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View Full Version : First start, loud scary engine sound...


RiverMC197
05-17-2011, 02:21 AM
Hi guys,

I have a 1997 MC Prostar 205 with an LT-1 1:1 motor and just over 300 hours. I hooked it up to a fake lake to warm it up for a pre-season oil change. It was the first time I started it since last fall. It started up, made a loud, quick, grinding/clattering noise that instantly went away, then it idled fine. I let it idle a few minutes, then gave it a little gas, and the terrible sound showed up again so I shut it off quickly. I started it another time and the sound showed up at a little higher RPM. I hope this is the engine shaking off the cobwebs, and not something major. Does anyone know what this could be? Thanks.

scharette
05-17-2011, 08:38 AM
Hi,

You cannot put it in gear while not in the water. did you use the neutral switch before giving it a little gas ?

willyt
05-17-2011, 10:25 AM
Hi guys,

I have a 1997 MC Prostar 205 with an LT-1 1:1 motor and just over 300 hours. I hooked it up to a fake lake to warm it up for a pre-season oil change. It was the first time I started it since last fall. It started up, made a loud, quick, grinding/clattering noise that instantly went away, then it idled fine. I let it idle a few minutes, then gave it a little gas, and the terrible sound showed up again so I shut it off quickly. I started it another time and the sound showed up at a little higher RPM. I hope this is the engine shaking off the cobwebs, and not something major. Does anyone know what this could be? Thanks.

I hope you meant you put it in neutral before giving it some gas... to echo what has already been said you cant put it in gear out of the water, water lubes everything that would normally be below the waterline

thatsmrmastercraft
05-17-2011, 10:36 AM
You might take a peek at the transmission fluid level and condition.

JLeuck64
05-17-2011, 10:37 AM
Sorry bud... what your describing sounds like something serious. Hopefully it is just a damper plate needing replacement.

1redTA
05-17-2011, 10:39 AM
When my LT1 car would start up cold it wouldn't have any oil in the lifters causing some slack in the rockers and tapping sound but it would go away quickly. no grinding was ever heard.

kskonn
05-17-2011, 11:13 AM
The only other thing I can think of not mentioned here is drive shaft. If you had it in gear and your splines on your drive shaft are worn or your shaft is loose I have heard that make a horrible noise like you described. If it happened at start up/ or you were not in gear then this is not the sound.

thatsmrmastercraft
05-17-2011, 11:25 AM
Is it safe to assume the isn't a belt noise?

Skir68
05-17-2011, 12:16 PM
MrMastercraft is right, check your belts, they can make some pretty strange sounds!

shunra
05-17-2011, 12:35 PM
Hi guys,

I have a 1997 MC Prostar 205 with an LT-1 1:1 motor and just over 300 hours. I hooked it up to a fake lake to warm it up for a pre-season oil change. It was the first time I started it since last fall. It started up, made a loud, quick, grinding/clattering noise that instantly went away, then it idled fine. I let it idle a few minutes, then gave it a little gas, and the terrible sound showed up again so I shut it off quickly. I started it another time and the sound showed up at a little higher RPM. I hope this is the engine shaking off the cobwebs, and not something major. Does anyone know what this could be? Thanks.

It is always hard to tell over the internet but what you are describing sounds like it could be the sound of your driveshaft and prop rotating while out of the water. I have heard them make some pretty scary sounds even though they are dead quiet when in water. Stand behind your boat while somoeone else starts it. Watch to see if the prop moves when you start it. I believe in some cases the prop can still rotate sligtly even when you are in neutral - due to viscous coupling inside the transmission. This could be why it made the noise again when you reved it up. The amount of coupling would increase when you reved the engine. Once the transmission warms up or if it is warmer outside, you might not get enough coupling inside the tranny to spin the prop.

Anyway it is an easy one to check out.

east tx skier
05-17-2011, 01:42 PM
Is your prop nut tight? A wobbly prop sounds pretty awful.

jdl xstar
05-17-2011, 02:24 PM
It should sound like this.... ;)

http://www.youtube.com/watch?v=gYhTkRxVwYQ

thatsmrmastercraft
05-17-2011, 03:16 PM
It should sound like this.... ;)

http://www.youtube.com/watch?v=gYhTkRxVwYQ

Nice..........................:cool:

nmcjr
05-17-2011, 10:30 PM
I'm sort of leaning toward the noise being from the shaft running dry too. I would eliminate that as a possibility first as mine makes a fair amount of noise when it first goes in the water too.

RiverMC197
05-18-2011, 05:31 PM
Thanks a lot guys, it did turn out to be the shaft. I had it in neutral when I revved it, but the prop still rotates a little bit when you rev it up. It was just the sound of the dry shaft/strut. False Alarm!

It still doesn't sound like the straight pip L18 though!! Love that video.