Volvo Duoprop Exhaust Shutters

[harmony]

I have a 1995 7.4 GL with a Duoprop and just lost 800 rpm. I would not be surprised if one of the exhaust shutters has broken free. I realize that Volvo no longer uses the ehxhaust shutters and am going to open things up to remove them in any case. The boat is lift kept so there should be no problem, but I have the following questions. Does Volvo use a sealant on the exhaust bellows? How far can a shutter drop if it does break free? Can it enter the drive or will it stay in the bottom of the exhaust tube? If it can enter the drive can it be fished out without removing the drive?

Many thanks.

 

[crestapre]

Re: Volvo Duoprop Exhaust Shutters

There is no need for sealant on the exhaust bellows. They have holes designed into them for back pressure or draining anyway. Many people have run w/o them. I suggest that you use the exhaust bellows, if you remove the flappers. This will help to restrict the water from flowing up into your engine.

I have twin 94 VP SX drives that I have removed my flappers from also. I had found one in the exhaust port of the outdrive and was able to remove it with a set of long needlenose plyers. I did not have to remove the drive as I could see it from the exhaust port under the cav plate of the drive. The others were removed when I changed the manifolds and risers.

You will have to seal off the pivot holes in the y-pipe with RTV or silicone before you put the rubber exhaust boots back on.

 

[harmony]

Re: Volvo Duoprop Exhaust Shutters

Thanks;

I guess I will have to open it up and see where the shutter wound up and take it from there. That is if I actually lost a shutter. No matter what I am going to pull them.

Thanks again