Alpha one making noise

[ojotaylor]

So I finally got the engine running great and had a blast on the water this weekend. However, on the way back to the dock, I was going 40ish mph and noticed a knocking noise. So I immediately throttled dow, turned the engine off, opened the hatch and didn't notice anything. Cranked it back up and still heard the knocking, it's only when it's in gear. I'm suspecting something from the outdrive. It's more of a deeper sounding grumble but isn't constant, which is why I called it a knock. I went back to the dock going around 15-20 mph on a plane, the sound sped up/slowed down with rpms. It's an alpha one (200/v8) connected to a mercruiser 260.

At home on the muffs I can still hear the sound but it's not as deep (when in gear). With the engine off, the prop spends freely in neutral both ways. In forward it only spins freely one way. In reverse it spends freely one way and slightly the other - can feel the gear try to stop it but I can over power it by hand.

So give me the bad news guys, haha. I'm hoping just a shift cable is out of adjustment. I had some chattering valves on the starboard side of the engine, got those quiet yesterday and also noticed a pinging/rattling noise coming from the flapper door in the exhaust pipe just after the second rubber coupling on the starboard side exhaust downpipe.

 

[pachanga27]

Just my .02 cents worth and from my experience - if this "knocking" started while you were cruising along and you had not noticed it before - I would think you have a problem in the internal gears of the outdrive that you need to check into. I had the same experience - an occasional knock in my Alpha One starboard outdrive that became a constant knock within an hour. Upon teardown, the bearings in the upper unit were in bad shape. Either way - a noise such as that - is not going to go away. Drain the lube out of the outdrive and see if you see metal in the oil. Also - take the cap off of the upper unit - (4 bolts I think) and see if the gear teeth are damaged in any way - if so - you need to teardown the outdrive and find the metal pieces as they will eventually get into places they should not.

 

[Scott Danforth]

pull the drive, with the drive off, fire up the motor (put hose into hole in transom shield). if you still have noise, its the motor. if noise went away, its drive.

inspect the u-joints, gimble, and the drive itself.

 

[ojotaylor]

I'll take the upper portion on the drive when I get home later today by taking that top cap off. It just seems odd that I had it in reverse at the dock and all was well. If I don't find anything there, I'll pull the drive today as well.

 

[ojotaylor]

So I took the top cap off, everything looked good, nothing was able to be moved around, etc. I also pulled the drain plug. There were no metal pieces in the oil and the oil was clean/green. I also thought to myself, it just sounded like its trying to go into reverse, but isn't all the way there yet-it goes into forward fine. Also I checked the movement of the prop with the engine off again, I couldn't turn it in reverse this time. I took the lower shift cable off its mount and manually pulled it with the engine running to get it to go into reverse-knocking went away. Same thing in forward. So I adjusted the upper shift cable approximately 3//16'towards the front of the boat to give it an extra push in reverse-the sound is gone now. I'm going to put it on the water tomorrow or Wednesday just to make sure things are good before the weekend. I'm wondering why it was making the sound in forward while at the lake this past weekend. Lower shift cable going bad? How much play do I have to work with when adjusting those two cables? How many of you think I'm going in the right direction with this and thinking its only the cables? I could see it making the noise I was describing if it wasn't all the way in gear, I'm just confused at the whole it was making the noise in forward while under a load...

 

[ibrw1]

check your oil, does it look milky. It just happened to a friend of mine. Cluck/knock. He got water into the upper part of the engine. Can't compress water, it bends connecting rod. Check oil, level ok and not milky, then your ok. Good luck.

 

[ojotaylor]

check your oil, does it look milky. It just happened to a friend of mine. Cluck/knock. He got water into the upper part of the engine. Can't compress water, it bends connecting rod. Check oil, level ok and not milky, then your ok. Good luck.

Oil looked good. I changed it already to make sure that wasn't it. In fact, while in neutral, everything sounded great. The engine has under 20 hours on it since the rebuild.

