1990 7.4 strange noise

[ericcarr2000]

Heres a quick video I took of my somewhat "Grinding" noise" in my 7.4 motor. Note: Video was taken with outdrive off to alleviate anything with the gimbal bearing or the coupler. It seems to be coming from the starboard side near the bottom rear of the motor. Was thinking if it could possibly be the flappers in there making that noise. Motor runs great, starts fine, good oil pressure at around 40 PSI.
https://www.youtube.com/watch?v=t8yE...ature=youtu.be

 

[Bondo]

Heres a quick video I took of my somewhat "Grinding" noise" in my 7.4 motor. Note: Video was taken with outdrive off to alleviate anything with the gimbal bearing or the coupler. It seems to be coming from the starboard side near the bottom rear of the motor. Was thinking if it could possibly be the flappers in there making that noise. Motor runs great, starts fine, good oil pressure at around 40 PSI.
https://www.youtube.com/watch?v=t8yE...ature=youtu.be

Ok, I just listened a few more times, with the TV off, 'n the 'puter turned up high,....

Ayuh, I believe I hear some clickin', or clackin', so the shutters may well be burnt up, 'n rattlin',...

I hear mostly intake hissin', 'n exhaust lopin',...

 

[alldodge]

Heres a quick video I took of my somewhat "Grinding" noise" in my 7.4 motor. Note: Video was taken with outdrive off to alleviate anything with the gimbal bearing or the coupler. It seems to be coming from the starboard side near the bottom rear of the motor. Was thinking if it could possibly be the flappers in there making that noise. Motor runs great, starts fine, good oil pressure at around 40 PSI.
https://www.youtube.com/watch?v=t8yE...ature=youtu.be

Don't have a clue, wasn't very long to get any kind of rhythmic idea. The steering link has play in it normally and you can have some slap going on, but otherwise I don't know

 

[tpenfield]

Yea, movie was not very long at all . . . I barely got started on my popcorn

I agree with Bondo . . . some clicking (not grinding) so maybe a look down the exhaust tube with flashlight and mechanic's mirror.

FWIW - I found the remnants of my exhaust shutters in the outdrive one year. It is a good thing the check them every 2-3 years to see if they are getting burnt up, etc.

 

[ericcarr2000]

Ok thanks for the input guys, sorry for the short video but I really didn't want to run it too long because the drive was off. I'll disconnect the hose clamps and take a quick look down the exhaust tube and see what I find out.

 

[ericcarr2000]

No Title

Ok, hers what I found out. I took the risers off and took the flappers out. The flapper that was on the starboard side, the side where the noise was coming from, didn't have any of the rubber on it.

 

[thumpar]

As a test to confirm that was the noise you could put the exhaust back together and start the engine on the hose to see if the noise is gone. The flappers are there to keep seawater from rushing in so on land you would be fine without them. It most likely is the problem but by testing it you would know for sure.

 

[Bondo]

Ok, hers what I found out. I took the risers off and took the flappers out. The flapper that was on the starboard side, the side where the noise was coming from, didn't have any of the rubber on it.

Ayuh,.... I'd say ya found yer noise,....

 

[tpenfield]

Ayuh,.... I'd say ya found yer noise,....

In summary, with the rubber coating they are 'flappers' without the rubber coating they are 'clackers' . . .

 

[ericcarr2000]

Lol, never thought about that. This is my first experience with the 7.4 and bravo drive...

In summary, with the rubber coating they are 'flappers' without the rubber coating they are 'clackers' . . .

 

[ericcarr2000]

Where can I get a set if these flappers?

 

[alldodge]

In summary, with the rubber coating they are 'flappers' without the rubber coating they are 'clackers' . . .

It's all clacked up

 

[alldodge]

Where can I get a set if these flappers?

Right here at iboats, either parts or the whole thing
http://www.iboats.com/Mercruiser-Wa...9067781--session_id.646737891--view_id.268813

 

[ericcarr2000]

No Title

Everything I find doesn't look like the old ones I took out.

 

[Bondo]

Ayuh,..... I think Chris mentioned that one set or another had been updated to a drop-in replacement that avoids the pin through the pipe,.....

Just in the last week or so,....