Mercury 115 EFI 2015, white "plastic ring" in front of propeller, what is it for?

[jmkvalsund]

Se attached image, the white plastic ring in front of the propeller is supposed to to be squeezed into the underwater housing in front of the propeller. Now it has become loose, and neither me or my local boatrepairman can understand its purpose. Anyone who knows? The motor seems to work fine even if it is loose, but I'm wondering if a small decrease in speed vs rpm can be because of this?

Regards,
John M

 

[jimmbo]

It is used to provide a better seal to reduce/prevent Exhaust Gases from exiting at that location an causing Havoc for the Prop

 

[jmkvalsund]

It is used to provide a better seal to reduce/prevent Exhaust Gases from exiting at that location an causing Havoc for the Prop

Thanks a lot, that makes sense. That can explain the small loss of speed vs rpm. Since I'm not able to get a new one immediately, what is the better option: Just let it hang around, or try to get it off using a knife/pry-bar, whatever that doesn't damage the propeller?

 

[jimmbo]

How about taking the prop off, and using a small hammer, and a small dowel, either tap it on the prop or tap it off and then reposition it on the gearcase. Reinstall Prop

 

[jmkvalsund]

How about taking the prop off, and using a small hammer, and a small dowel, either tap it on the prop or tap it off and then reposition it on the gearcase. Reinstall Prop

I supposen I could do that, but then I have to get the boat out of the water...
Is it just tapped on place, no hooks or latches or whatever?

 

[jimmbo]

Can you float the boat close to a shore or beach, wade into the water with a couple of tools in hand? I did that when I needed to change props. I have also anchored the boat so that the fully tilted up engine was close the dock, and changed the prop

 

[jmkvalsund]

Can you float the boat close to a shore or beach, wade into the water with a couple of tools in hand? I did that when I needed to change props. I have also anchored the boat so that the fully tilted up engine was close the dock, and changed the prop
View attachment 366046

Thanks again, I'll try that!

 

[QBhoy]

Hi. There is a known issue with these on early 115’s and 150’s for sure. My 2016 115 had it come loose. Lots online about it. Can make your engine have exhaust bubbles across the prop blades. Sounds like a misfire at low rpm and can reduce performance at top end too. I saw both. Ended up glueing it back in place. But I believe there is a service bulletin about it and a better modern part has been made. But I thought it was only a. Issue with the large gear case. Like the 115 Ct has. Is yours a CT ? Prop looks very small to be a Ct.

 

[jmkvalsund]

Hi. There is a known issue with these on early 115’s and 150’s for sure. My 2016 115 had it come loose. Lots online about it. Can make your engine have exhaust bubbles across the prop blades. Sounds like a misfire at low rpm and can reduce performance at top end too. I saw both. Ended up glueing it back in place. But I believe there is a service bulletin about it and a better modern part has been made. But I thought it was only a. Issue with the large gear case. Like the 115 Ct has. Is yours a CT ? Prop looks very small to be a Ct.

Hi, this is not the CT model, but the standard gearcase. So you glued it up using kind of multibond glue then? How far in is it supposed to be, are there any positionmarkers or does it stop in some other sealings?

 

[QBhoy]

Hi, this is not the CT model, but the standard gearcase. So you glued it up using kind of multibond glue then? How far in is it supposed to be, are there any positionmarkers or does it stop in some other sealings?

There are insets that it sits in. Clips into place with the wee lugs on it. The lugs tend to be the thing that lets them down. Don’t hold in place. Give it a while to set before putting the prop back on. It might disturb it