Chatter/Rattle coming from Alpha 1 Gen II

buzzm19

Petty Officer 2nd Class
Joined
Dec 14, 2009
Messages
152
Re: Chatter/Rattle coming from Alpha 1 Gen II

Jim, I have listening to your video's and I can detect a slight intermitent noise when your at the back of the motor (in your first video) and the sound is not from your gimble bearing (I know what that sounds like). If you get a small rubber hose(like a vacumn hose) and about 2-3 feet long put one end in your ear and move the other end around you can possibly hear where the noise is the loudest. When I am looking for a noise I will use that method if you are near moving parts. Some times I can use a long screwdriver (one end against your ear and the other touching the part in question (you can test this on a car and you will see what I am talking about). Some mechanics use a stechiscope, simular as what a doctor uses for your heart but that is way too sensitive believe me I have used them (don't make a mistake and touch something too quickly-sounds like a bomb going off in your ear) I find a rubber hose works good especially looking for a small noise or a vacumn leak. In your other video's of the outdrive, to me they sound ok and to me the sound seems more at the back of the motor, you can see the outdrive shaft spinning, maybe you can see a wobble? But anyway I do hear a noise at idol inside the engine compartment at the rear of the motor. I have had outdrive noise and most of the time you don't hear them when you are running the boat. Last suggestion maybe try putting your vidio's on you tube and see if you get a response? I have watched a lot of video's on you tube with guys having problems similuar to yours. Anyway I have rambled off enough and hope this helps you. To your last question a lot of flywheels crack from fatigue in automatic cars because the flywheels are thin, Yours is thick like the clutch type cars are and I would rule out a cracked flywheel, to me seems like something is rubbing. Buz
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,344
Re: Chatter/Rattle coming from Alpha 1 Gen II

not the housing, just the steel dust cover. Some were changed to plastic ones that don't crack and produce a rattling noise at certain rpm settings
 

Jiminthekeys

Petty Officer 3rd Class
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Aug 7, 2012
Messages
83
Re: Chatter/Rattle coming from Alpha 1 Gen II

Thanks guys that has been a help. I will try the hose and maybe stethoscope method and see if I can pinpoint the location. It is sounding more and more like an engine pull is in my near future.... Ugh... Well at least that will give me a chance to clean the bilge up really good and replace the oil drain hoses and clean and repaint the motor real good.
 
Joined
Jan 19, 2014
Messages
19
Re: Chatter/Rattle coming from Alpha 1 Gen II

Have you by chance checked the condition of the exhaust flappers? If the rubber is burned off they will produce a metallic banging noise.
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
71,083
Re: Chatter/Rattle coming from Alpha 1 Gen II

Have you by chance checked the condition of the exhaust flappers? If the rubber is burned off they will produce a metallic banging noise.

Ayuh,... Only at idle,.... At 4000 rpms, they're Wide Open,...
 

DaJones

Recruit
Joined
Mar 19, 2014
Messages
4
Re: Chatter/Rattle coming from Alpha 1 Gen II

Ayuh,... Only at idle,.... At 4000 rpms, they're Wide Open,...

Has there been any resolution to the original post. I have a 1994 alpha one 5.0with the exact issue. Pulled drive, ujoints and gimbal Bering fine. I am going to try swap the prop Maybe it's cavitation
 

midcarolina

Chief Petty Officer
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Jul 16, 2013
Messages
631
Re: Chatter/Rattle coming from Alpha 1 Gen II

If I was you I would start my own thread.... you will likely get more responses.
 

Jiminthekeys

Petty Officer 3rd Class
Joined
Aug 7, 2012
Messages
83
Re: Chatter/Rattle coming from Alpha 1 Gen II

not yet. I will be trying a new prop as well and if that doesn't work I will pull the motor as soon as I get some time. Let me know if you resolve yours please!
 

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: Chatter/Rattle coming from Alpha 1 Gen II

Just out of curiosity what would cause the flywheel housing to crack?

Poor casting, or a loose mounting bolt...
That should be easy to check visually, & some tapping with a mallet...
I really doubt that it is the cause...
 

Jiminthekeys

Petty Officer 3rd Class
Joined
Aug 7, 2012
Messages
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Re: Chatter/Rattle coming from Alpha 1 Gen II

I thought I would provide an update to help other people that may experience this problem. For the most part I believe I solved the issue. What I did was adjust the timing. Unfortunately I didn't notice how much it was off (but it was slightly off). Maybe 2deg? I just used a digital timing light with an advance feature set it too 2deg advance and adjusted the distributor per factory service manual to 0degrees on the tab. (timing light was set to 2 deg advance so by using the 0 mark on the tab I think it would be a little more accurate). I also adjusted the idle down a little bit per factory spec using the digital tachometer feature on my timing light.

I took the boat out today and the noise is gone for the most part. If I run it real hard and trim up to try and get the boat past 4200 to near 4800 RPM trying hard to get it to make the sound I can but it is very slight and I would not really drive my boat in the manner that it take to now produce the slight rattle noise. So my timing seemed to be the problem for sure. Maybe what I was hearing was in fact detonation? I'm not sure but I believe it's fixed to the point where I think I can live with it! Very happy I don't have to pull the motor!

Thanks all for the suggestions and help!
 

