also tends to form a bubble on the "shadow" or port side of the gearcase. As the speed increases this bubble trails back further and further until it reaches the propeller. This causes the propeller to blow out or ventilate. Now the prop suddenly stops generating thrust and lift and the bow drops and the boat slows. This is known as gearcase blowout and is usually very dangerous because if one side of the bow catches the water before the other side (or if the steering wheel is not straight) the hull will "hook" and change ends violently. So how does one avoid this "ugliness"? The simple answer is to apply a torque tab to the skeg. This wedge, applied to the right side of the skeg, tends to apply a leftward force to the gearcase which should compensate for the propeller forcing the gearcase right. Now the gearcase doesn’t crab through the water, no bubble, no blowout, no hook and hopefully no accident. Remember when a hull flies the only thing other than the prop in the water is the skeg so it is the single thing left that gives the operator control of the boat. Like flying an airplane with only one small control surface, to say it is crucial is a vast understatement

This is exactly what my boat is doing!! I will order one tonight.

I will also keep my eye open for 23 pitch tempest plus!!

Thanks again guys

 

[HotNBlack]

I'm running almost the identical setup, except I have a jackplate. I have an Elite 24 stainless and I GPS in the low 70s. It is a bit unstable, but still fun. Almost spilled my beer one day.

 

[ndaniels]

John is right.. I was running a 66.6gps fairly easily with a 175 merc- 23P laser II, 8" jackplate at around 3" or so below the pad with very little setup time on it. I didn't have no feedback steering, so it was a bitch holding onto the wheel at that prop height... just like your boat. I'd guess that you have the dual rack type steering like I did- it isn't a no feedback system, so you gotta hold onto it really well. Torque tab would help that some. Hydraulic steering solved all that when I repowered it... I only ran half a season with the jackplate and 175Merc before going to a bigger motor and better steering.

I never tried other props, but I'd trust Ron when he says the tempest is best.. he was running very well with a 150. Also, I was already planning on repowering when I bought the 8" jackplate, or else I would have gone with more setback (10 or 12"). I think there was some left in it with more setback and that 175.

Good luck with it.

 

[Jon Kansanniva]

Update: I had the boat out of the water to put on the torque tab and also
put in a new set of white gauges. While cleaning the ski locker in the
floor I found a 1" threaded pipe with a wire on it! I said there is no way
someone would put a through hull transducer on the pad of a checkmate!!
Well guess what, I crawl underneath the trailer and there it is! Right in the
middle of the pad is a transducer the size of a brick!! No wonder this
thing handles funny and is relatively slow compared to other exciters
with similar power. Any ideas on what to do now? I'll probably leave
it there until winter and fix it then. How much speed do you think this
is costing me? It is about 3" long 2" wide and about 2" thick with a
v shaped front

Thanks Jon