95 5.0 Regal blew apart new exhaust bellow

Status
Not open for further replies.

Bruce ma

Recruit
Joined
Jul 1, 2015
Messages
2
Hello, I am new to working on boats and am looking for a little help. Last week I replaced the exhaust hose and bellow on one side of the engine due to the old one being split. After 10 minutes of run time the new bellow is burnt inside and blown apart. There was water spraying out when the old one was torn so I assume the manifold is working correctly. My initial thought was clogged y pipe, but why is it burnt?
 

dypcdiver

Lieutenant Junior Grade
Joined
Nov 1, 2005
Messages
1,016
Really could do with a few details of what we are working with ie. type of engine and outdrive.

Sounds as if you may have a several possible causes,

Firstly have you checked the raw water pump impeller? might just be worn out.
Secondly check that the water outlet from the thermostat housing to the fwd end of the exhaust manifold is clear at both ends, as with time they can rust up and reduce the flow.
Thirdly make sure that the flapper valve is free to swivel. Located in the upper part of the legs of the "Y"
Finally I once found a lump of rusty metal in the exhaust just where it enters the outdrive. It was so much of a restriction that reduced my WOT to 3800rpm.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,309
which did you replace, the exhaust hose between the manifold and the y-pipe, or the bellows between the transom mount and the out drive?

did you buy a genuine volvo penta bellows, or a sierra aftermarket?

if the exhaust hose is split, my first thought is that there is not enough water going thru the manifold. either due to rust inside the manifold, or due to blockage up stream or simply really low flow.
 

Bruce ma

Recruit
Joined
Jul 1, 2015
Messages
2
I replaced the exhaust hose from the manifold to the metal elbow and the one to the y pipe. Before replacement I did fire the boat up while it was in the water and their was water coming out from the manifold. I don't know that its enough, but their was some flow. Is it possible their is something in the y pipe causing a blockage? My thought was that if the y pipe was blocked it would fill up with water and that wouldn't explain why the rubber was all burnt. I did buy original Volvo Parts
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,309
Some flow? Should be about 10 GPM minimum per side. If the exhaust hose is burnt, you have a water flow issue.... Period
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
This... "while it was in the water and their was water coming out from the manifold" is concerning. There should not be any water visibly coming out from under the manifold. To me that sounds like the drain plug on the (exhaust) manifold is open and not enough water is going thru the exhaust gas stream.
 

PatinIdaho

Chief Petty Officer
Joined
Oct 7, 2014
Messages
405
Im reading it as.
He fired it up before putting the hose on.
So naturally water would come out.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Well, water would not come out visibly from "the manifold", could be a misuse of terminology I guess
 

TheHammar

Recruit
Joined
Apr 25, 2021
Messages
1
Any conclussion to problem with the blown Bellow? I Might have had the same problem on my VP AQAD41 with drive DP290.
 
Status
Not open for further replies.
Top