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triscadek

Slight vibration and engine is deeper sounding

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triscadek

So I took the boat out the last two weekends after doing all my winter maintenance. We had a slight hiccup about 5-6 weeks ago in the middle of maintenance. Not sure if it's related or not. I forgot to tighten the hose clamp on the outlet for the impeller after winterizing and it blew the hose off when I started to get up on plane. We traveled for about 30 seconds then shut it down for another no wake zone. Noticed a lot of smoke coming from the back. Thought the engine was on fire. Flew up to a dock to offload my crew since the water was 48*. They got off and I popped the hatch to find a ton of water in the bilge. Popped the hose on and fired it up to idle to cool the engine for about 30 sec. the temp came right back down. I think the engine got very warm but not detrimental since the temp gauge was likely reading steam. Got the hose back on and went back to our dock. Finished winter maintence and even replaced the water pump on the block along with everything else needed for its yearly checklist. 

Fast forward 3-4 weeks. Took out out for 30 min and never went over 25-28 mph to get a good feel. Everything seems fine. Took it out the following week and the first half was great, same as the week before. Stopped for a min to idle in gear for a min or two then got back up on plane to 25mph and about 1-2 min later started noticing a vibration from the floor, steering wheel and even in the throttle control as well as the boat sounding a little more "throaty". It doesn't sound bad but it's not what it normally sounds like to me. My wife could tell a slight difference given that she has spent a lot of time on it also. The muffler clamps are all tight and sealed. The vibration is at certain speeds and not violent or horrible but noticeable. Took the boat back and loaded up. 

The following week I took a buddy of mine for a ride that's a mechanic. To him it sounds fine, and I think it's probably okay, just not the same. He hasn't spent much time on it so he won't notice much difference in the sound from before. He could however feel the vibration.  I drove while he was feeling around and laid his hand on the V-drive and could put the vibration in the boat and the vibration coming from the v-drive in sync. We swapped drivers and I felt the same. 

Forgive me as Ive slept since last year and not up to date on the spacing etc on the shaft where it bolts to the vdrive but I remember checking it last year and it spec'd out okay given the measurements given here on the crew. Im THINKING it could be out of balance/adjustment and it needs to be adjusted. What do I use to measure again? Lol. The prop looks good as does the shaft to the eye.  Never hit any rocks or debris as our lake is very deep and I'm very mindful around the ramp and listen for any potential "whacks".  

Is there anything else that could be causing the vibration? And what do I need to do again now that I may need to adjust the spacing? What else should I look at? Any ideas on the sound of the engine? The sound mainly resonates from the back of the boat where the exhaust exits the transom and while under load. Fired it up on the trailer for about 2-3 sec and stood behind the boat and sounds fine but I don't typically fire it up like that so any inconsistencies would be hard to distinguish.

Sidenote: I did have to remove the muffler for the waterpump install and it seems to be in great shape. Could I have just shook something loose in the cooling system with a new pump actually flowing good water pressure (vs a likely 17 yr old pump) and blew it out freeing up the exhaust flow now? Kinda strange the sound and vibration came at the same time.

Also, engine noise seems to be okay while under the hatch idling and running 25mph. 

All input is appreciated and safe boating to all of you! 

-Cale

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wdr

In order for the alignment between the VD output flange and the shaft coupler to be out of the 3/1000 recommended tolerance (I beleive that was the tolerance) I imagine the engine alignment would have to of been changed somehow. Loose motor mounts and collisions being the common contributors. If the shaft coupler bolts are secured properly I don't know that you would visually notice any runout unless you separate the shaft coupler and the VD output flange and check it. You didn't hit anything so old age and it was just it's time for the mounts to move may be to blame. I would check the shaft coupler bolts first as that would cause some vibration IME, but not the new noise, then check the tolerance again. If you were messing with the muffler there might of been an internal baffle in there that came loose or out but I am not sure on the internal construction. Lastly, vibrations are hard things to track down and I have had prop strikes where I thought the submerged stick only hit the hull and not the prop. The damage was nearly invisible but was definately noticeable and had to be fixed to get rid of the vibration. Good luck.

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Bozboat

You may have overheated the exhaust hoses or mufflers or both.  If your getting good water flow through both sides you are probably ok.  Are you on the original exhaust hoses?  

Here is a photo of the inside of one of my exhaust hoses, which at the time of replacement were 12 years old.

IMG_0258.jpg

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Steve B.

I have a feeling the prop is slightly out of balance for some reason. Maybe hit a small stick or something. Get a known good prop on it for a try.

Steve B.

