Engine Noise - Maxum Boat Owners Club

brineair · 08-08-2016, 05:24 PM

Well this year has been pretty rough so far as far as repairs go. Seems that every trip leads to another repair.

https://m.youtube.com/watch?v=4wdD9HMSIGg

If you follow the link above to my youtube page it will show you the sound that my engine is now making while we are running. And that is running anywhere from half throttle to full throttle.

Also my RMPs wouldn't go over 2500 and it felt like we were getting nowhere. Then the engine would start to slowly lose RPMs all together and begin to die out.

Now to negate the possibility of it being a problem in the engine, I put the boat in neutral and revved the engine. The RPMs went straight up to 4000-4500 like they normally would at around full throttle. Everything sounded great. No metal chattering or clanking sounds like you can hear in the video. So this has me wondering if it is in the outdrive.

On a side note I had a mechanic friend look at it quickly while we were on the water. He said he felt a little resistance while spinning the prop.

I am going to take it in to have it serviced, but was wondering if anyone had ever heard this sound before.

Thanks again for any and all help!

mmwjr · 08-08-2016, 11:08 PM

The video is rather short to get a good listen. The fact that the engine will rev up in neutral means nothing as it has no load. However since there was no noise doing this suggests it may be the drive. What drive do you have? Have you checked the gear lube and oil levels?

Any smells?

brineair · 08-08-2016, 11:35 PM

Quote:

Originally Posted by mmwjr

The video is rather short to get a good listen. The fact that the engine will rev up in neutral means nothing as it has no load. However since there was no noise doing this suggests it may be the drive. What drive do you have? Have you checked the gear lube and oil levels?

Any smells?

I have a Bravo III. I haven't checked the gear lube or oil levels in the outdrive. No smells that I noticed. However I will be running it out of the water with the muffs on here soon. I will pay attention for a smell.

jamanati · 08-08-2016, 11:55 PM

Perhaps bad U-joint on the drive.

brineair · 08-09-2016, 02:02 AM

Quote:

Originally Posted by jamanati

Perhaps bad U-joint on the drive.

I know from previous posts that I've made regarding my bellow leaking on my outdrive, that excess water over time can rust the u-joint.

How do you suppose that noise is coming from the u-joint?

Thanks for the reply.

mmwjr · 08-09-2016, 04:08 AM

Since you said the noise goes away in neutral it's not the u-joints as they and the input drive shaft are turning all the time. The clutch is located in the top of the drive and the issue is either there or the lower unit.

Does it make the noise in reverse?

When out of the water drain a little gear lube to look for metal in the lube and on the drain plug magnet.

brineair · 08-09-2016, 01:33 PM

Quote:

Originally Posted by mmwjr

Since you said the noise goes away in neutral it's not the u-joints as they and the input drive shaft are turning all the time. The clutch is located in the top of the drive and the issue is either there or the lower unit.

Does it make the noise in reverse?

When out of the water drain a little gear lube to look for metal in the lube and on the drain plug magnet.

Mike,

I will see if it make the noise in reverse. Unfortunately we are supposed to have storms here in Ohio till the weekend. I will keep you updated and look for the other things you mentioned. Thanks again!

brineair · 08-14-2016, 04:56 PM

So I was able to get it out on the water. We didn't hear it at all in reverse but definitely heard it again driving forward.

It didn't start making noise at first and we had the throttle all the way down today. We can it full speed for about 5-10 minutes. We heard little clanking noises that were very faint but noticeable. Then after running it full throttle for about that 5-10 minutes we idled for about a minute to look around in the engine compartment. Couldn't see anything i g out of the ordinary so we took off again at full speed. Finally it started making that noise again that is in the video I posted above.

Once we heard that we tried it in reverse and didn't hear it. We also tried revving the engine all the way to 4000rpms in neutral. That also didn't make any sounds. Lastly when we got it out of the water and put the muffs on it it still made no noise even with the prop turning at about 3500 rpm's.

The only thing I haven't done yet is check for metal in the lube and drain plug magnet.

