changing exhaust flappers on land or sea

[CayugaCobalt]

This may be a silly question, but, can I replace my exhaust flappers (aka shutters) with the boat in the water? Or must it be done out of the water?

I presume the answer is it depends if they are above or below the water line?

I didnt have a tape measure, but I estimated, mine are 1" above the water line.

I have 7.4L MPI in a 1997 Cobalt 233.

 

[Rick Stephens]

That's gettin mighty close. Your presumption is exactly correct.

 

[Scott Danforth]

This may be a silly question, but, can I replace my exhaust flappers (aka shutters) with the boat in the water? Or must it be done out of the water?

I presume the answer is it depends if they are above or below the water line?

I didnt have a tape measure, but I estimated, mine are 1" above the water line.

I have 7.4L MPI in a 1997 Cobalt 233.

1" above the water line in a static situation quickly becomes 1" below the water line with any wave or you walking about the boat.

 

[Bondo]

This may be a silly question, but, can I replace my exhaust flappers (aka shutters) with the boat in the water? Or must it be done out of the water?

I presume the answer is it depends if they are above or below the water line?

I didnt have a tape measure, but I estimated, mine are 1" above the water line.

I have 7.4L MPI in a 1997 Cobalt 233.

Ayuh,.... I've done it, at the dock, on a very calm day, with no marina traffic,.....

 

[Lou C]

I would not if you’re in a location with any boat traffic or wind. What will you do if water starts flooding into the boat? The bilge pump should take care of it but that’s like having two 3” holes in the hull, a lot of water could come in!

 

[achris]

Have the bilge pump on standby...

 

[MichaelBC]

Maybe let a few heavy people sit on the bow ?

 

[achris]

Maybe let a few heavy people sit on the bow ?

Ahhh, correct use of ballast.

 

[CayugaCobalt]

1" above the water line in a static situation quickly becomes 1" below the water line with any wave or you walking about the boat.

Hi Scott: you and Bondo have wisely advised me many times. What is the bigger risk A or B?

A) change flapper at dock as a newbie who has never done it with aforementioned 1" clearance above water line

B) pull/drive boat out onto trailer on ramp at lake marina, which in my experience tilts nose up and sinks stern down more than 1" with the suspected half burnt flapper still in there?

I Overheated engine once for ~2 minutes and the lower rubber exhaust tube/hose turned kinda brown on outside but seems pliable still. THis event has prompted me to want to change flapper.

 

[achris]

Those exhaust shutters aren't a watertight seal (even when brand new). If you haven't had any water ingress (in through the exhaust) problems in the past, then you wouldn't have any now. My preference would be to trailer the boat and do the job without risk.

Chris

 

[CayugaCobalt]

Those exhaust shutters aren't a watertight seal (even when brand new). If you haven't had any water ingress (in through the exhaust) problems in the past, then you wouldn't have any now. My preference would be to trailer the boat and do the job without risk.

Chris

Thanks for that input, good to know. Just being cautious because those are likely 24 yr old flappers that now have now seen some extra heat and I have put zero minutes on the boat since the overheat. So basically its a trust issue, which I have in many areas of my life LOL
Plan is likely to be put it on trailer and do it the driveway. Just waiting to hear what Bondo and Scott say.

 

[Bondo]

Thanks for that input, good to know. Just being cautious because those are likely 24 yr old flappers that now have now seen some extra heat and I have put zero minutes on the boat since the overheat. So basically its a trust issue, which I have in many areas of my life LOL
Plan is likely to be put it on trailer and do it the driveway. Just waiting to hear what Bondo and Scott say.

Ayuh,.... Whatever trips yer trigger,.....

If yer super concerned,. Load it up, pull out til the drive is still in the water, 'n crank it over,......
If it cranks over, there's no water in a cylinder,.....
If it starts, shut it off after a second or two,....
'n remember, the impeller is at the top of the lower unit, 'n it needs a flooded entry,....