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Woodski

@triscadek:  Sorry to hear about the misadventure.  Just a note, and it is hard to consider given the smoke, the best thing to do when the inlet line if off after the raw water pump is to not move the boat.  The reason, the raw water pump is a positive displacement pump and only pumps or allows water past is when it is, which added quite a bit of water to your bilge as you returned to the dock.  Best thing would have been to grab the fire extinguisher and investigate the source of the smoke to minimize additional damage.  It is hard given the oh s**t moment to not return to the safety of hard ground.

From your description here are some thoughts:

1.  Vibration - most likely from an engine misfire or dead cylinder under the assumption it is related and directly after the overheat and not from some other event (prop damage, etc) and can be a variety of reasons.  I would pull all the spark plugs and check them out or simply replace them.  I would do a compression and leak down test to determine if you might have a head gasket failure due to the overheat issue, the head gasket does have composite fibers that will deteriorate at high temperatures.  Worst case would be a crack in the cylinder head or block due to elevated temperatures.  Another note here - once the engine has overheated the best way to proceed is to let is cool back down naturally or as slow as possible, adding 48 degree water could cause a stress crack to occur.  Another test is to listen to the intake and see if there is a steady hiss or the noise has some hiccups or crackles to it, which would indicate a combustion chamber issue.  Look to see if there is any water in the oil, which creates a milky looking substance on the dipstick.

2.  Noise change - two options here, an exhaust system change or internal melt or failure due to high temperature.  You may not be able to see or feel an internal muffler failure.  The second is less water running through exhaust system which does change the note in exactly the way you hear it.  Many items can lead to this so I would go over all of them.  Any plastic/rubber cooling system component is a high risk for failure, so things like plastic elbows in the exhaust manifolds and risers, collapsed or failing hoses, weakened impeller (I would change regardless), damaged impeller housing, damaged thermostat.   

Good luck tracking down the issues you noted.

Edited by Woodski

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triscadek

Thank you all for the replies. I will check everything mentioned this weekend when I go back up. 

Just to clarify, part of my winter maintence (on which the boat has only been out twice since) this year was: impeller, belt, spark plugs, fluids, water pump, thermostat, fuel filters and of course fresh oil/filter. 

The hiss of the intake was most definitely smooth and consistent. Regarding a miss,  that was my first though but the engine seems to run very smooth even at an idle. 

I have checked the oil, it is clean. 

Also, when the hose came off and I went back to the dock, I had replaced the hose so that it would flow properly. 

My biggest concern is the fact of a hot engine taking on cold water and cracking. I think I dodged a bullet for no definitive proof yet. All signs point that I should be in the clear. 

Aside from taking the prop off and to a shop I have no way to find out if it is straight. I'm not spending $550+ on a spare unless it's a necessity. I have free towing on the lake and will toss the anchor and wait if it came down to a prop getting shredded. I likely would have trouble changing it in the water anyway. 

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minnmarker
Just now, triscadek said:

Aside from taking the prop off and to a shop I have no way to find out if it is straight. I'm not spending $550+ on a spare unless it's a necessity. I have free towing on the lake and will toss the anchor and wait if it came down to a prop getting shredded. I likely would have trouble changing it in the water anyway. 

Where are you?  There's probably a crew member nearby that could loan you a spare prop and puller.

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braindamage
11 hours ago, Bozboat said:

You may have overheated the exhaust hoses or mufflers or both.  If your getting good water flow through both sides you are probably ok.  Are you on the original exhaust hoses?  

Here is a photo of the inside of one of my exhaust hoses, which at the time of replacement were 12 years old.

IMG_0258.jpg

Wow. Who thinks to take that pic?!

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triscadek

I am in Tulsa, OK. 

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wdr
On 4/6/2017 at 8:40 PM, braindamage said:

Wow. Who thinks to take that pic?!

Your proctologist! ?

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minnmarker
5 hours ago, triscadek said:

UPDATE: Went up and did some work and talked to a couple people regarding this issue. Prop shaft is still tight, double checked the shaft and prop for damage and nothing. A boat mechanic I know that works on a lot of Malibus had stated that the shafts rarely go out of balance without a bad strike. He then asked if I had a Walter V-drive, I stated yes. Then he tells me to change my spark plugs, which I did a few weeks back. He then said to check all the plug wires for fitment and pull the distributor cap. It was reallllly corroded. He said that the Walters pick up an engine Miss really bad and sent it through the boat. Replaced the distributor cap and all was well. Smooth as a whistle. ??

My wife is from Tulsa.  Sounds like they have good mechanics there too.  Nice that you got it sorted out easily!  Nothing like a full tune up.

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triscadek

Yeah, I think a new cap will be in order once a year maybe every two. 

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electricjohn

I do every other year with good luck.

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