Exhaust shutter project

zaverin1

It’s  pretty rare to find pieces in the exhaust.

212rowboat

zaverin1 said:

It’s  pretty rare to find pieces in the exhaust.

my experience is contrary to this.  that is usually how you find out, unless you pull the boots off. 

aero3113

I had this happen to me on two different boats, pulled the drive off to service and they were sitting right there. Also If you are losing RPM's and/or overheating and cant figure out why, check for broken shutters blocking the exhaust.

Michael T

The flappers are a serious contender for overheating woes. I posted a year or so ago about an American boater visiting the Kingston marina in Canada who had the problem and my friend (Doug Hyde - manager George's Marine Pride marine Group) let him stay at a marina slip NC on the Sunday and did the repair ahead of the work order queue on Monday morning. He was on his way with another American boat by early afternoon.

Stodge

What's the expected life span of the flappers?  I don't recall hearing about them being regular maintenance items like impellers.

212rowboat

there is really not much to the flappers.. they are just rubber across a hinge, with a backing plate on them.  they seem to 'last' dependent on construction, and forming rubber, as you can guess, is anyone's guess.... some are good, some are not as good, and in the same packaging right beside each other. 

the issue seems to stem from them hanging up in the pipe- they 'grab' the pipe and don't flap... because they don't flap heat tears them up even worse, and they either break of become fully lodged in the pipe... if they break free they often get stuck in the exhausts strange shape nearing the bellow, and can be seen/plucked out of there... otherwise they're blown right out.  when one side 'flaps' and the other is stuck, you'll have heat issues on that riser/bank of the engine... the risers ought ot be close in temperature, but one side generally is a bit warmer than the other even on a healthy engine, but not significantly so... it's especially evident on the top of the Y pipe when one is stuck- it'll be quite a bit hotter than the other. 

if you want to check, an easy way to do this is with a vacuum gauge and comparing the reading to a chart referencing it's behavior when there is excessive backpressure... that BP is what generates the heat... the gauge will tell you that there is excessive back pressure, and unless your manifolds and/or risers are shot, it's gotta be flappers or some obstruction at the exhaust tip (under your outdrive). 

Liberty44140

I'll post pics once I finally get to and see my 11-12 year old shutters. I am doing them proactively, no known issues. 

zaverin1

They last a long time 
salt water or no water flow will cause premature failure 

212rowboat

you guys ever heard of the wash basin graph of failure?  it's when an item has a high rate of failure early represented by a spike in the graph, then a low long line flat as a pancake, followed by another spike in failure rates at the end.  it basically denotes that craftsmanship or production causes the initial high rate of failure, but the products that are properly manufactured or installed have long steady periods of performance until they kick out the ghost.  

these things follow that graph... 

if you make it through the first 100 hours or so, you're likely going to make it years and years with them.  if they fail they're likely going to do so fairly quickly. 

GMSLITHO

so what your saying is .........do you feel lucky 

Trashman

When stuff would break my dad used to say it was made on a Monday or Friday. Lol

Liberty44140

Success! The hair dryer made all the difference. Was ready with soap and water but no need. Used larger hose pick to loosen and hair dryer and all set. 2 hours total for both engines. The old shutters were in good condition, I could have gone at least a couple more years, but glad it’s done.

aero3113

Great! Now you know you are good!!

Michael T

......yes, the hair dryer - I believe I said :-)

Handymans342

Diesels dont have that crap. LOL

Liberty44140

Handymans342 said:

Diesels dont have that crap. LOL

Thanks Handy! Was getting worried that we were going to get through a thread solely about a gas engine with no mention of diesel, thank you for making sure that the I is dotted! 

Liberty44140

Michael T said:

......yes, the hair dryer - I believe I said :-)

Thanks MT, worked great. 

Handymans342

Liberty44140 said:

Handymans342 said:

Diesels dont have that crap. LOL

Thanks Handy! Was getting worried that we were going to get through a thread solely about a gas engine with no mention of diesel, thank you for making sure that the I is dotted! 

Hate to rub it in LOL

Handymans342

I get no other support from my diesel brothers out there either

reneechris14

I'm going to send the camera up though the Y pipe before I put the drives on next week I hope I'm as lucky as you or I'll be in there with admiral's hair dryer. Good job @Liberty44140

Liberty44140

Thanks guys! Hoping that all of this preventative maintenance brings a trouble free summer. Wishful thinking on a boat!