High throttle, no go. Low throttle, go. ???

[shioner2001]

So, that title should pretty much sum it up. Any ideas? Kidding of course. Here we go. 87 Four Winns Horizon 170, Merc 165, Alpha One. Just installed a new prop yesterday (21p aluminum) and when I took it out to the lake today and tried to get on the throttle, the engine revved, but there was no drive. At low speeds getting out of the no wake, the boat was fine. It also shifted into reverse just fine. But, like I said, when going from low throttle and slow cruising to a higher throttle or hammer down, it just revs and stops transferring power to the prop.

So, I took it home and this is what info I have for you. When I put it in forward gear, the prop will not spin by hand in the reverse direction, but "clicks" and spins relatively freely in the forward direction. Vice versa when I put it in reverse. It spins relatively freely in reverse with the "clicks", but will not spin at all forward. The clicking sound is coming from the lower unit. The only variable from when it ran great to this situation was the prop change. I've searched around, but didn't see this exact scenario, or at least described such as this. Any thoughts or ideas?

 

[bomar76]

Re: High throttle, no go. Low throttle, go. ???

The clicking is irrelevent, that's what it does.
Your new prop has a bad hub.

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

I pulled the prop and hub and it looks to me like there is no way for any slippage there. Everything fits together perfectly and there are no marks where anything could have slipped. I originally thought (hoped) that it was the prop as well, but it just doesn't seem like that is possible from the way it all looks and is still made up.

???

 

[bomar76]

Re: High throttle, no go. Low throttle, go. ???

Agian....t's the hub.
There is no way you can just look at a hub and judge it is good or bad.
Put a line on the hub and prop w/ a marker or nail polish, reinstall, launch the boat, recover boat, remove prop, look at how the marks have moved.
Or just ahve the hub fixed and avoid all that work for nothing.
There is no way you can just look at a hub and judge it is good or bad.

 

[ziggy]

Re: High throttle, no go. Low throttle, go. ???

Your new prop has a bad hub.

that's what i'd think too. specially since ya apperently didn't have issue prior to the prop change.... if ya wanna see. paint a line on it accross the hub and the prop. take her for a run then look at the lines. if their still together, it's not the hub and ya'll have to investigate further. but if they ain't lined up. the hub it is.....

 

[thumpar]

Re: High throttle, no go. Low throttle, go. ???

If you have the old prop put it on and try it.

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

Forgive me for not understanding exactly, but if the hub was bad, wouldn't I be able to see wear (tooling) marks where there was slippage? I just pulled it apart again and it doesn't look like there was ANY movement between any two mated surfaces, nor does it look possible for there TO be. For what it's worth, and for me to clarify for my own edification, this a a Quicksilver prop with a Flo Torq 2 Hub Assembly Kit. I am assuming that what Quicksilver refers to as the "drive sleeve" is what we are ferring to as the hub, correct? This is the octagonally shaped hard plastic sleeve that slides inside the prop. Then the prop and the "Drive Sleeve Adapter."

Sorry, just a little confused.

 

[bomar76]

Re: High throttle, no go. Low throttle, go. ???

OK, if you don't believe us, do this:
Pull engine and replace coupler.
Have outdrive totally rebuilt too.
Reinstall all.
Put the "New" prop back on.
It will still exhibit the same symptoms...

CAUSE THE PROP HUB IS SLIPPING.

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

Hey Bomar, CHILL. I am asking questions so that I can LEARN, not calling you a liar.

 

[bomar76]

Re: High throttle, no go. Low throttle, go. ???

I am done with this one....

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

Fair enough. Don't call me bud then. Now back to the task at hand.

Now, for everyone else. What I am trying to understand is exactly what two surfaces are supposedly slipping against each other. Is it the plastic (not rubber) sleeve that mates with the inside of the prop or is it the metal (brass?) drive sleeve adapter that fits inside the drive sleeve (these being the two pieces that sandwich the prop)? And also what I don't get is that, as fast as the enine was revving (wot for a bit), how can there be zero visible evidence of slippage? It is that lack of marking between any two of the surfaces that led me to believe it may be internal.

Attached is picture of the hub that I just took. If that matters at all, figured it couldn't hurt. It appears to be made of a very high density plastic, very unforgiving and not something that would deform before cracking.

 

[JustJason]

Re: High throttle, no go. Low throttle, go. ???

if you pop the hatch does it smell like burning rubber?????
Is there metally rubbery gooey goodness in the back of the bilge area???

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

if you pop the hatch does it smell like burning rubber?????
Is there metally rubbery gooey goodness in the back of the bilge area???

Negative on both accounts. Which I will assume is a good thing...

 

[muc]

Re: High throttle, no go. Low throttle, go. ???

sounds like you might have the wrong thrust hub (the big washer) in front of the prop. That could allow exhaust gases to get out between the prop and gear housing. Note; if the hub that you have slips --- you WILL be able to see the damage.

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

sounds like you might have the wrong thrust hub (the big washer) in front of the prop. That could allow exhaust gases to get out between the prop and gear housing. Note; if the hub that you have slips --- you WILL be able to see the damage.

I will pull it off again and compare with the washer that I removed. If they are indeed different, I will try the old one. (There's nothing wrong with reusing that part is there?)

And as far as being able to see the damage, that makes a ton more sense. After running it like this (with the problem today) and taking it all apart, there was absolutely no difference than when it came out of the box. Which made me wonder what replacing it with an identical part would do.

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

I will pull it off again and compare with the washer that I removed. If they are indeed different, I will try the old one. (There's nothing wrong with reusing that part is there?)

And as far as being able to see the damage, that makes a ton more sense. After running it like this (with the problem today) and taking it all apart, there was absolutely no difference than when it came out of the box. Which made me wonder what replacing it with an identical part would do.

On another note, what does the exhaust getting out there have to do with the problem I am having? How does all of that tie together and what are all of the thrust washer's jobs?

 

[shioner2001]

Re: High throttle, no go. Low throttle, go. ???

Ok, pulled it apart one more time and the thrust washer was indeed different that the one that was originally on there (different shoulder relief and OD as well). Also, the OD of the cylindrical part of the prop (I'm sure there's a name for it, but I don't know what it is) was different from the original prop, thus leaving a larger radial gap between the prop and the lower unit. So, back to West Marine tomorrow to give them an earful and hopefully return home with the right parts (as these were "definitely the parts you need, sir" when I went in to get them the other day).

Thanks for everyone's help, especially those that chose to pay attention to what I was saying and offer assistance based on what was happening as opposed to sticking with the conclusion that they prematurely jumped to. Much help.

 

[JustJason]

Re: High throttle, no go. Low throttle, go. ???

well.....
if your prop hub ain't spun....
and your coupler ain't spun.....
it really only leaves ventilation.....
and if you have a different trust washer... thats probably your probelm

 

[Bondo]

Re: High throttle, no go. Low throttle, go. ???

Ok, pulled it apart one more time and the thrust washer was indeed different that the one that was originally on there (different shoulder relief and OD as well). Also, the OD of the cylindrical part of the prop (I'm sure there's a name for it, but I don't know what it is) was different from the original prop, thus leaving a larger radial gap between the prop and the lower unit.

Ayuh,...

You installed a prop made for the mid-sized Outboard motor,.... They use a 4" gear case,+ prop body....

I/Os use a 4, 1/2" gear case,+prop body.....

That's Why it ventalating so Bad..... Get the Right Prop....

 

[JustJason]

Re: High throttle, no go. Low throttle, go. ???

bring your old prop (whatever condition its in) and bring the new one to the place you bought them and see if they will get you with right prop