Bondo

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Staff member
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Messages
71,083
Re: Chatter/Rattle coming from Alpha 1 Gen II

I thought I would provide an update to help other people that may experience this problem. For the most part I believe I solved the issue. What I did was adjust the timing. Unfortunately I didn't notice how much it was off (but it was slightly off). Maybe 2deg? I just used a digital timing light with an advance feature set it too 2deg advance and adjusted the distributor per factory service manual to 0degrees on the tab. (timing light was set to 2 deg advance so by using the 0 mark on the tab I think it would be a little more accurate). I also adjusted the idle down a little bit per factory spec using the digital tachometer feature on my timing light.

I took the boat out today and the noise is gone for the most part. If I run it real hard and trim up to try and get the boat past 4200 to near 4800 RPM trying hard to get it to make the sound I can but it is very slight and I would not really drive my boat in the manner that it take to now produce the slight rattle noise. So my timing seemed to be the problem for sure. Maybe what I was hearing was in fact detonation? I'm not sure but I believe it's fixed to the point where I think I can live with it! Very happy I don't have to pull the motor!

Thanks all for the suggestions and help!

Ayuh,.... Sure, Still sounds like Detonation from here,....

Run it for awhile, 'n check the spark plug color,...
That'll give ya an idea of whether the carb is runnin' Lean,....
Do a Hard run like yer talkin' of, slow down, shut-down, 'n pull the plugs for a Look at 'em,...

Both Bad timin', 'n a Lean condition are Detonation triggers,...
 

Jiminthekeys

Petty Officer 3rd Class
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Aug 7, 2012
Messages
83
Re: Chatter/Rattle coming from Alpha 1 Gen II

I'll try that. If they're on the white side then it's prob the carb making it run lean and I'll have to do a rebuild I suppose. It got fresh gas and a new water filter seperator so there should be no issues before the carb...
 

Jiminthekeys

Petty Officer 3rd Class
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Aug 7, 2012
Messages
83
Ok so I'm running lean. Plugs are new with about 3 hours on them. Pulled them after last trip and they are pretty white and clean. I checked the fuel system up to the carb. What I found was a filter in the bottom of the fuel pump (didn't know there was one). That filter was starting to dry crack around the top, was a little crushed on one side and the crevasses of the filter find had some light deposits in then around the majority of the filter. I have a new one on order and I hope that will be my fix all for the remainder of my detonation issue at 4400 RPM. I will post back when I install new filter and test with the results. Thanks all!
 

Jiminthekeys

Petty Officer 3rd Class
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Aug 7, 2012
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83
So I got the new filter installed and the detonation/pinging sound is still evident at RPM's above 4000. I can reach the full RPM range to 4500-4600 and there is not sign of RPM's fluctuating when the detonation/pinging noise starts above 4000RPM. Below is a list of what I've done so far:

New ethanol free marine fuel.
New fuel/water separator
New filter in fuel pump bowl
New fuel filter in carb fuel inlet
adjusted timing and idle to factory spec 2*ATDC
New plugs
Used mercury carb cleaner in carb

I am assuming after doing all the above that my issue is at the carburetor. Would I be right to think this? Could the factory sealed air mixture screw be out of adjustment? I will rebuild the carb myself if that is what is needed. There are no rebuild kits for the TKS carb that I could find so which parts should I replace to do a rebuild?
 

Jiminthekeys

Petty Officer 3rd Class
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Aug 7, 2012
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So I got the new filter installed and the detonation/pinging sound is still evident at RPM's above 4000. I can reach the full RPM range to 4500-4600 and there is not sign of RPM's fluctuating when the detonation/pinging noise starts above 4000RPM. Below is a list of what I've done so far:

New ethanol free marine fuel.
New fuel/water separator
New filter in fuel pump bowl
New fuel filter in carb fuel inlet
adjusted timing and idle to factory spec 2*ATDC
New plugs
Used mercury carb cleaner in carb

I am assuming after doing all the above that my issue is at the carburetor. Would I be right to think this? Could the factory sealed air mixture screw be out of adjustment? I will rebuild the carb myself if that is what is needed. There are no rebuild kits for the TKS carb that I could find so which parts should I replace to do a rebuild?
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
from watching that one video, where the tach jumps up, I would say the whole issue stems from a ventilating prop. Not a faulty prop. But something is causing the prop to slip in the water (not on the hub). Is there damage to the prop? Is there an anti-vent ring missing from the prop? Bent or missing skeg pieces.Something attached or dragging under the boat? Is there a whale tail of drive shower doing something weird to the prop's water supply?
I can get my boat to do exactly what yours is doing by trimming up too high.
I know when I'm just about to do it too, because my depth finder will stop reading accurately - bubbles where my depth sounder is mounted just slightly prelude the feeding of bubbles to the prop. It's mostly due to my hull design I suspect.
 
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Jiminthekeys

Petty Officer 3rd Class
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Aug 7, 2012
Messages
83
Howard, to be honest I probably cavitated my prop trying to produce the sound. I do not have a problem with prop slip or cavitation. Other than that video my rpms always stay steady when the sound produces itself at full speed anywhere between 4000rpm and 4600rpm. I am starting to feel defeated with this issue and may bite the bullet and see if a shop can figure it out. But the only way to hear the sound is driving the boat above 4000rpm which is the hard part to find a shop that can water test...
 

jackr800000

Cadet
Joined
Mar 17, 2014
Messages
17
If you take your flame arrestor off (better remove doghouse too so you don't have fire issues) and the sound goes away, it is just the flame arrestor vibrating and is harmless, if it really bothers you, maybe try a different flame arrestor
 

jackr800000

Cadet
Joined
Mar 17, 2014
Messages
17
Just remember how dangerous it is to run any length of time with no flame arrestor, maybe it would be good to have someone with you with fire extinguisher in hand, and put the arrestor back on as soon as possible
 
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