Mercuriser Exhaust Manifolds

[DestinyEscape]

Hey Guys,<br /><br />If any of you happened to catch the thread on my hydrolocking problem then you'll have an idea of what I'm talking about here. I thought that possibly my exhaust manifolds were going bad, but when the problem didn't seem to surface again, I kind of figured it was all just a freak coincidence.<br /><br />Anyway, the engine hydrolocked this weekend on the water again and I pulled the plugs last night and half the lake seemed to drain out of my cylinders. I pulled the exhaust manifolds and they are pretty trashed. It is obvious that they need to be replaced. My problem is that these parts are pretty expensive ($523 each from mercruiserparts.com) and I really cant afford $1100 right now.<br /><br />My question is whether or not I can go with a different manifold (I have the ones that look like a block where it bolts to the exhaust ports and then has a very large tube coming around the front and over the top towards the rear and connect to a rubber hose that leads out the stern drive unit). I have seen a manifold that looks like a block with a tube coming straight out the back and this seems to be the more popular style (judging by how few web sites on the internet carry my type compared to the other). I didn't know if it was possible to install some type of conversion kit or somehow make that type work in my application as this type is significantly less expensive.<br /><br />If that's not possible, does anyone know where I might be able to get a better deal than $523 each? Any help would be greatly appreciated as always.<br /><br />CP<br /><br />Boat/Engine Specs:<br /><br />18' Marada Fish/Ski (1997)<br />4.3LX (Gen +) 2 Bbl.<br />Thunderbolt IV Ignition System<br />AlphaOne Stern Drive Unit

 

[zzzzz]

Re: Mercuriser Exhaust Manifolds

Even if you did want to change the two piece exhaust system,you'd have to change the "Y" pipe I believe and they wouldn't be any cheaper-actually more expensive-about $580 per side plus the Y...email me and I'll see what I can do on the one piece gulfcoast5300@earthlink.net

 

[a.d.mobile]

Re: Mercuriser Exhaust Manifolds

Sure you have the problem solved? engine running properly? flapper valves still there? seems if manifolds were bad it would never had re-run properly after the first time. would have kept it up after the first drowning. have you froze the manifolds and repaired them? before i guesed at 1100.00 i would spend 150.00 at max for proper diagnoses at a shop.

 

[a.d.mobile]

Re: Mercuriser Exhaust Manifolds

oh i see a 97 4.3 v6 the problem is one g/m denies to much valve over lap causing to much exaust vaccum pulling in water when engine is shut down. if you can get a volvo dealer to talk to you they have a fix venting the risers to the carb using a modifed exaust decell valve form the 80s cars. This problem is real bad in short low draft boats with a high static water line (rear of boat to low in water)was engine off when it drown? or did you shut off when a backsplash wave hit the back of boat? look at youre rizer is there a plug facing the carb? it will have a big allen head to remove. there might not be with merc volvo was saved by omc old carry over design. there is some info out by merc i think but they do not make it easy. when this happens be careful i have seen broke starters spun ring gear on flywheel and bent rods from cranking with water in cyls.....

 

[DestinyEscape]

Re: Mercuriser Exhaust Manifolds

a.d.,<br /><br />Hey man thanks for the replies. It actually happens that my friends dad owns a marina out by Topsail Island in NC and an auto repair shop here in Raleigh and he looked at it. The engine runs ok. He told me that it was possible that the problem would not re-occur immediately due to the fact that the exhaust valves may not always be open in the same spots every time you shut off the engine. I would tend to agree since it was not the same three cylinders holding water this time. The problem has occured both times after shutting down the motor to allow re-entry by a skier or boarder and then it will not re-start. Last time the starter got thrashed, but not this time luckily.<br /><br />My buddy's dad acutally called me back a short time ago and he can get the manifolds for $388 each so I will go ahead and replace them.<br /><br />I always fully winterize and pull all of the manifold and engine drain plugs (not sure if that's what you meant by frozen) but they do have severe rust where the gasket was and all inside where the exhaust ports empty into.<br /><br />zzzzz,<br /><br />I appreciate the offer on finding a price and the advise on not switching, after doing more research I discovered that it would be much more expensive to make the switch. Unfortunately, I had already told my friend to go ahead and have them shipped to us before I read your reply. Thank you very much anyway.<br /><br />CP

 

[zzzzz]

Re: Mercuriser Exhaust Manifolds

'Scape- That's a GOOD price !!

 

[a.d.mobile]

Re: Mercuriser Exhaust Manifolds

this is not gonna work the mans are the same static height when your skier gets on the deck enging is going under static height you must read about this check flappers check the easy before spending$$$$$$$$$$ when the boat is on the trailer enging hood open look at top of manifolds and try to get a visual on the out side of baot where the top of manifolds is. put a pice of tape on the hull. go baoting watch it if water line is getting close to that even withen 8 inches that is the problem