how critical is exhaust flap? Volvo 270

[2stroke1971]

Pardon my ignorance, but this is my first I/O boat. On a Volvo 270 outdrive, how critical is the exhaust flap? I was testing the motor and a backfire blew it off. The holes are rotted, and whats worse is that the screws that held it on are nothing but corroded nubs at this point. So, even if I put some washers on the old flap, or got a new flap, the screws are all but gone and wont come out Im sure.

So what purpose does the flap serve? I figure I could drill out some holes and put some nuts and bolts thru a new flap, but Im hoping to test the boat on the wter this weekend, and Im not sure if I will have time to get a new flap and put it on.

Am I likley to screw things up royally if I go out a couple times with no flap?
Thanks,
Neil

 

[JoLin]

Re: how critical is exhaust flap? Volvo 270

There's a V-P service bulletin floating around somewhere on this subject. Try google. The gist is that they did away with it because they decided it was troublesome and ineffective.

However, do look for it- my memory can also sometimes be troublesome and ineffective

 

[captmello]

Re: how critical is exhaust flap? Volvo 270

I would fix it if I were you. Its there to help prevent water from flowing back up the exhaust.

Unfortunatly, someone else was asking about it the other day and I couldn't find a part number for it. Maybe somone else knows.

 

[83Evinrude]

Re: how critical is exhaust flap? Volvo 270

Here is the Service Bulletin about removing it:
http://www.marinepartsexpress.com/jpg/Flapper Parts Bull.jpg

 

[Don S]

Re: how critical is exhaust flap? Volvo 270

That service bulletin is for a completely different drive (SX and DP-S) , not the 270 that you have.
The flapper is there to prevent stern waves, wakes and such from pushing water up the exhaust sysem and into the exhaust manifold, and getting water into the cylinders with open valves when the engine is NOT running.
The part number for a new exhaust outlet is 854061.

 

[captmello]

Re: how critical is exhaust flap? Volvo 270

Wow, $275 part on another site that has "dealer only" oem parts. That must be for the housing and flapper. Better check ebay or look for used parts elsewhere.

Let us know what you find.

 

[tony0795]

I have a 1976 Volvo Penta outdrive on my bayliner Skagit. I see where screws would go and the exhaust flap or cover is missing. Can anyone have the part number for this year outdrive?

 

[bruceb58]

You should start your own thread and ask your question.