A kick in the back

This topic has 9 replies, 6 voices, and was last updated 18 years ago by oldtimer57.

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May 20, 2008 at 11:36 am #457247

catman2
Participant

I would like to find out if anyone else has experienced this. Boat is a “95 panteraII 150efi. While cruising at 50-55 on smooth surface going straight, every so often the boat jumps slightly in the back. The only way I can describe it is like someone kicked the side of the boat in the back. Its not a hard jolt but it is noticeable. Seems to happen every 30 to 40 seconds. Seems to have a rythem to it. There seems to be no change in rpm or speed. This weekend was the first i ever noticed it. Any ideas?

May 20, 2008 at 12:12 pm #457248

topwater
Participant

More than likely this will keep up till something finally gives out and you find it but my guesses would be something electrical breaking down on the engine like a coil pack or switch box dropping a cyl or two for a second. you might also want to check your prop nut for tightness and the prop hub insert to be sure it not slipping or jerking but these are only guess.. I think its happening so fast right now that you are not noticing any change in RPM or Speed but it there.

May 20, 2008 at 12:23 pm #457249

Bass Cat Boats
Keymaster

Check your messages…

May 20, 2008 at 8:31 pm #457250

Bass Cat Boats
Keymaster

Either the propeller has lost some bite, or the engine is too low, or too high. Either could cause this based on the propeller.

May 20, 2008 at 8:43 pm #457251

oldtimer57
Participant

Heres what I would bet is happening… As you run up or down a river, you pass over lots of submerged hazards (humps, walls, big rocks, trestles, trees, etc. When the current is moving, it produces enormous pockets of underwater turbulence that you can see if you look carefully. When you run thru those, they can interact with the gearcase/skeg/prop and even the boat bottom to produce that “disturbing motion” you are describing. You wont see this on a true lake, or on a reservoir where the current is not flowing. But with all the water of late, most rivers are moving right along and this is a common issue… More noticable the faster the current flows and the shallower the water. You probably will never see this in 300 of water, but in 10-20, it is noticable.2008 Pantera Classic2014 Mercury Pro XS 200

May 21, 2008 at 12:36 am #457252

basscat brett
Participant

Id check to make sure that your engine to jackplate and jackplate to boat bolts are good and tight while you are checking things. I had a similar experience when I first bought my boat (used). At or aorund 60mph the rear of the boat would step out hard sometimes and I never could figure out why – I figured my setup was no good. One day while messing around the back of the boat I checked the bolts that held the hyd jackplate to the boat and they were very, very loose. Since I tightened everything up the “step out” has never re-appeared. I am only guessing they were related but its worth a check.

May 21, 2008 at 11:27 am #457253

Bass Cat Boats
Keymaster

Ill check all the bolts and steering play this week and see if I can find anything. Could motor being to low cause it? Currently setting 3.5 below pad running a 23p trophy with some right hand torque.

May 21, 2008 at 1:34 pm #457254

Bass Cat Boats
Keymaster

OT57, Nope, we know what he has, he has a development on an air pocket on the propeller from the engine height porbably being lower. The Pantera Hull is the most common to encounter this, though all can on this style of hull. It is probably not current etties and is more likely the engine height. BCB

May 21, 2008 at 3:57 pm #457255

Gary Hollander
Participant

Years ago, the “boss” walked me thru correcting this on a PII, which was experiencing the same situation. Engine height is key, along with the tightness of steering components and jackplate to transom and engine to transom. Generally speaking, CatMan was getting right-hand wheel torque, and when in “chop” his hull is hooking up good, and when in “calm” hes getting the “kick”. I believe from talking to him, his engine is too low, but will reserve judgement until he tales his measurements. He doesnt have hydraulic steering, either. After he takes some measurements, and checks his stuff out, Im pretty sure he will have it solved. I have dealt with this “kick” on several past rigs, and again, it comes back to proper set-up… Gary Hollander

May 21, 2008 at 4:50 pm #457256

oldtimer57
Participant

You guys certainly know your boats better than anyone. Ive never seen that particular problem, but that doesnt mean much. I have seen the water turbulence cause a hull to seem like it is “hunting for something” as it runs down the river. On Lay, where I fish, this is common after big rains upriver that have the river stained and trash-filled. Never ridden in a PII, so no experience there. But a family members R-type boat, and anothers J-type boat exhibits this problem on fast-moving water regularly… I had suspected that was the problem based on the water flow rate at local rivers here as we have had a _ton_ of rain this spring as compared to last year… Ive not seen it at places like Guntersville, but on the Coosa it is very common to get this “twitching” feeling when up on plane..2008 Pantera Classic2014 Mercury Pro XS 200
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