grinding noise

[betayv]

hello guys 1987 searay with a 350 and a alpha one gen1, I been working on the boat, new gimbal bearing new bellows, new water pump on outdrive, when I start the boat with the water hose, I keep listen on a noise like tic tic tic tic like metal hitting metal, and looks like is coming from the back of the engine, any suggestion what to look.

 

[Bt Doctur]

could be the shutters in the exaust Y pipe

 

[Ostsideend]

A lot of possibilities:

1st) Use a long screw driver or something else out of metal. Press one end to different engine and drive componets and press the other end to a little above your earlap. Doing so, you should be able to localize the origin of the ticking sound a lot better.

2nd) Try to figure out the frequency of the ticking sound. Approx. count the ticks per minute.

2a) If it counts up to your engine rpm devided by 2, it could come from the valve drive (intake OR exhaust valve drive)
2b) If it is close to your engine rpm the cross joints (driveshaft) are another possibly (sometimes the cross joints are ticking idle rpm/2 as well!)
2c) If it counts up a lot slowlier than engine rpm it is comming from your Z-drive i.e. (clutch not fully open or in)

Move the steering wheel and or the trim to find out if it is changing in sound. If it changes the cross joints could be the reason.

Good luck!

 

[wrench 3]

Just a random thought, but when you were running it on the water hose, did you have the drive trimmed down far enough?

 

[NHGuy]

My engine made that exact sound when the shutters had lost the rubber on their edges.

 

[Bondo]

My engine made that exact sound when the shutters had lost the rubber on their edges.

Ayuh,.... My guess as well,.... Especially if the sound goes away, when bumpin' the throttle up off idle,...

 

[betayv]

thanks guys will remove and inspect, what are the shutters for can I eliminate them, please advice thanks

 

[NHGuy]

They are in the tops of the exhaust Y pipe. They block backwash from getting into your engine if you back down too quick or if a following wave hits too hard. Don't just remove them. Replace them with the later improved design. They are pretty important.