Thank again for any replies!

mmwjr · 08-14-2016, 05:17 PM

No noise in neutral or reverse but only in forward says its a drive issue related to the forward gear and cone clutch. $$$

brineair · 08-19-2016, 02:15 PM

Quote:

Originally Posted by mmwjr

No noise in neutral or reverse but only in forward says its a drive issue related to the forward gear and cone clutch. $$$

Thanks for the info. What would cause that? Only thing I can think of is right before I started hearing the noise I did get into some pretty shallow water one day and felt the prop/outdrive brush the bottom of the river. Most likely it was dirt/sand that it hit. But who knows what was actually down there.

As far as the $$$ issue. How much are you thinking? Would I need a whole new outdrive? Or am I just replacing the forward gear and cone clutch? Luckily I have a guy that is willing to help me out and he knows what he is doing as well. However he is very busy and hasn't had much time to look into it yet.

mmwjr · 08-19-2016, 02:58 PM

A new B3 is $4000 - $5000, rebuilding will be about half the cost if only isolated to the forward gear and clutch.

Why it happened??? Things wear out or kissing the bottom you hit something hard but the props would be damaged as well.

brineair · 08-24-2016, 09:04 PM

Quote:

Originally Posted by mmwjr

A new B3 is $4000 - $5000, rebuilding will be about half the cost if only isolated to the forward gear and clutch.

Why it happened??? Things wear out or kissing the bottom you hit something hard but the props would be damaged as well.

So, looked at the the u-joint and it seemed to be fine as did the yoke. When looking at all of this I mentioned to the guy looking at the boat that you thought it may be the cone clutch/ forward gear. We didn't get to looking into that but he later told me he discussed this with a mechanic at the local sea-ray dealer and if I remember right he told me that it wouldn't even go in gear if that was the problem. Something along those lines. So he ruled that out. However since we didn't open anything up that would show damage there we can't be for sure in my opinion.

The only thing we noticed that seemed odd was when we turned the prop you could hear a small very faint metal grinding against metal sound every time the prop did a full single rotation. I believe this was when we turned the prop in both forward and reverse.

Going to take the prop off here soon. Didn't have the right size socket for the prop lock key.

Again I appreciate all of you help! Any other ideas or suggestions are always welcome!

mmwjr · 08-24-2016, 10:36 PM

Did he drain any gear lube to look for metal fillings? Also the drain plug has a magnet on it so any filling would be stuck to it.

If truly only an issue in forward it has to be centered around the cone clutch and forward gear as all other parts are commonly used in reverse.

speedysprocket · 08-25-2016, 01:26 AM

Any pair of gears could have worn in the forward direction and be making noise and when you go in reverse, the back side of those teeth still have the factory finish and are quiet.

Sent from my iPhone using Tapatalk

mmwjr · 08-25-2016, 02:52 AM

Quote:

Originally Posted by speedysprocket

Any pair of gears could have worn in the forward direction and be making noise and when you go in reverse, the back side of those teeth still have the factory finish and are quiet.

Sent from my iPhone using Tapatalk

While possible based on the OPs initial post with video I think this is not the case.

brineair · 08-31-2016, 01:56 AM

Mike and Speedy, thanks for responding to the thread!

To Mike's question. I ran the boat on the muffs today for about 15 minutes to warm the engine. After that I did finally pull the oil plug and fortunately we found no metal fragments. We looked on the magnet on the plug as well as in the oil that we drained out. We didn't drain much but the gentlemen I am working with said that was enough to tell if there were metal fragments or not.

I have another guy coming out soon to ride with me to hear the noise then he will probably end up pulling the outdrive apart.

On a side note...my engine oil is very old. I forgot to change it out last season and I had just assumed the dealer I bought it from would have changed it before I bought it. Well they didn't, so my oil is at least a few seasons old.

mmwjr · 08-31-2016, 02:30 AM

Yep that should be enough to tell if metal is in the lube. It will interesting on the final outcome here as if there is a drive issue I would expect some metal at least on the drain plug magnet. Yet all other components are turning even in neutral, however the load on them in forward is higher.

Keep us posted.

brineair · 08-31-2016, 03:24 PM

Will do.

brineair · 10-18-2016, 04:50 PM

So final verdict was a blown head gasket and then due to it being like that for a while the head had to be reworked a bit. All is now good to go. So the knocking noise was coming from the gasket not having a proper seal.

mmwjr · 10-18-2016, 04:55 PM

Glad you got it resolved, did you pull the other head to check it for flatness while the engine was apart?