HELP !! vibration problem

[ourb32]

Just about ready to launc our 1975 Bristol 32. Got the engine going today, runs mint ,put it into gear ,forward or reverse and I get a horrible vibration thru the entire boat.vibe gets worse as I increase RPM. none or little at low rpm. PO told me engine was remounted by some guy he wasn't found of. Could this be an engine shaft aligment problem ?? prop shaft does move slightly at the prop ,I don't know if this is normal movement thought.
How do I check the alignment ?? whats acceptable with prop shaft movement movment ?
Thanks a bunch !!
I need to have the boat out of my yard asap because I am moving .hope its something I can remedy easy

[ourb32]

forgot to mention: when boat was puchased a year ago it was on stands that were sitting on a lawn so more give than sitting on asphault driveway. thay actually sank in a few inches. when I ran the engine last year I don't remember any vibration. So could this be a problem (at least partial) with the hull changing shape because ot sat on the hard and stands were in different positions ?? just a thought after some further reading.
thanks !

[barrybrown]

If I understand what you posted, that you put it into gear while it is in your yard that is probably your problem.
The engine should only be placed into gear when the boat is in the water. You can check the alignment by unbolting the shaft coupling from the engine and use a feeler gauge to check the space between the engine and the shaft coupling all around. Should be no more than .003 variance.
Everything could be fine once the boat is in the water.

Barry

[Triton106]

You should not attempt to align the engine and propeller shaft coupling while on the hard because the potential for the boat to change shape however subtly once you launch it. Said it differently you should align the engine/prop coupling after you have launched for a while so that the shape of the hull can return to its natural position. Once aligned you should recheck the alignment after a year or so of running the engine.

[ourb32]

thank you !! I will take your advice and wait until its been in the water a week or so

[Figment]

Depending on your launch vs. rigging schedule, I'd further reccomend that you wait until the rig is up and tuned before bothering with shaft alignment.

Really though I'd venture to guess that your alignment is fine. The vibration was probably from the shaft turning (getting stuck, breaking free, getting stuck, breaking free, etc) in the bone-dry cutless bearing.

[Hesper(II)]

I realize this thread has been about inboards but I'm wondering about vibration with an outboard. I have an old (pre-1990) Tohatsu 8 hp that I've used on 3 boats so far. Now on number 4, a Morgan 24 with the cut out transom setup so it screws directly on the transom. I don't remember it having the amount of vibration I'm now experiencing but maybe that's because was mounted on an engine mount on the last 2 boats. Engine is running great. Any suggestions or experience with those rubber pads you put under the engine? I have a piece of rubber flooring the looks like it will fit. I'm concerned about slippage, though.

Thanks

[Rachel]

Actually you can align an engine while on the hard and it is quite time consuming in these CCA design boats (generally tight confines).

Although wouldn't that just be a "first" alignment, with the final alignment to be checked/made in the water?

[Rachel]

Understood! I have a friend who has an "engine pillow." I laughed at first, because it's literally a bed pillow like you would use for sleeping, only with a bit of a greyish tinge. And it has it's own shelf in a locker. For some reason it just struck me funny. Then I had occasion to lean over the engine.... suddenly that pillow was a fine quality tool!

[Ric in Richmond]

I keep the stiff foam rubber floor tiles around for the same purpose. Some in the garage soem on the boat. Just for laying on the ground or climbing around on hard pointy stuff.

[captphil416]

I aligned my boat on the hard, and then realigned after she was in the water for a week. The second alignment was very minor. I then installed a drive saver to take up engine movement on its mounts. The result a 2 cyl with the smoothness of a 4 cyl engine. Lots of luck. Phil

[captphil416]

I aligned my boat on the hard, and then realigned after she was in the water for a week. The second alignment was very minor. I then installed a drive saver to take up engine movement on its mounts. The result a 2 cyl with the smoothness of a 4 cyl engine. Lots of luck. Phil

[Triton106]

I am not sure I understand the reason for the two step alignment process being advocated here - once on the hard and once after launch. It appears no one really enjoys the alignment process so why do it twice when you can do it once? Is there a benefit of doing it on the hard that I am not seeing? I have never aligned engine on the hard before.

Being an Atomic 4 owner I don't have the luxury of engine mounts that can be adjusted by turning a nut. With Atomic 4 you actually have to lift the engine to shim it up. It's a real ordeal. I would do anything to avoid having to align my engine twice if I can help it.

[Triton106]

Got it, thanks Glenn!