|
Originally Posted by SCANDINAVIAN
(Post 4742992)
Have you replaced the IAC as BUP wrote in one of his posts? Common problem with these engines.
Check your sparkplugs and wires to make sure it fires on all cylinders. Mine has a rattling noise at low rpm´s that I know is caused by my outside flappers but not as loud as yours. Is the noise related to engine temp as it disappeared after a while when running under load?
Originally Posted by PA.WOODCHUCK
(Post 4743017)
Old school cheap stethoscope such as long screwdriver, aluminum boat pole with rubber ends removed, etc. and touch to various places on engine? other end to your ear?
No, I havent replaced the IAC yet. I have changed the sparkplugs. Took the endpipes away from the boat yesterday and tested if they leak water. But it was dry... So the only thing left that causing the water leak problem is reversion. Now I must figure out how to prevent the reversion of the water... Dry pipes ore make it difficult for the water to reverse back to the engine.. https://cimg4.ibsrv.net/gimg/www.off...db6dfe1f9.jpeg I dont really know what the knocking sound is related to. I bought a stethoscope and listened to the engine and what I could hear there was no sound in the engine. But back at the transom I heard a knocking sound... |
I have plans to make a vertical ”wall” inside the beginning of the endpipe.
Like this, but on the other side. https://cimg6.ibsrv.net/gimg/www.off...ad80263c6.jpeg Here: https://cimg9.ibsrv.net/gimg/www.off...df6b28bcf.jpeg To prevent water from reenter the exhaust. And to destroy the exhaust pulse. Thoughts? |
I have never heard of reversion in a 496mag if untouched. I´m not an engine guru but I think the cam is to mild to cause any reversion. Have you pressure tested the header itself? If not take them off and pressure test with water and check the runners for leaking water. I fried my CMI´s (its in another thread) and I´m still not sure why it happen.:(If you have water in one or several cylinders then it can be the water that is causing your idling problems.
|
I agree with the above ^^^^ I wouldn't dam off or restrict the exhaust flow, Id think you will cause yourself more issues, as stated above pressure text the headers, thats a severe angle on the tail pips dont see how the water would crawl up it.
|
Originally Posted by SCANDINAVIAN
(Post 4743167)
I have never heard of reversion in a 496mag if untouched. I´m not an engine guru but I think the cam is to mild to cause any reversion. Have you pressure tested the header itself? If not take them off and pressure test with water and check the runners for leaking water. I fried my CMI´s (its in another thread) and I´m still not sure why it happen.:(If you have water in one or several cylinders then it can be the water that is causing your idling problems.
I also pressure tested the tailpipes yesterday with no leaks. But maybe I did the pressure test wrong, I dont know. But I didnt see any leaks. I think my 496 Mag is upgraded to a HO. Whipple stage 1, headers and maybe another cam.
Originally Posted by F-2 Speedy
(Post 4743169)
I agree with the above ^^^^ I wouldn't dam off or restrict the exhaust flow, Id think you will cause yourself more issues, as stated above pressure text the headers, thats a severe angle on the tail pips dont see how the water would crawl up it.
|
| All times are GMT -5. The time now is 07:52 AM. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.