AQ 280 Exhaust Bellows Replacement - Part Number Conflict

Hello,
Need to replace the exhaust bellows on my 1978 model AQ280. Stamped number on the current rotten bellows is "Volvo 897631". Yesterday I picked up a new-in-box VP kit from a supplier near Seattle. The kit box is stamped "Kit VOP 876631". Additionally the box label lists the bellows as VOP 872984 with an additional sticker 876631. The new bellows in the box is stamped "Volvo 872974".

The replacement bellows is obviously made of heavier material than the original, has the wire rings in each of the nine bellows grooves (the original only has rings in 3 grooves). The original has a drain port. The replacement does not have an obvious drain port.

Is the replacement bellow I bought the correct one even if the numbers don't match?

Thanks,
Mark

Pictures old and new bellows. New bellows much thicker and harder sides and has a wire ring in each groove.

Look closer there must be a hole. It looks like it will fit as long as the holes are the same size and fits in the groove on both sides with the hole pointing down.

The engine is a VP170. The outdrive is a AQ280. The boat is a 1978 Glasply. There is no back flow preventer on the outdrive or the bellows. Theprevious owner bolted on a piece of rubber on the exhaust port but it does not function to prevent back flow.

What's the downside to operating without a back flow preventer.

Thanks,
Mark

What appears to be a modified back flow preventer is bolted to the exhaust port and is not hinged and is only slightly flexible (picture attached). I guess I don't see the purpose of this setup. I had older fiberform a couple of years ago with a 270 outdrive. That outdrive had an actual hinged flapper that could cover the exhaust port.

I guess the bottom line is -- should I return the bellows I picked up yesterday and try to get a bellows with a built-in back flow preventer. The engine is an in-line 6 cylinder so exhaust restriction is not a issue (if I understand your previous message correctly). Or should I buy your "280 production model flapper"? Where are you located?

Thanks,
Mark

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shadetreevet said:

The engine is a VP170. The outdrive is a AQ280.
That would an AQ170 w/ 280 stern drive!

There is no back flow preventer on the outdrive or the bellows. The previous owner bolted on a piece of rubber on the exhaust port but it does not function to prevent back flow.
What I see in the photo looks to be an actual and rare 280 production model back-flow-prevention-flapper.
It appears to have been over-heated........ and it looks as though it is done!


What's the downside to operating without a back flow prevention flapper?
The down side would be water entering an open exhaust valve.
This could occur from exhaust gas reversion, or during a quick and while-moving shut-down, or from a wave surge from another boat, or from several other unwanted situations.
When water enters an open exhaust port, the valve is cooled quickly, often distorting the valve causing the need to remove the cylinder head, etc.
In an extreme scenario, you may end up with even further damage.


Thanks,
Mark

Click to expand...

shadetreevet said:

What appears to be a modified back flow preventer is bolted to the exhaust port and is not hinged and is only slightly flexible (picture attached). I guess I don't see the purpose of this setup. I had older fiberform a couple of years ago with a 270 outdrive. That outdrive had an actual hinged flapper that could cover the exhaust port.


I guess the bottom line is -- should I return the bellows I picked up yesterday and try to get a bellows with a built-in back flow preventer. The engine is an in-line 6 cylinder so exhaust restriction is not a issue (if I understand your previous message correctly). Or should I buy your "280 production model flapper"? Where are you located?

Thanks,
Mark

Click to expand...

As said earlier...... I think that the exhaust bellows with the internal flapper creates a restriction.
The easily available 290 flapper can be purchased over the counter, and can be retro-fit to your 280 with a small amount of work!
The 280 flapper that I have needs to be removed from the case it's attached to ....... but I'd do that if it would help you! Six SS pop-rivets and you'd be back in business!!!!!!

Rick east of Portland OR.

Hi Rickm
When would your 280 flapper be available and how much do you want for it?

Thanks,
Mark