1981 Aquasport 170 rebuild in Sweden

[RickK]

 

[larsli68]

Thanks Rick!
I really want to launch. It's just that so much other stuff comes in the way...

//Lars

[RickK]

Thanks Rick!
I really want to launch. It's just that so much other stuff comes in the way...

//Lars

Tell me about it (I know the feeling)

[larsli68]

Well, baby steps towards launch... My brother and nephew helped me move the Merc up two holes tonight. Together with the new Mercury Vengeance 18" pitch prop, I'm hoping to get
another 4 knots out of the motor. All according to my mechanic and racer buddy.

Launch is now planned for Friday afternoon or Saturday morning. All depends on the weather.

//Lars

[larsli68]

Finally launched today. Tested the new prop, and had some vibrations unfortunately... Not fun, but I switched back to the 17" pitch alu prop and the problem went away.
I will try to get the stainless steel prop balanced.



 

[RickK]

Weather looks great in that shot - plus you got her launched and can enjoy her now for a while.

[larsli68]

Hello Rick,

The weather has been a bit on and off today. I did take her out for a spin. GPS worked fine. Will do more tomorrow.

I'm a bit bummed over the Stainless steel prop... I will take it to a prop shop to get it fixed.

[larsli68]

I have a question. I'm thinking of using the new prop center adapter from the alu prop on my stainless steel prop today.
I used the center adapter that came with the stainless steel (used prop). I might try this today.

[fitz73222]

 Hi Lars,
Are you talking about the flo-torque center adapter? I'm assuming they are both the flo- torque II. Is it plastic or brass? There are different adapters for different props assuming the stainless prop is Mercury. Some use the flo- torque III or IV so make sure you use the correct adapter. This may be the cause of the vibration. Also make sure that you torque the prop nut to 55 foot pounds, if it's just snugged up it can vibrate.

[larsli68]

Thanks for the input!

I tried to use the torque adapter from the Alu prop (Merc) but the same vibration occurred. Now I'm back on the 17" prop, and will have to take this stainless Vengeance prop to a prop shop.
No such thing in my home town, but I will  bring it to Stockholm or Gothenburg.

We went for a small swing today. Posting some pictures.

[larsli68]

I have this kit. #835257K1
Everything fits just fine, feels solid, but the prop gives a weird noise when as soon as I put it in gear.

[fitz73222]

Hi Lars,
There is lots of discussion about prop rattle at low speed on Mercury's with certain props. My perception is that the gear ratio relative to pitch is the issue. In other words the prop tries to out run the gear ratio and over turns from interia into the gearset and causes a rattle condition. This is a common issue.

[larsli68]

You mean I would have this problem with a new prop as well?

I have read some forums now about the problem. Thanks for helping me understand it might not be a problem with the prop.

I will investigate if I have a III or IV hub.

Thanks,

Lars

[larsli68]

It turns out I have a flo torq II hub...

[fitz73222]

Hi Lars,
As you have discovered, this problem is not unique with stainless propellers on these engines. The aluminum propeller runs quiet at idle correct? It's also not unique to Mercurys either. My 60 Bigfoot Merc also does the same thing with stainless prop at idle. It has almost 800 hours on it so obviously the rattle hasn't hurt anything. What I had learn was it only had the rattle just in gear, so I got in the habit of bumping the throttle up to about 1000 rpm's in gear and the rattle goes away. I know this is annoying but you can get rid of it by changing driving habits when underway while driving at low speed.