 

[NHGuy]

Easiest and most logical thing is to do as scott danforth said. It's the right sequence to follow too. My bet it it's the gimbal bearing or universal joints.
If the engine was just installed did you set up the engine alignment with an alignment bar? If not or if it moved you could need the gimbal or ujoints or both. Those pieces can fail with things aligned correctly too. It only takes a couple of minutes to pull the drive, so check those items first.
After you are done go back and adjust the shift cable back to spec. Best way can be found at the top of the forum in the sticky posts. See Achris's video.

 

[ojotaylor]

Easiest and most logical thing is to do as scott danforth said. It's the right sequence to follow too. My bet it it's the gimbal bearing or universal joints.
If the engine was just installed did you set up the engine alignment with an alignment bar? If not or if it moved you could need the gimbal or ujoints or both. Those pieces can fail with things aligned correctly too. It only takes a couple of minutes to pull the drive, so check those items first.
After you are done go back and adjust the shift cable back to spec. Best way can be found at the top of the forum in the sticky posts. See Achris's video.

I did align it with the bar and all was well. I pulled the drive. U-joints are good, shaft splines on coupler and drive shaft are good, surprisingly the gimble is still good BUT it looks like the front of the engine dropped down a tad. Now that I think about it, I did hit a pretty big wake right before the symptoms showed. The glassed 2x4's under the mounts do look smushed. Should I stack pieces of glassed plywood on top of each other instead?

Before everyone starts hounding me about replacing that bearing, I work on industrial equipment every day for work - the bearing is good. How it's still good, idk, but it is.

I also started the engine with the drive off for a bit, all is well with it.

 

[Scott Danforth]

The glassed 2x4's under the mounts do look smushed. Should I stack pieces of glassed plywood on top of each other instead?

need a picture. if they look smushed.... guessing the wood has past beyond wet into the mush stage.

 

[ojotaylor]

need a picture. if they look smushed.... guessing the wood has past beyond wet into the mush stage.

Are you trolling me? In my other post about fuel coming out of a carb you start talking bearings and micing everything which was irrelevant. A $25 carb rebuild kit fixed that issue. Now I say my mount material is crushed and asking for advice on what material is best to use, not if they're crushed or not - they are damaged, I don't need to post a pic to verify that. The density of a 2x4 is less than that of plywood, that's why I asked.

 

[Scott Danforth]

you took shortcuts with your motor by pulling used internals out of one motor and putting them into a used block based on your own words. I dont know of any good mechanic that would have done that.

because of that I have no doubt you will take shortcuts on properly addressing your rotten motor mounts. I stated post pictures because you obviously are looking for assistance (hence your post). we cant see what is going on. your line of stacking glassed plywood on top of each other could be taken as you want to either simply pile shims on top of your compromised motor mounts or you are looking for guidance on building the motor mounts.

However other members of this forum would also ask for photos to help assess the situation and offer direction. yet you go off on a rant.

here is some reading on hull repair http://forums.iboats.com/forum/boat...r/295740-how-to-s-and-other-great-information

 

[ojotaylor]

I did go on a rant. I asked about the proper way to build mounts. You could've posted the hull repair link earlier. I understand there are a lot of people that shouldnt be working on stuff. You don't know me, what I did while rebuilding the engine, my mechanical abilities or my situation so don't make assumptions. Had I followed your advice in the past I would have wasted A LOT of time so when you post more irrelevant comments, I'm going to get annoyed. Should I check to make sure my gas cap is on? I bet that caused the damage to my mounts.

 

[Bondo]

I did go on a rant. I asked about the proper way to build mounts.

Ayuh,..... 'n that discussion should be undertaken in the Restoration, 'n Repair forum, not here in the motors, 'n drives forum,.....

If the mount ya built is squashed, ya, build another, glassed plywood is fine,...
Donno how long the 2x wood was there, but it shoulda worked too,...

Do ya still have the alignment bar,..?? Check the alignment,....


As for yer rant,.... Scott is a valved adviser here, 'n is most usually Right on the money,.....

'n you have stated things that I also consider "Unusual" things ya did, mechanically speakin',...

We also Have to make some Assumptions, as yer right, We don't know you, nor most anybody else postin' here, especially newbies,...

We usually Assume the poster is "Mechanically" dumber than a rock, until they prove otherwise,....

Regardless of yer years of mechanical experience, yer motor rebuildin' technique is "Unusual",..... atleast in my world,....