www.iFourWinns.com
https://www.smwebhead.com/phpBB3/

Engine Sound question.
https://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=4023		 Page 1 of 2
Author:  1NiceHarley [ Sun Jul 12, 2009 8:16 pm ]
Post subject:  Engine Sound question.
A little background first.
We bought our boat in 2007 from the original owner. He bought it new in 1994 and rarely used it but kept great care of it.
In 2007 when we bought it, we used a 3 maybe 4 times because I found a new job and between the move and having our son in December we just didn't have the time or the wife wasn't feeling up to a day on the water.
In 2008 we took it out about every weekend but didn't spend much time moving more time just floating.
Now in 2009 with our son being 18+ months we have been out several times and actually moving a lot on the lake. Blake (our son) helps watch when we are skiing, tubing, or wakeboarding and says "dada" or "moma" when one of us falls. LOL.

Now to the question.
Yesterday while out on the lake we made 4 trips across the lake. about 3 miles one way. and running about 3000 - 3300 rpm the whole time across the lake. Then on the last trip across the lake the engine got louder. I don't know how else to explain it. The exhaust just sounds louder now. Everything still runs fine, the best I can tell. I pulled my wife wakeboarding for a little while (well she tried to wakeboard, it was the first time she succeeded in getting up), everything acted fine, actually I thought it ran better. The exhaust is deeper, throatier. But I can't for the life of me figure out why. Do you think I finally got all the carbon and crap out of the motor?
This year before we took the boat out on the water I had my bellows and the gimbal bearing replaced.
Anyone have any Ideas?

Thanks In advance!
Author:  Graham R [ Mon Jul 13, 2009 9:14 am ]
Post subject:  Re: Engine Sound question.
Could be that the exhaust bellows has either split or come off at one end. Either would make the exhaust much louder.

Graham
Author:  DaleG [ Mon Jul 13, 2009 9:56 am ]
Post subject:  Re: Engine Sound question.
I am inclined to agree with Graham -- it is probably NOT just carbon cleaning out - it is probably something else -- like an exhaust bellows at the transom.

thx
Dale
Author:  1NiceHarley [ Mon Jul 13, 2009 10:53 am ]
Post subject:  Re: Engine Sound question.
Well I checked the bellows. I will double check them. Maybe I missed it.
Thanks for the responses! Any other Ideas please let me know!
Author:  1NiceHarley [ Mon Jul 13, 2009 9:00 pm ]
Post subject:  Re: Engine Sound question.
Well I double checked the Bellows. It is not the bellows.
Any other ideas?
Author:  230 Mike [ Wed Jul 15, 2009 2:34 pm ]
Post subject:  Re: Engine Sound question.
Check tightness of the hose clamps on your exhaust pipes (from the risers on down). If they were never tightened up after the first ~25 hours of use, there's a good chance they're loose.
Author:  ardy [ Thu Jul 16, 2009 5:10 am ]
Post subject:  Re: Engine Sound question.
Double check that you are pumping water for cooling, a change in note from the engine is often the first sign something is not quite right
Author:  1NiceHarley [ Thu Jul 16, 2009 2:09 pm ]
Post subject:  Re: Engine Sound question.
230 Mike wrote:
Check tightness of the hose clamps on your exhaust pipes (from the risers on down). If they were never tightened up after the first ~25 hours of use, there's a good chance they're loose.


When I get back to the house I will check that. we are on vacation now away from the boat and visiting family. Yeah. I Rather be on the boat. LOL
Does anyone have pics of how the exhaust is routed from the risers to the outdrive? I can't see up under the engine to see how it gets from the engine to the outdrive.

ardy wrote:
Double check that you are pumping water for cooling, a change in note from the engine is often the first sign something is not quite right


All the gauges where reading normal. But before we leave for the water I usually hook up the hose to the boat to make sure all is good. I will definitely do that before we go out next time.

