Bad Exhaust Flapper Twice in 18 months. WHY?

[lmannyr]

Last year, when I took the alpha 1 down, the flapper was in the exhaust tube. I replaced both flappers and moved on. Yesterday I took 1 hour (at most) of engine time idling to the favorite spot. When flushing the engine at home I noticed pinging from the exhaust. The engine was warmed up at home PRIOR to the trip and this pinging was NOT there.

I'm guessing one of the flappers is melted and needs replacement again. My questions is WHY SO SOON? I'm I overheating? The temp gauge when cold goes from the far left to a max of vertical, never more when warm. Oil pressure is Mid range always too. I'm due for oil change, last was last year.

Any help or suggestions would be appreciated.

 

[Maclin]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

I'm guessing one of the flappers is melted and needs replacement again.

I would try not to guess anything before I knew for a fact that the exhaust flapper is the problem now.

A lean mixture can cause pinging, and a lean mix also cause the exhaust gases to be hotter.

 

[WizeOne]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

....also a restricted water flow. Does the risor feel hot?

 

[JustJason]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Inside of each flapper, under the rubber, there is what looks like a metal tab that you would screw to the bottom of a tap shoe. Each flapper has 2, for a total of 4 metal tabs. You normally dont see the metal unless the rubber was burned off (overheated exhaust) the old ones or they are seriously aged. When you did your old flappers when they came out where they complete? If not you probably have the old metal tab (or 2) sittin there in the collector. Next time you pull the drive off you'll be able to pull them out.

 

[7-c's]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

after seeing this link posted before, i will think twice before replacing my flapper valves if/when they go bad- http://www.4shared.com/file/51149475/c49b77de/Volvo_Exhaust_Flapper_valves.html?cau2=403tNull

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Interesting article. Wonder why Merc hasn't followed suit? So what is the recommendation for the this? replace or follow volvo article?

 

[Don S]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

You have a Mercruiser, why would you follow a Volvo bulletin? Completely different companies.
Did you put the new style flappers in your Mercruise, or aftermarket that were like the original parts that didn't work very long ???????

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

originals....

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Buzzer doesn't work so I'm also working on that on another thread.

 

[Don S]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

originals....

Maybe you should get the real thing.

PS: The flappers have nothing to do with any alarms.

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Originals meaning mercruiser flappers.

I was thinking maybe I missed an overheat ( I really doubt it ) so I'm working on the alarms to get them working. Never worked since I got the boat.

 

[Bondo]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Ayuh,... Depending on the condition of the manifolds/ risers,...
You could still have a water Flow issue without an Overheat condition...

A lack of water flow thru the exhaust will Smoke the shutters in No time...

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Today, after replacing the Thermostat and sleeve, and moving the water heater intake from the engine water pump to the thermostat housing I noticed the port riser is too HOT to keep my hand on it for more than 3 secs.

The water heater is still not hot. The water heater out hose goes to the port riser.

Both Manifolds are very cool, and the starboard riser is essentially the same temp as the manifolds. The port exhaust hold on the stern is like 10% or less compared to the starboard hole.

How should I proceed? Thanks!!!

 

[Bondo]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

The water heater is still not hot. The water heater out hose goes to the port riser.

Ayuh,... My guess is,... it's hydro-locked...

If you move the Heater's return line to the Circulating waterpump as I noted,...
It creates a low pressure area, combined with the hi-pressure area in the Intake manifold, it'll heat your water...

Where, Exactly did you put the fitting in the T-Stat housing,..??
Is it on the Intake manifold side of the T-Stat,..??
The squarehead pipe plug in your intake manifold is where it Should be...

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

I have the 4 port T-house. The Water Heater intake hose is beneath the starboard manifold hose on the t-house.

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

...noticed the port riser is too HOT to keep my hand on it for more than 3 secs.

Both Manifolds are very cool, and the starboard riser is essentially the same temp as the manifolds. The port exhaust hold on the stern is like 10% or less compared to the starboard hole.

How should I proceed? Thanks!!!

Any suggestions?

 

[Bondo]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Any suggestions?

Ayuh,.... Reroute the waterheater plumbing,+ put the Stock plumbing back where it Belongs would be a Great start....

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Alright, the water heater hoses are set: one going to top of engine water pump, and other going to the T-STat house like in Manual 24 pg 6a-23.

Water is a tad above room temp, much warmer than the cold side for sure. This is after engine warm up. So I shut down and heating the water with electric part of water heater and see the difference.

Get this though, now the starboard side riser is HOT and port cool. The starboard water exhaust is hot/very little and port is cool and plenty! THE EXACT OPPOSITE from when I ran it earlier!!!

What the hell?

 

[Lodgepole]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

With all the "space age technology???", ther is no excuse for not marketing a bullet proof flapper. Considering the price the marine industry charges for parts, there is no excuse.

 

[lmannyr]

Re: Bad Exhaust Flapper Twice in 18 months. WHY?

Water is a tad above room temp, much warmer than the cold side for sure. This is after engine warm up. So I shut down and heating the water with electric part of water heater and see the difference.

Yup, water is REALLY HOT using it's electrical heating element.