planing problem need serious help or something

[fat1]

Not sure if this is the right forum so I will post in both I guess. Ok guys, here's the problem I have. I took the boat to the lake this morning (1991 Javelin 373FS, fish n ski 1990 evinrude XP 150HP) to go fishing. I pull out of no wake zone and punch the throttle, it jumps on plane in a few seconds and runs like a scolded dog and does this all day. I get back this afternoon and take it down to the river to fish and couldnt get it to plane for over 2 minutes then when it did nose over it started bouncin and slamming into the water so hard I thought it would break in half. It seems to do this only when there is current on the river or if the lake is extremely choppy (4th of July, sunday afternoon, etc.). In fact, I can idle to a calm area of the lake and it will run fine, what could be causing this problem? I am at a loss, I thought it might be a power issue so I de-carbed the motor, changed fuel filter, fuel line, primer bulb but after taking an experienced (auto) mechanic out to listen to the motor I got a clean bill of health but the problem still exists in the afore mentioned situations, any ideas would be greatly appreciated. Please let me know what you think. Also, I took off the hydrofoil that was installed and dropped the trim pin as low as it would go to remove a porpoising issue that existed whenever you were accelerating or driving between 25MPH all the way through 51-52 MPH. Sorry for the long post and thank again for reading.

 

[springhead]

Re: planing problem need serious help or something

im thinking something electrical is loose, could be wrong tho.
When you say it took u over 2 minutes to get to plane it was choppy then and does the motor seem to have the power and run ok when its choppy.

 

[fireman57]

Re: planing problem need serious help or something

Sounds like the hydrofoil was on there because of this problem. Can you trim the engine as you start bouncing and find a spot that will make it go away? Trim tabs are supposed to help this problem out. John with Smart tabs used to post here frequently and people would call him direct for help. If it is a setup problem dhadley is the man for that. There are a couple others that are pretty good at it but he is the best in my book. He'll see this and let you know.

 

[fat1]

Re: planing problem need serious help or something

springhead - if I plane in smooth water and then encounter choppy water the handling is on par with the amount of chop, make sense?

fireman - No, I cant trim out of it or find a sweet spot, I feel like a bullrider having 8 seconds to try to adjust it before I get thrown out of the boat. In fact, I leave the trim down the whole time just trying to get to a good cruising speed of 40-45. I have actually posted a few questions here and at nauticusinc.com about the correct smart tabs for my boat but have yet to receive an answer so I'll have to wait and see.

I'm racking my brain trying to think of all details that could point to something else, in my heart of hearts I really feel it's a power issue but it only seems to show up in choppy water AND one time I idled to calm water and was able to plane. I am not a mechanic nor am I mechanically inclined (30 minutes to change a fuel filter and line) but another friend asked if the choke could be sticking, saying the bouncing and slamming into the water could be from not accelerating fast enough through the transition to plane? We are going to check it, the previous owner mentioned a problem with the choke not engaging at some point so that gives the choke a "history". Also, the mechanic that was with me did not experience this problem so the clean bill of health is a falsehood at this point because it did again after I dropped him off. God, Im so sorry for the long posts but in a nutshell heres the timeline : Had problem, tried the foil/trim pin, things were ok then problem showed up again (water not choppy very often around here), then did the decarb/filter/line/bulb thing, went out today with dude things were cool, then problem came back this afternoon and now I'm here writing a book. thanks again dudes.

 

[tashasdaddy]

Re: planing problem need serious help or something

fat 1, is the engine speed going up and down, or holding steady, and the boat bouncing. i find this unclear.

 

[fat1]

Re: planing problem need serious help or something

Engine speed is steady, I don't get rpm surges or anything. It feels like the throttle is at 3/4 when this problem happens but never surges to full or drops off any further just stays the same.

 

[Silvertip]

Re: planing problem need serious help or something

It seems to me there are two problems here. Handling as well as power. Difficulty getting on plane points to a power issue since it is normally not a problem. The bouncing you describe is a handling issue. I guess the question I have is has this boat always behaved this way or did both problems appear recently? The fact the boat had a foil on it would say it always had a porpoise issue. Engine height and weight distribution could be factors. Difficulty getting on plane is an engine issue and at this point one can only speculate on causes. The porpoise issue could very likely be eliminated with Nauticus Smart-tabs. I have them and will never have another boat without them. One last thought, is this boat fitted with a jack plate?

 

[fat1]

Re: planing problem need serious help or something

no jack plate. the boat is rather light at 1200lbs dry. plus being a fish n ski the cockpit is pretty far forward versus normal bass boats that I am familiar with. I'm going to inspect the choke tomorrow when I have some help (to push the button) and work on the possible power issue first then when its running good and I know there are no problems there i will inspect the possible handling problem. I know the boat wont handle like a typical bass boat but i wouldnt expect it to be uncontrollable or downright scary as it is when this problem occurs.

Like I said, on smooth water or water with just a few boats' wake it's a rocketship and handles like a porsche but rarely this problem shows up and I am unsure as to the cause(s).

