Engine noise

[rgriffiths]

I have a Beta marine engine 1998, the Kabota 1505 type. 

 

Runs fine but I have this tapping/knocking noise that I can't diagnose. 

 

http://sndup.net/d2tb

 

I have had the head off, injectors checked, tappets set to 0.010 inch. All fine. 

 

I can hear the tap as the engine turns over too, before it fires up. 

 

Before I go down the route of pulling the whole thing out and stripping, or possibly replacing it., I wondered if anyone here might have some bright ideas. 

[MtB]

I bet it turns out to be something really trivial. Or you'll do a full dismantle, find nothing, rebuild it and it will be gone.

 

Or worse, still there! 

 

I'd ignore it and get on with boating if I were you.

 

 

Edited May 1, 2023 by MtB

[Alan de Enfield]

5 minutes ago, rgriffiths said:

Before I go down the route of pulling the whole thing out and stripping, or possibly replacing it., I wondered if anyone here might have some bright ideas. 

 

Before you do that, get a long screwdriver - put the handle in your ear and press the 'blade' against the engine in a variety of location, you will easily 'feel' the tapping noise when you get to its source. Gives you somewhere to start looking for the cause - could be a fuel pump 'clicking !

[Tracy D'arth]

Make sure its not a collapsed engine mounting tapping underneath onto the engine bed.

[Tony Brooks]

That sound file is not loud enough for people with declining hearing, but from what I could hear it just sounded like a diesel engine to me.

 

Make sure the bolts holding the engine mounts to the beds are tight. The big nuts on the stud stuck up through the engine feet are tight (tighten bottom up against the top, NEVER the other way round).

 

Push the engine sideways at the top, use your foot, whilst starting to see if it alters the knock because one or more engine mounts might have collapsed so metal is now bouncing on the steel beds.

[MtB]

2 minutes ago, Tracy D'arth said:

Make sure its not a collapsed engine mounting tapping underneath onto the engine bed.

 

DId you actually get to hear the noise in the sound file? 

 

The noise I think the OP means is a very fine, sharp 'click', or 'tick' noise on every revolution. 

[rgriffiths]

6 minutes ago, MtB said:

 

DId you actually get to hear the noise in the sound file? 

 

The noise I think the OP means is a very fine, sharp 'click', or 'tick' noise on every revolution. 

Thanks all.

 

Yes - that's the one. Tick, tick, tick, tick..... Definitely sounds like it is top end, and is not a mount. 

 

When I got the injectors checked, I was told there was signs of water in one of them. They said I might need to get the pump checked. Could water in a fuel pump make such a noise?

 

 

Edited May 1, 2023 by rgriffiths

[MtB]

1 minute ago, rgriffiths said:

Yes - that's the one. Tick, tick, tick, tick..... Definitely sounds like it is top end, and is not a mount. 

 

When I got the injectors checked, I was told there was signs of water in one of them. They said I might need to get the pump checked. Could water in a fuel pump make such a noise?

 

An injector would be my best guess.

 

Alan's "long screwdriver as a stethoscope" suggestion is a really good one. Listen to each injector and I bet the noise will come through louder on one. 

 

Also, try loosening each injector pipe one at a time with the engine running and see if the noise stops with one loose and not injecting. 

 

 

 

 

4 minutes ago, rgriffiths said:

Could water in a fuel pump make such a noise?

 

I doubt it, and I've a fair bit of experience with water in the fuel! 

 

[Mike Hurley]

That does sound like a tappet to me. When you had the head off did you inspect the rocker faces? If one has wear of 0.010 then you have a 0.020 gap. I certainly would not pull an engine out for that. Run the engine with the valve cover off and see if its louder.

Edited May 1, 2023 by Mike Hurley

[Tracy D'arth]

If you stand on the engine whwn it is running does the noise change?

Travel power?    Have you inspected the front crankshaft pulley?  They are known to become loose and eventually wear the end off the crank.

[rgriffiths]

45 minutes ago, Mike Hurley said:

That does sound like a tappet to me. When you had the head off did you inspect the rocker faces? If one has wear of 0.010 then you have a 0.020 gap. I certainly would not pull an engine out for that. Run the engine with the valve cover off and see if its louder.

