I am an idiot...no need to point it out, just help please.

[Viddi]

Re: I am an idiot...no need to point it out, just help please.

I'm not sure if I should start a new thread, but here is another update w/ more info.

I replaced the prop and hub, and now when I try to turn it while in gear it doesn't spin, even with a fair bit of force. The hub was def. spun.

I took her out for a test, and she runs great at low speed (not on plane), but when I try to get on plane, my rev's are lower (+/-2500-3000) and it just seems like I am plowing through the water. occasionally I get a bit of shudder/vibration, but I can't get on plane in even remotely rough water. I was able to tease it up onto plane on smooth water, but still didn't have the hp I should.

I think I have narrowed it down to 2 things

1. the coupler (can someone reccomend a test for this) As I mentioned it doesn't slip when I turn it by hand, but it is obviously not under load. It also doesn't overheat (except when the water hose to the engine came off and pumped the bilger full of water!)
2. cavitation from the exhaust. Considering the damage I have done to the lower by the prop "eating" into it, is it reasonable to conclude that the exhaust is escaping around the base of the prop instead of through the middle? If this is the case, then my prop would mainly be pushing against air instead of water...

Thought, or suggestions?

 

[proxyx]

Re: I am an idiot...no need to point it out, just help please.

bad coupler smells like burnt rubber, when it happens you have a small smoke cloud in the back of the engine, the boat reaches high rpm and doesn't move accordingly, your case is you can't reach the rpm... you sure?
"I was giving her full throttle when all of a sudden the rev's go through the roof" sounds like coupler or a prop. Bt Doctur spoke about that.
Give it full gas for a moment if on the lake, if it revs up past 3000 and boat is like bolted then coupler is very likely. You can't spin a smoked coupler by hand, still strong enough but a bar will do that. It consists of 2 rubber cylinders vulcanized together. If it breaks it's useless, no repair... unless you weld the spline to the flywheel (LOL, not recommended!)
I don't buy cavitation thing... not today.

 

[Viddi]

Re: I am an idiot...no need to point it out, just help please.

Give it full gas for a moment if on the lake, if it revs up past 3000 and boat is like bolted then coupler is very likely. .

What does "like bolted" mean?

Perhaps I should have been more clear. Originally the "rev's went through the roof". I had zero propulsion. I have sinece changed the prop and hub and I now have thrust, but can't ge up on plane.

I don't get a burnt rubber smell now, but a few months back when my gimbal went, I did see some smoke and a burnt rubber smell (along with alot of nasty metal grinding!) I have since replaced the drive w/ and SEI unit, hence asking if the shop would have checked the coupler when they replaced the gimbal after it failed. Is it common for the gimbal and coupler to fail at the same time?

IS it aso common to have a prop hub, and coupler fail at the same time?

Anyone at all think it could be exhaust escaping? I guess I won't know for sure until I test the coupler, or get the SEI lower unit replaced under their 3 yr no fault warranty

 

[bigskiohio]

Re: I am an idiot...no need to point it out, just help please.

a coupler wont let you give it any throttle if it is bad,it will just slip heat up and then smell. it wont get better plus it has nothing to do with low revs,

 

[krisnowicki]

Re: I am an idiot...no need to point it out, just help please.

if your ncoupler is bad you will experiance over heat because the engine willl not turn the drive which turns the water pump. So no turning = over heat. IF you are not over heat your coupler is probably ok esp if you get the rpms up and it does not over heat. When you got a new prop did you get the same pitch and diamater? If the drive is dmaged and you bought a new one SEI's warranty will cover abuse

 

[Viddi]

Re: I am an idiot...no need to point it out, just help please.

if your ncoupler is bad you will experiance over heat because the engine willl not turn the drive which turns the water pump. So no turning = over heat. IF you are not over heat your coupler is probably ok esp if you get the rpms up and it does not over heat. When you got a new prop did you get the same pitch and diamater? If the drive is dmaged and you bought a new one SEI's warranty will cover abuse

Yes, I was thinking (perhaps hoping) that it is not the coupler. I have also read that usually once they go, they go...

When I replaced the prop, it was with the exact same model.

The only thing I can think of is that the exhaust is escaping around the prop. With a new drive and a new prop/hub, what else could it be....aside from a faulty drive?

Crappy thing for me is that not too many ppl here seem to be biting on my exhaust theory, and I am pretty much a noob

I guess I'll have to pull her out and send the lower back to SEI...unless somebody else can shed some light for me.

Thanks for all the help BTW. Not only is it appreciated, but I am feeling much more knowledgeable around my boat.

 

[cooter2506]

Re: I am an idiot...no need to point it out, just help please.

If it was cavitating due to high exhaust output from the drive it would have HIGH rpms. I would call SEI and see if they want the lower back or the whole thing replaced.

 

[Viddi]

Re: I am an idiot...no need to point it out, just help please.

If it was cavitating due to high exhaust output from the drive it would have HIGH rpms. I would call SEI and see if they want the lower back or the whole thing replaced.

Any suggestions as to what it could be then?

I suppose I should clarify w/ respect to the rpm. They will rise when I give more throttle, but I just can't get up on plane. The one time I was able to get on plane, I think the rpm were in about the right range, it just seems like I didn't have as much hp as I should.

That is why I figured that it may be the exhaust...once I get enough grip on the water to overcome the pressure of the exhaust it will close the gap and run closer to "normal", but as I try to get on plane it is a battle b/w the the prop pushing against the water, and the exhaust pushing against the prop...Not sure if that made sense???

I'm going down to the cabin later today. I will try to test it again so I can be a little more specific as to exactly what it is doing in certain circumstances.