1990 VIP vision 4.3 OMC cobra hops while planed out on smooth water

[AnthonyY]

Hello, my omc has loose steering, but it always has and just kinda wanders so maybe it isnt related to my issue. But since the first trip out this season, If I run anywhere close to 4k rpm's which is about 32mph it hops like im going over wake, but the water is smooth. I am sure it is not wake because it was doing it last night and I was literally the only one on the lake. I took it out again today and it was a bit more choppy but the hopping was not going with the wake. It is a very consistant hop. The past few years have taught me quite a bit about the engine in the boat, but I am not at all versed in the "water dynamics" of the lower unit. I have inspected the lower unit and everything looks as it always has. I have heard about the anododes (or whatever they are), but couldn't tell you what it looks like. There is also alot of spray coming directly from the back of the boat. I cannot see the wake from the boat for about 10'. Last year, the spray I am seeing now, was not there. It is coming from in between the unit and the housing(or so it looks like from sitting in very back while underway). I inspected the bellows and they looked normal. I am planning on removing the lower unit and inspecting further, but Im just not sure if there is anything I should be looking for, besides anything that is obviously not right.
the tilt rams are not leaking and on land I cannot move the rams by lifting and the unit stays up while trailering.
PS, I am very excited that my first boat (engine, at least) has survived a second winterization. I sure hope someone here has some input, cause I'm freaking baffled. Thanks again.

 

[AnthonyY]

Re: 1990 VIP vision 4.3 OMC cobra hops while planed out on smooth water

sorry guys, I thought I put this on the omc forum.

 

[AnthonyY]

1990 VIP Vision 4.3 OMC Cobra hops while planed on smooth water

1990 VIP Vision 4.3 OMC Cobra hops while planed on smooth water

Hello, my omc has loose steering, but it always has and just kinda wanders so maybe it isnt related to my issue. But since the first trip out this season, If I run anywhere close to 4k rpm's which is about 32mph it hops like im going over wake, but the water is smooth. I am sure it is not wake because it was doing it last night and I was literally the only one on the lake. I took it out again today and it was a bit more choppy but the hopping was not going with the wake. It is a very consistant hop. The past few years have taught me quite a bit about the engine in the boat, but I am not at all versed in the "water dynamics" of the lower unit. I have inspected the lower unit and everything looks as it always has. I have heard about the anododes (or whatever they are), but couldn't tell you what it looks like. There is also alot of spray coming directly from the back of the boat. I cannot see the wake from the boat for about 10'. Last year, the spray I am seeing now, was not there. It is coming from in between the unit and the housing(or so it looks like from sitting in very back while underway). I inspected the bellows and they looked normal. I am planning on removing the lower unit and inspecting further, but Im just not sure if there is anything I should be looking for, besides anything that is obviously not right.
the tilt rams are not leaking and on land I cannot move the rams by lifting and the unit stays up while trailering.
PS, I am very excited that my first boat (engine, at least) has survived a second winterization. I sure hope someone here has some input, cause I'm freaking baffled. Thanks again.

 

[HT32BSX115]

4.3 OMC cobra hops

4.3 OMC cobra hops

If I run anywhere close to 4k rpm's which is about 32mph it hops like im going over wake, ......... the hopping was not going with the wake. It is a very consistant hop.

Howdy,


You have the drive trimmed out/up too far for your speed........Just trim it in a little at a time until the "hopping" (porpoising) stops. Experiment with different (drive) trim settings.

If it wanders at slow (no-wake) speed, it's normal.


Cheers,


Rick

 

[HT32BSX115]

Re: 1990 VIP Vision 4.3 OMC Cobra hops while planed on smooth water

Re: 1990 VIP Vision 4.3 OMC Cobra hops while planed on smooth water

I answered this question over on the Merc forum.

 

[a70eliminator]

Re: 1990 VIP Vision 4.3 OMC Cobra hops while planed on smooth water

Re: 1990 VIP Vision 4.3 OMC Cobra hops while planed on smooth water

Let me quess, porpoising = too much trim out, doing it trim full in then you need to shift weight to the bow, then there's always the dreaded waterlogged transom and floatation causing the stern heavy condition.

 

[AnthonyY]

Re: 4.3 OMC cobra hops

Re: 4.3 OMC cobra hops

OK, I have been searching the forum trying to find anything about rough ride, or bouncing, or whatever and found the porpoising word in a thread. I searched porpoising and my thread was right there. How cool!!!!!!!!!! I will try to lower the drive and see how it does. This is my third year with this boat and I have never seen it do this before. I think I did move the drive both ways up and down to extreme trying to stop the bouncing. I really hope I was just doin something different than I have done before. What you are saying makes sense to me, it was acting like the steering rams were moving. The irregular spray was happening with the drive in all positions though. I had someone else drive and I sat back there and watched and it was acting like there is something hanging off of, or stuck to the drive and causing the extra spray. I am positive the spray was not happening last season. I am very, very appreciative of the input. I have something to check out now, at least, which is more than I had before. The only reason I am sure of the spray not being right is because I remember when the ladder was left down it was easily noticable. This is like a really big ladder is down right in front of the drive. I forgot to say that I do have the hydrofoils on and they are tight and look just like always. thanks again

