Problem after Sea foam

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ronrobbie7

Seaman Apprentice
Joined
Sep 21, 2006
Messages
42
I have a 1989 mercruiser 5.0 w/alpha 1. I thought it would benefit from a decarb because of the age and I doubt the previous owner had done it, and I have used it on my outboard with much success. After decarbing I took it to the lake the next day. Now at WOT I have knocking sound comming from engine, but it seems to be running better than before decarb( idle and acceleration). What is the first thing I should check to fix my problem. I also put the rest of the sea foam in the tank. Thanks for any help.
 
ziggy

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Problem after Sea foam

i did me some seasnakefoam down the carb the other day. maybe i didn't know how to apply it. i did it at warm idle. near choked it to stall. i ain't been happy with the way it's runnin since. seems like something is up now. personally, i'm goin for checkin ign. electrical, then compression, the maybe my carb if i still ain't happy. we'll see. i didn't dump the rest in my fuel tank. though i thought about it. maybe i just need to add some more.....but snakefoam may not be the thing for me..........generally, i don't believe in snakeoil.......it's just a mask for a real problem.
 
R

ronrobbie7

Seaman Apprentice
Joined
Sep 21, 2006
Messages
42
Re: Problem after Sea foam

I was thinking about starting with the spark plugs first myself and then ??
 
ziggy

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Problem after Sea foam

sounds like a good place to start to me. many other places to look too though......
 
JustJason

JustJason

Vice Admiral
Joined
Aug 27, 2007
Messages
5,319
Re: Problem after Sea foam

look at the engine oil... make sure it's not to thin/smells like fuel/looks like water...etc.. if it does... change it.
2nd.... need to put a stethoscope on it to pinpoing the knokkkers...
3rd..... most sterndrives/4strokes rarely need to be decarbed
 
R

ronrobbie7

Seaman Apprentice
Joined
Sep 21, 2006
Messages
42
Re: Problem after Sea foam

Thanks I'll change oil and plugs and see if it goes away.
 
R

ronrobbie7

Seaman Apprentice
Joined
Sep 21, 2006
Messages
42
Re: Problem after Sea foam

Not sure if I mentioned that there was no knocking before the seafoam decarb.
 
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