Rubber Exhaust Flap!

[kashurst]

Started looking at the actual boat bits on my fairline project. It has AQ 270 outdrives. One of the exhaust flaps is missing.
It seems that the part is no longer available.
It also seems there are exhaust bellows available with built in exhaust flaps - are they any good?
It's a pretty simple part, so I could make one from nitrile rubber sheet with a bit of imagination using the other one as a template.

How important is the flap? Thanks all.

 

[DavidJ]

Bit of a risk assessment
There must be hundreds of leg owners with missing flaps with no issues, however if water does get back up into the cylinders it’s a very dead engine. (bent con rods etc)
I‘d be tempted to DIY
Are there flaps from other VP outdrives which are similar (which may be available) that you can modify?

……or play it absolutely safe and buy the bellows with a flap in, assuming of course it does the same job ????

 

[stelican]

Started looking at the actual boat bits on my fairline project. It has AQ 270 outdrives. One of the exhaust flaps is missing.
It seems that the part is no longer available.
It also seems there are exhaust bellows available with built in exhaust flaps - are they any good?
It's a pretty simple part, so I could make one from nitrile rubber sheet with a bit of imagination using the other one as a template.

How important is the flap? Thanks all.

In the 1980s I worked for a Fairline dealer and we sold quite a few Corniches so I am following the thread with interest.
What engines do you have in your Corniche?

 

[Daydream believer]

..

 

[kashurst]

In the 1980s I worked for a Fairline dealer and we sold quite a few Corniches so I am following the thread with interest.
What engines do you have in your Corniche?

a pair of lightly used petrol AQ 125 - so pottering about speeds.

 

[stelican]

a pair of lightly used petrol AQ 125 - so pottering about speeds.

I recently saw a 1991 price list and the Corniche was offered with Aq 125 with 280 drives.
I cannot remember seeing the 270 drives on a Corniche.

 

[kashurst]

I recently saw a 1991 price list and the Corniche was offered with Aq 125 with 280 drives.
I cannot remember seeing the 270 drives on a Corniche.

mine is a 1985 model. Definitely 270's with the electric lift.

 

[Sianna]

DP290 outdrive on mine, the rubber exhaust flap fell off a few years ago, no problems without it, checked with our local VP service centre they agreed that they don't do much...

 

[Chris_d]

DP290 outdrive on mine, the rubber exhaust flap fell off a few years ago, no problems without it, checked with our local VP service centre they agreed that they don't do much...

Many years ago a forum member with a Leader 805 hydraulic'd his KAD44, he was in dispute with Volvo for ages about it because they said he had stopped too quickly off the plane and the water had gone back up the exhaust flooding the engine, problem could have been prevented by the rubber flaps which must have fallen off.

I found a company on Ebay selling them and they are easy to fit with long pop rivets, agree 99% of the time they don't do much but worth doing if you can find them just in case.

 

[Scubadoo]

DP290 outdrive on mine, the rubber exhaust flap fell off a few years ago, no problems without it, checked with our local VP service centre they agreed that they don't do much...

If the VP service centre thinks it doesn't do much, then why would VP have it in their design. I think most of the time as Chris_d has mentioned, and as you have experienced, it is not a problem, however I would not risk it. It only takes one "odd" event to potentially write off your engine, it is far easier and cheaper to replace the rubber part then an engine. Mine (DPE/290) rubber flap was replaced when I noticed it was starting to split.

If the 270 part is not available, then I would attempt to modify the DPE/290 rubber flap to fit the 270 drive.

 

[QBhoy]

Seen loads with them missing. Could easily make one I suppose. Just don’t reverse at silly speeds in the meantime .
On some VP engines (but not all, especially around a certain era), there was an exhaust flapper incorporated between the down pipe from the engine riser and the inner transom assembly. More common on the GM engines. But like I say, there was a period when there wasn’t any there fitted. Even on the same engines that were used In mercruiser form, that did.

 

[Mr Googler]

the flap doesn’t matter when the engine is running in my mind.

Matters when moored and a 4 knot tide up your backside…especially if the boat sits low at the back. I’ve seen a few where the water level is in the rubber exhaust section at rest!