exhaust shutter 4.3L

[tystick]

1990 merc 4.3L<br />After reading archives, there is mention of the 4.3L having problems with shutters not working.<br />I have possible issue with shutters. I stalled out coming into dock for no apparent reason. Are they prone to wear out?<br />Are they servicable item? They look like easy to replace.

 

[bigbrownbuku]

Re: exhaust shutter 4.3L

they are very simple to replace. you need the shutter kit and 2 riser gaskets. when you pull the exhaust rubbers to get at the shutters and they era gone chances are they got stuck at the bottom of the y pipe and could be blocking your exhaust.

 

[Chris1956]

Re: exhaust shutter 4.3L

Ty, One of my shutters broke years ago. I found the pieces in the exhaust passage when I pulled the drive. They didn't block the exhaust noticably. The dealer said it was optional to replace them. I did not replace, and have not had any issues.

 

[tystick]

Re: exhaust shutter 4.3L

Chris<br />Optional to have exhaust shutters?<br />I would think the cylinders would potentially get water in them.<br />when you say exhaust passage - I would have to pull the gimbal bearing to see?<br /><br />What is part # for shutters for my engine.<br />I do not have access to boat to check. It looks like maybe what they call bat wings?

 

[bigbrownbuku]

Re: exhaust shutter 4.3L

merc still make repalcement shutters and the jury is still out as to how effective they can be in some boats. the exhaust doesnt go through the gimbal. the drive should be pulled if you have missing pieces.

 

[tystick]

Re: exhaust shutter 4.3L

I thought shutters prevent stall out as boat slows down and water is rushing in from back.<br />How long does the jury take? <br />Have they been sequestered?<br />Should i not worry about replacing them?

 

[Chris1956]

Re: exhaust shutter 4.3L

Ty, Yes, the exhaust shutters are supposed to help stop water from getting into the risers/manifolds/engine when slowing down abruptly (out of gas, engine seize...). I never replaced the one that broke, and although I have had some abrupt slowdowns of the boat, I have not had any issue. I found the pieces of the shutter in the exhaust passage when I pulled the drive at the end of the season (10+ years ago)

 

[bigbrownbuku]

Re: exhaust shutter 4.3L

the shutters are just a 1 way valve, exhaust and water out only. they dont prevent stall out.<br />the fact remains, if your riser height is correct at around 14" above at rest, you should never have a problem. remember, people sitting at back make a difference.<br /><br />if you have 1 piece manifolds and risers, replace them.