larryjc Posted March 18, 2017 Report Share Posted March 18, 2017 Went for a spin in my new boat the other day (well new to me). It has a Beta 38 with only 1600 hours on the clock and runs very sweetly, except below 1000 rpm when there is a horrible rattle which sounds like something knocking in sympathy with the engine rpm. Pretty sure its not internal to the engine and its almost certainly not the drive plate as it occurs in neutral. I've had a drive plate go before and it doesn't sound like one. I suspect engine mounts. I can't feel any play in them but the manual says thats its possible that the stud that goes through the rubber mount could be screwed in too far and can hit the bearer. However, I spoke to Beta and they say that the 38 mounts don't have that type of mounting. Won't be back at the boat for a fortnight so wondered if anyone else has had this problem and solved it???? Link to comment Share on other sites More sharing options...
OldGoat Posted March 18, 2017 Report Share Posted March 18, 2017 there have been similar reports on here recently. My 50HP Beta (both are Kubota engines) also rattles when cold and at tickover - as it did with my previous one. Sooo - mebe it's "a design feature" rather than a fault? Link to comment Share on other sites More sharing options...
Onewheeler Posted March 18, 2017 Report Share Posted March 18, 2017 Sounds like it might be a job for a long screwdriver held against the ear. Keep hair, gold medallions, clothes and dangly bits away from the drive belts! Link to comment Share on other sites More sharing options...
larryjc Posted March 18, 2017 Author Report Share Posted March 18, 2017 Yes - going to try the long screwdriver trick and also as the noise changes when I stand on the engine, I'll try pushing one way or the other to see if that makes a difference. Link to comment Share on other sites More sharing options...
dor Posted March 18, 2017 Report Share Posted March 18, 2017 I had a nasty rattle once. Took it in to a boatyard where the engineer kindly pointed out that a lump of steel, used as ballast in the bilge, was knocking against the engine bearer. He didn't charge me and I've learnt a lot about boats since! Link to comment Share on other sites More sharing options...
mrsmelly Posted March 18, 2017 Report Share Posted March 18, 2017 4 hours ago, larryjc said: Went for a spin in my new boat the other day (well new to me). It has a Beta 38 with only 1600 hours on the clock and runs very sweetly, except below 1000 rpm when there is a horrible rattle which sounds like something knocking in sympathy with the engine rpm. Pretty sure its not internal to the engine and its almost certainly not the drive plate as it occurs in neutral. I've had a drive plate go before and it doesn't sound like one. I suspect engine mounts. I can't feel any play in them but the manual says thats its possible that the stud that goes through the rubber mount could be screwed in too far and can hit the bearer. However, I spoke to Beta and they say that the 38 mounts don't have that type of mounting. Won't be back at the boat for a fortnight so wondered if anyone else has had this problem and solved it???? Could be the air filter box. Link to comment Share on other sites More sharing options...
Chewbacka Posted March 18, 2017 Report Share Posted March 18, 2017 55 minutes ago, mrsmelly said: Could be the air filter box. That reminds me - After I had serviced the engine (Beta 43) there was a metallic ping sound that was rpm related. The air intake horn on the air filter box was almost touching the sump oil extractor extractor pump handle and was tapping against it with engine vibration. Link to comment Share on other sites More sharing options...
Tony Brooks Posted March 18, 2017 Report Share Posted March 18, 2017 Yeh - mine fell down and touched the flywheel ring gear. Scared the hell out of me imagining all the expense it might involve. Are the bolts holding the mounts to the beds tight? Link to comment Share on other sites More sharing options...
larryjc Posted March 19, 2017 Author Report Share Posted March 19, 2017 12 hours ago, Tony Brooks said: Are the bolts holding the mounts to the beds tight? Yes they all seem tight including the lock nuts under the engine mounts which is why I was considering that the studs themselves might have been screwed in too far and were protruding below the mount and touching the bearer beams. As I said, the manual says this is a possibility yet Beta themselves say that the mounts they use on the 38 don't allow it. When I get back and having purchased a 24 mm spanner I can check it all. I don't think its the air filter box although I'll check because the sound is very 'solid' and the box is thin sheet steel. Oh and on the 38 its the opposite side to the sump pump. Link to comment Share on other sites More sharing options...
BWM Posted March 20, 2017 Report Share Posted March 20, 2017 I've also had a similar problem with the air filter rattling, just put your hand on it and press down when engine is running to check. Link to comment Share on other sites More sharing options...
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