I don't know why the hydrofoil was there but it caused more problems than it solved for sure, porpoising in smooth water between 25-50MPH all the way through the speed curve and trim seemed to have no affect on the boat whatsoever. I'll post any info from the choke testing/inspection, as I understand it any stickiness whatsoever is bad.

 

[fat1]

Re: planing problem need serious help or something

I bought this boat in May 2006, I met the guy last year around september and we hung out and fished and tubed and what not but he was not a fisherman at all so was interested in getting a pure pleasurecraft and I jumped on the oppurtunity to pick up the boat cheap (sortof) I picked it up straight from his storage warehouse and de-winterized it. so I didn't see this problem when we would go out or at all really until around the fourth of july but that's also the time the water gets heavy traffic around here so...I also think I may have two problems but I guess I'll find out.

I dont expect the boat to handle like a dream in extremely choppy water but it shouldnt be acting this way i dont think. When the boat did plain in calm water and I ran into the extremely chopper water the bouncing issue was not present at least not like that, there was some bounce that I attributed to the three feet of wake some boats were leaving. I have the kind of luck that would allow a problem to show up at times that point to something else further delaying repair so i'm open to any ideas or possibilities.

also, the previous owner had eluded to the presence of the porpoise issue in the 25-52MPH range but didnt know the casue, once I aquired the boat I took the foil off and move the trim pin as far as it would go so the PTT could move in further under the boat. He was impressed with the difference it made and all was well until recently. I think I have apower issue not allowing me to plane fast enough or at all cuz like I said when it does nose over it starts bouncing and slamming into the water to the point that I have to back out and try again....with no success ever except the time I went to calm water, but still my luck would allow the problem to leave as I did that further confusing me and the people trying to help

 

[Silvertip]

Re: planing problem need serious help or something

You may want to try playing with the trim some more. The fact you have it trimmed "in" so far may actually be "driving" the nose into the water. Some boats simply porpoise within certain speed ranges and you either trim it out or run through that speed range until things settle down. Perforance boats run a very fine line so trim is critical. It can be scary once you hit that 45+ MPH range. Check the position of the antiventilation plate in relation to the bottom of the boat. That's the plate directly above the prop. It should be even with or an inch or two above the keel. If engine height and trim don't help, Smart-Tabs are relatively inexpensive and as I said, should help. Go to the Nauticus web site and read about them. As for the hole shot problem I think that sounds like an engine problem and is very likely fuel related. If you have someone with you when it won't plane, have the passenger squeeze the prmer bulb a time or two. Another trick is to push the key in momentarily If the engine suddently comes to life you have a fuel delivery problem. Have the carbs and fuel pump ever been rebuilt?

 

[fat1]

Re: planing problem need serious help or something

OK, thank you for the tips. I will try the choke thing to see what the results are. I am unsure if the carbs or fuel pump have been rebuilt and I asked the previous owner the same question and he is unsure as well, I am actually the third owner, he owned it six years and never had it done so... I have checked the primer bulb when I stop and it is still tight so I think thats ok but Ive never checked during the problem. I will check the av plate height tomorrow as well. I have noticed that my motor looks extremely long compared to other boats ive been around in my club so that could be an issue. Just to be clear, the keel is the absolute lowest part of the boat where my drain plug goes in correct? thanks again

 

[Silvertip]

Re: planing problem need serious help or something

If the engine is sitting too low, this could very well account for much of the handling problem. You might want to ensure this is not a 25-inch shaft model as well. Measure from the transom bracket (where it sits on the transom) to the AV plate. Long shaft = 20-inch, Extra long shaft = 25-inch.

 

[fat1]

Re: planing problem need serious help or something

the av plate when trimmed in the lowest possible place doesnt sit level so the front of the av plate is about 1 inch above the keel and the rear of the av plate sits about 1/4-1/2 inch above the keel but no part of the av plate in any position sits even with or bleow the keel.

While looking at the choke today, its electronic so I was unable to see any moving parts to see if anything was sticking, however, on the throttle linkage I didnt find a broken spacer, it was split in two so i replaced and am asking you guys if you thought that would cause the problem I am describing?

 

[Silvertip]

Re: planing problem need serious help or something

Engine height sounds ok but probably could probably be one hole higher as as long as you don't lose water pressure. Did you check to make sure the throttle plates are perfectly horizontal when the throttle lever is wide open? What spacer are you talking about that was broken?

 

[fat1]

Re: planing problem need serious help or something

The plates are horizontal. I will take a picture of the spacer and post it tomorrow as I can try to describe it now but I doubt it works. here we go, the throttle cable connects to a large black plastic looking mechanism that has a rod that connects to all three carbs, the rod is connected to this black mechanism on a half-moon shaped device (sort of half-moon) that rotates as the throttle is moved and as it rotates it moves along a post that has a spacer on it which was broken, maybe a cover would be a better word than a spacer but either way I'll take a picture and see if that helps.