Hi,
Everyones been really helpfull in answering my questions before. However I have a big problem with my Volvo Penta 4.3GL with Corba SX stern drive fitted in a 175SX Wellcraft Excel.
I've writen off the engine due to seawater flooding the clyinders and sump
Pulled exhaust manifolds and risers both side look badly corroded but NO obvious signs of leaking. Before I replace my engine I want to be sure I've done everything I can to prevent another water ingress problem. I plan to replace the manifolds and risers, however with no flapper valves fitted to the exhaust this just fills me with fear that I could get seawater back up the exhaust.
I have seen this 'closed thread' posting from a year ago;
There are a few problems, !st , the risers in most boats are very low but just increaseing the height of the risers alone will not cure the problem of hydro locking the engine( which can destroy an engine) 2nd, the flapper valves that were installed in the Ypipe are prone to failure, when they do, they have a tendancy to block the exhaust port that runs through the center of the propeller when this happens the only exhaust port that is open is the small port at the base of the transom. Having a partially blocked exhaust will cause poor performance and somtimes engine heating, also as the port at the transom is the only exhaust port when stopping theboat the presure that builds up at the transom is enough to push water up and over risers even with the riser extentions added. 3rd, if you find that your flappers are missing you cannot just replace them, you need to be sure that the old ones are not blocking the exhaust at the base of the Y pipe which is where they end up generally., 4th volvo no longer makes the valves available but you can use the one from mercuiser but even those will fail at some point. 5th ,the only sure fix is to run through the transom exhaust bells with external flappers, which is a conversion that I am presently doing on a 97 celebrity with a 4.3 engine that I have just rebuilt due to this problem , the old engine was a complete loss. I hope this post will help others with this problem
I will check all the above but wanted someone to explain the conversion that's mentioned in the 5th point. Can this be done and wants involved ?
Thanks, any advice welcome.
Everyones been really helpfull in answering my questions before. However I have a big problem with my Volvo Penta 4.3GL with Corba SX stern drive fitted in a 175SX Wellcraft Excel.
I've writen off the engine due to seawater flooding the clyinders and sump
Pulled exhaust manifolds and risers both side look badly corroded but NO obvious signs of leaking. Before I replace my engine I want to be sure I've done everything I can to prevent another water ingress problem. I plan to replace the manifolds and risers, however with no flapper valves fitted to the exhaust this just fills me with fear that I could get seawater back up the exhaust.
I have seen this 'closed thread' posting from a year ago;
There are a few problems, !st , the risers in most boats are very low but just increaseing the height of the risers alone will not cure the problem of hydro locking the engine( which can destroy an engine) 2nd, the flapper valves that were installed in the Ypipe are prone to failure, when they do, they have a tendancy to block the exhaust port that runs through the center of the propeller when this happens the only exhaust port that is open is the small port at the base of the transom. Having a partially blocked exhaust will cause poor performance and somtimes engine heating, also as the port at the transom is the only exhaust port when stopping theboat the presure that builds up at the transom is enough to push water up and over risers even with the riser extentions added. 3rd, if you find that your flappers are missing you cannot just replace them, you need to be sure that the old ones are not blocking the exhaust at the base of the Y pipe which is where they end up generally., 4th volvo no longer makes the valves available but you can use the one from mercuiser but even those will fail at some point. 5th ,the only sure fix is to run through the transom exhaust bells with external flappers, which is a conversion that I am presently doing on a 97 celebrity with a 4.3 engine that I have just rebuilt due to this problem , the old engine was a complete loss. I hope this post will help others with this problem
I will check all the above but wanted someone to explain the conversion that's mentioned in the 5th point. Can this be done and wants involved ?
Thanks, any advice welcome.