 

[AnthonyY]

Re: 4.3 OMC cobra hops

Re: 4.3 OMC cobra hops

so you think that my transom is waterlogged???? When you said flotation, does that mean that next to the bilge there is foam or styrofoam in there that could be waterlogged, I was inspecting the transom yesterday, however I will take a long screwdriver and feel at the bottom and check for it to be waterlogged. I stored it with a cover and a tarp and had it built up so it shed water. The plug is always out (when on land,,,,,,haha). And I always have the trailer cranked way up so if water does get in,,,,hopefully it will run out. If there is foam in the boat "flotation" do I have to remove the floor to get to it. Or how would you suggest I inspect. Drill a hole first?????? I ask of you guys to explain further because this is my first boat and I have been trying to get it running right for 2 years and not that it is there,,,,,,, new issue. Im guessing that that is the nature of the game huh... thanks again for all the input and advice

 

[AnthonyY]

Re: 4.3 OMC cobra hops

Re: 4.3 OMC cobra hops

So If the flotation is waterlogged, will it ever drain out? I inspected the transom and it was not soft or wet. It was about 90 degrees here today so I opened up everything and took off the doghouse and parked the boat on, almost, a 45 degree angle. I left it there all day and it is still parked there. Is there any hope for it to dry out without removing the floor. Oh yeah, the carpet on both sides in the back is damp. I wasn't sure if it was from water below floor, or because of how it was parked it was shaded back there. I understand how hard it is to diagnose something by just some words typed, but I would greatly appreciate anyones input on this. After thinking about one of the posts, I do think the rear of the boat was sitting a bit lower while anchored. thanks again

 

[a70eliminator]

Re: 1990 VIP vision 4.3 OMC cobra hops while planed out on smooth water

If your transom has any rot in it usually it will show up as brown streaks (stains) running down from the transom shield along with some cracking, water can get through the deck and soak the flotation foam through poorly sealed mounting holes like seat hold downs ect. especially if the boat sits out and uncovered. Your probably fine didn't want to get you all worried, my one boat will porpoise violently when it has full tanks (portable 6 gal) along with the 6hp kicker motor all in the stern, it's an outboard with no power trim. My I/O will porpoise with the trim too far out. The tabs you mentioned, are they adjustable? you may need to take a little angle off them.

 

[AnthonyY]

Re: 1990 VIP vision 4.3 OMC cobra hops while planed out on smooth water

No adjustment, I just have the crappy foils. I guess they are,,,,, I am willing to get the smart tabs if they wouldn't be stuuuupid on a 18' boat. The weather has been 90+ degrees here for a couple days and I uncovered the boat and opened the storage and took the doghouse off and parked it on a 45 degree angle for almost 50 hours. Would this help if there is water in the flotation. Do I need a crazy amount of time like weeks or longer at that angle to get it to drain out? or am I hosed (that is if it is waterlogged) and need to replace it. I checked the transom and it is not soft or wet. I wonder if having it covered all the time could cause the humidity in the boat to accellerate the issue. I travel alot and when I am gone, it is for 2 weeks at a time. If we are out on the boat before leaving. I either need to leave the cover off for weeks or cover it within hours of pulling it out of the water. I have a pickup that I use as my "boat dolley" and I have a hitch that allows the boat to be elevated while covered and always leave the plug out. I think Im gonna take it out today and see if my 50 hour 45 degree parking job made any difference. However Im leaving for another couple weeks tomorrow. So, if I understand correctly, the plywood floor should be sealed, not allowing any water underneath of it. I guess I thought that as long as I had the drain out, it would not retain water. Im learning, thanks for the input.

 

[DBreskin]

Re: 1990 VIP vision 4.3 OMC cobra hops while planed out on smooth water

If your flotation foam is waterlogged it will never dry out, even if you leave it for a year in the sun. It doesn't matter if the trailer/boat is tilted or not. The flotation foam is like a sponge and will hold the water until the boat rots.

You mention having "crappy foils". If you have an aftermarket "whale tail" or similar device bolted to your drive, remove it. You'll likely get better performance.

 

[AnthonyY]

Re: 1990 VIP vision 4.3 OMC cobra hops while planed out on smooth water

I was afraid of that. Bummer. Should I go ahead and drill a hole and check for it to be waterlogged? Of course, in an inconspicuis location. Or how would you suggest I check, maybe there is a trick to know for sure. I already figure that if it is waterlogged, I will replace it, fill up with fuel, and go weigh it. That would tell me in the future if Im holding water,,,don't you think???? If I do replace it, should I go to extraordinary measures to keep the water out of there, maybe plastic and silicone lined, or something. Or how about styrofoam, do they have better stuff that doesnt retain water? Iam just full of questions, Thanks again for all the replies. Is there any other reason anyone can think of for the porpoising besides the flotation??? I don't really want to take off the foil, or put on tabs just yet because this issue was not an issue last year and I really dont want to change anything until I can get it back to how it was last year. I could run it as hard as I wanted and there was no hopping. Thanks again