Thanks for all the replies! Keep them coming.
Author:  Graham R [ Thu Jul 16, 2009 5:02 pm ]
Post subject:  Re: Engine Sound question.
No experience with OMC/ Cobra, but usually the exhausts on a V8 just fit onto a "Y" pipe that connects to the transom; is your drive one of the VP/ OMC joint venture types? If so, it would be just like a VP SX. Could it have had seized "flapper valves " in the exhaust like the VP V8/ early SX drives had which could have just freed or fallen off ?

Graham
Author:  1NiceHarley [ Fri Jul 17, 2009 7:32 pm ]
Post subject:  Re: Engine Sound question.
Graham R wrote:
No experience with OMC/ Cobra, but usually the exhausts on a V8 just fit onto a "Y" pipe that connects to the transom; is your drive one of the VP/ OMC joint venture types? If so, it would be just like a VP SX. Could it have had seized "flapper valves " in the exhaust like the VP V8/ early SX drives had which could have just freed or fallen off ?

Graham


Ahhh! Ours is an OMC but the motor has Volvo Penta on it also. And the parts that I had to buy for it so far, was for the Cobra/SX.
That is a good possibility. Is there a way to check them, to see if they are there and functioning?

Thanks!
Author:  Graham R [ Sat Jul 18, 2009 4:19 am ]
Post subject:  Re: Engine Sound question.
I'm afraid I've only ever heard of them, never seen them; they were discontinued on later drives (so they seem to work OK without them !).

Graham
Author:  230 Mike [ Sat Jul 18, 2009 3:05 pm ]
Post subject:  Re: Engine Sound question.
I would think you'd have to take the Y pipe off to check it, which may not be a trivial job. I agree that sounds like a likely source.
Author:  97_245_sd [ Sat Jul 18, 2009 3:08 pm ]
Post subject:  Re: Engine Sound question.
Found a discarded one (flapper) under the rear seat on our boat when we were inspecting it before we bought it. It was left there when they removed them during a recall or service action.

They are rectangular with rounded corners, about 6 inches long, 3 or 4 inches wide. There are two pivots that stick out of two sides about a quarter of the way down that let them flap in the exhaust system. They look to be a rubber coated steel, but were definitely warped and wouldn't seal in their condition.

Can't comment about their exact location in the exhaust system but our boat doesn't seem unusually loud without them. Never heard it run with them installed.
Author:  ht32bsx115 [ Sat Jul 18, 2009 7:48 pm ]
Post subject:  Re: Engine Sound question.
Howdy,

If yours is truly a 1994 model engine and drive it is most likely a Joint Venture OMC/Volvo SX drive.

The following picture is from Doug Russell Parts for a '94 5.0L
#51 is the "Exhaust Seal" If it has come loose and dropped down into the Y-pipe, it would probably cause a different sound.

You'll have to loosen the clamps (#24 & #25) so you can loosen #40 & #41 to remove #27 so you can see if one or both of the exhaust seals (flappers) dropped down into the y-pipe.

If they did, you'll have to fish them out. If you cannot "fish" them out, the engine will need to be removed so you can remove the Y-pipe to get them out. I wouldn't run it until I was sure that they didn't fall down in there.


Image




Good luck,

Rick
Author:  1NiceHarley [ Thu Jul 23, 2009 9:49 pm ]
Post subject:  Re: Engine Sound question.
Well it looks like the likely cause of the problem was the exhaust flappers. When I took the exhaust apart (Thanks ht32bsx115) I found the flappers did not move freely. The Port side one would move with a little persuasion but the the starboard side took a lot of persuasion. The port was about 3/4 the way open and the starboard one was stuck wide open. Also the starboard one looked like it was stuck close for a while because it had a bubble in the rubber on the top of it (I guess it got to hot) and it had more black soot on it than the port one.
Here are some pics. The one on the left side of the pic is the Starboard side flapper. I know it is hard to see the difference in the amount of exhaust soot on each one but the starboard one has a noticeable more black soot on it.
Image
Image
I wonder if this could be the culprit of my other problem I have been having. When I would go from idle to WOT fast the engine would stumble on itself and almost die, I had to go from idle to WOT in about a 3 count.
Thanks again guys for all the help!!!!!
Page 1 of 2 All times are UTC - 6 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/