View Full Version : Engine noise
07-07-2006, 08:08 PM
"Hi, new member great website, I have a mercruiser GM 4-cylinder 3.0L 40 hours on new engine, Iím hearing a chirping kind of like a cricket noise not really a squealing, this noise only starts up at 1800 rpm and above anything under this the noise will stop and can be run with out noise for hours, checked out the alternator bearing and belt, greased the gimbel bearing and coupler, boat runs great other than this noise that comes up, 40 psi oil pressure running about 75 Ė80 degrees but soon as you crank her up sure enough the noise is back when run at 1800 and below it will stop. Boat out of water with muffs I canít get noise even taking up to 1800-rpm hate to top 2000 rpm out of water. I worry if I take it in to the shop then they will thrash the hell out of it to try and get the noise up, I wonder if anybody else has had this problem ..Thanks Ray"
07-07-2006, 08:34 PM
"Belt squeal? Toss your spare belt(s) on it and see if that might not help. Or, shoot some belt-ease on the belts when it's in mid chirp.
Thats a cheap and easy troubleshoot."
07-07-2006, 09:38 PM
"Iíve tried the belt-ease, only one Belt, I will replace belt. If the engine was not lined up with the gimbal bearing could this make such a noise? ÖÖThank you"
07-08-2006, 09:18 AM
"Sorry about that....I shot from the hip and missed that on your post.
If you only tried the belt ease, then you might want to slap your spare on there for grins. I had some screaming belt issues with one of mine and it was fairly new. No amount of juice would quiet it down so I replaced it.
Of course, I have no idea what it sounds like so I'm guessing.
If you cannot generate the noise oh the hose (and out of gear) then perhaps I am barking up the wrong tree and it may be tranny related. Sounds like you've already figured that part out too.
Have someone drive the boat on a calm day while you stick your head in the engine compartment. That ought to get you pointed in the right direction. When the squeak starts have them vary the rpm just a tad. As it comes and goes it may be easier to pinpoint.
Dunno. thats a stumper."
07-08-2006, 07:45 PM
"Pull off the belt and run it to the point of the noise. No noise it's the belt,alternator,water pump. Do not run it very long without the belt. If it makes the noise when it's cold this is the time to remove the belt. Try not removing the belt with a hot engine. If the niose is still there move on. Did the drive slide on and off easy or did you have a problem? If it was hard check the alignment of the engine. Did you check for a vacuum leak? Hi- pitched squeal sometimes. Exhuast leak. Muffler bearing? Heck I don't know. That is a hard thing without hearing it. Just a few ideas. Hope one helps you out."
07-13-2006, 12:59 PM
"I'm shootin' from the hip also. Not real familiar with your motor, but I've had instances when a rocker arm would "squeak". Another item that can squeak under load is the fuel pump push rod. Of course if yours is 'lectric, that's out. Let us know what you find. I'm assuming it only does it while in gear. Right?
07-16-2006, 08:19 PM
"Yes the noise does seem to come from the fuel pump area in the block this did cross my mind, Iím going to ask a mechanic to listen and see what he thinks, then I will take the fuel pump off and look at the condition of the arm, I did replace the belt made no difference, I did take it up to 2000 revs and got the noise up out of the water so now I can take it to a independent mechanic and see what he might think.
It will make the noise in or out of gear, the noise only starts a little above 40 psi when engine is below 1800 revs it will drop just below 40 psi then noise stops so engine oil pressure is a factor, I will let you guys know what happens, I hope to take it in this next week thanks"
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