Yes, inspected the rocker arms and all look fine. It certainly sounds like it is coming from this area.

 

The head was taken off and fully checked over by specialists (pressure test, valves etc) but it's possible they may have missed something with the rocker arms. 

 

Will do some more investigation along with Alan's long screwdriver stethoscope idea. 

41 minutes ago, Tracy D'arth said:

If you stand on the engine whwn it is running does the noise change?

I have stood on it and no change. 

Edited May 1, 2023 by rgriffiths

[Tigerr]

I used to have that engine, I think. On mine there was a travel pack generator as well at the front end. A couple of things to watch out for, based on my experience, which are a known issue with that generation of Beta 43:

The pulley setup at the front is heavy, over 25kg of iron. (newer version much, much lighter). If there's a travel pack it is also unbalanced - puts a strain on at startup which wears the front right side mount out. Makes a knock on initial startup strain. Check for any slack in the crank-stub, and also if there is any rubber crumb in the bilge below that mount. 

Related to the above, the crank stub mount for the pulleys is only a thumb-sized stub. It can wear, so that on startup it spins before the pulleys, and that makes a knocking noise, until it all gets moving. Mine did that for a month, and despite inspection, appeared solid right up till the pulley assembly simply dropped off, having threaded the stub.  Had to replace whole engine as cost to tow boat to specialists to take out, strip it down to remachine the crank was not much less than a brand new unit. 

Thanks Magnet - yours is a different engine - 35 not 43. Apologies for what appears to be an irrelevant post I have made! Good luck with the issue.

Edited May 1, 2023 by Tigerr

[magnetman]

1505 is the 35hp not the 43hp. 

 

I think they 43 uses a larger engine. 

 

Probably still has similar problems. 

 

My mum had a Beta BV1505 on her boat. engine mount nuts did occasionally come undone. 

[Bee]

I was going to suggest an engine mount knocking against the bearers but when I had that on mine it was a knock and not a tick. I would try standing on the engine or grabbing the thing and holding it firmly to see if anything changed and then loosening each injector pipe in turn as both those suggestions can find all sorts of noises. Presumably it speeds up / slows down with the engine speed? Cold engine? warm engine?  If you run it with the rocker box off that might well give you a clue, it does sound top end though. 

[Tony Brooks]

If it sounds like a valve clearance then maybe it is a small end, not that it should be a concern, they go on for years happily tapping away. Certainly not worth a strip down.

[Eeyore]

Curious, I can only find references to the valve clearance being 7 to 9 thou on that engine. Run the engine with the rocker cover off and try sliding a 3 thou feeler between each rocker and valve in turn to see if the noise reduces. 

[churchward]

On 01/05/2023 at 10:08, rgriffiths said:

I have a Beta marine engine 1998, the Kabota 1505 type. 

 

Runs fine but I have this tapping/knocking noise that I can't diagnose. 

 

http://sndup.net/d2tb

 

I have had the head off, injectors checked, tappets set to 0.010 inch. All fine. 

 

I can hear the tap as the engine turns over too, before it fires up. 

 

Before I go down the route of pulling the whole thing out and stripping, or possibly replacing it., I wondered if anyone here might have some bright ideas. 

If you can hear the noise as it turns over but has not yet fired it is possible that it is a nose from one or more of the springs on the torque/drive plate. If so it is not too much to worry about.

 

Does the noise clear when adding some RPM and return at idle or when idling in gear?

 

I just noticed you posted a audio of the sound and after listening it does not sound like what I suggested above.  It sounds like a tappet mal-adjustment to me.

23 hours ago, magnetman said:

1505 is the 35hp not the 43hp. 

 

I think they 43 uses a larger engine. 

 

Probably still has similar problems. 

 

My mum had a Beta BV1505 on her boat. engine mount nuts did occasionally come undone. 

Perhaps he meant it was new in 1998?

Edited May 2, 2023 by churchward

[bizzard]

If you take the valve cover off check the valve springs, one might have a bit of one end broken off and clicking, although still closing the valve ok. Had this a couple of times on car engines.