1995 Honda BF40 Noise Question

[Serverman]

Hello All,<br />I have a 1995 Honda BF40 marine motor that has a very strange noise that I am unable to locate. The motor is a electric start but manual tilt and steering. When the engine is running just a little above an idle there appears to be a metallic scraping sound coming from the region of the flywheel. I have taken the flywheel off and checked for loose magnets, scraping , bad timing belt etc but everything is alright. I have also taken the idle-bearing off and checked that for wear but it is fine also. Both the crank and cam move freely with no binding or scraping when the belt is removed. Also the noise does not appear to be originating from from the top crank bearing or vacinity. I had 3 other people listen to this noise and we are all baffled. Any ideas?<br /><br />TIA, Serverman

 

[Skinnywater]

Re: 1995 Honda BF40 Noise Question

Hello Serverman,<br />You had the timing belt and the idler for it off.<br />You said you checked the idler for wear. Was there any roughness, noise or chatter, or any roughness by feel coming from the idler?<br /><br />Also, the adjustment for the belt tighness is by spring pressure on the idler only. An over tight belt will produce a high pitched whine.

 

[Serverman]

Re: 1995 Honda BF40 Noise Question

Hello,<br /><br />I took both the idler bearing and belt off in an attempt to determine if the noise was originating from that region. The bearing had a very small amount of play but ran very smooth with no notice of binding in my hand. The noise does not appear to be a constant noise such that it is always there. It sounds like it is there maybe every 1/2 revolution or so. I know this sounds crazy but is it possible to have a very undetectable crack in the flywheel? If the upper bearing in the crankshaft was bad would it be possible to detect that with a screwdrive pressed to that area of the block and the other end to the ear to listen for such a noise? <br />BTW, I had a great time figuring out how to re-timr the engine having never done it before. Once I located all of the flywheel and cam marks it was rather easy. I tightened the idler bearing the same way it is done on a Honda car, you loosen the bolt then let the spring tension remove the slack from the belt then re-tighten. The bearing appearing to be very similar if not the same one used on a Honda car.

 

[Skinnywater]

Re: 1995 Honda BF40 Noise Question

It's highly doubtful you'd have a crack in the flywheel. Loose dowels would be more likely.<br />You adjusted the tentioner properly. Although as a warning for the water pump impeller, it's very important you rotate the engine in direction of rotation only.<br /><br />On the crankshaft timing belt pulley there is an upper and lower flange. This flange sandwiches the belt. Not tightly, but acts as a guide for the belt at this pulley. Is there any wear, dirt or any abnormalities on these flange surfaces?<br /><br />Again, I've heard many, many noises from timing belts.<br />The above flanges, pulleys and tentioner are still suspect. Another suggestion because it's very common. I've witnessed many times the painted letters/brand logos on the belt as they pass over the tentioner cause a rythmic squwak..squawk..squawk.<br />Try a little silicone spray on these components while it's running.<br /> Beware of the moving parts. <br />And beware that the silicone will be slung off making somewhat of a mess. <br />Again, beware of that rag around the moving parts. <br />If the noise changes it will be temporary. <br /><br />Good luck, keep us posted.

 

[Serverman]

Re: 1995 Honda BF40 Noise Question

Hi,<br />Thanks for the suggestion about sraying the silicon, I will try that on the weekend. I did check the two beveled timing belt washers and the cog on the crank shaft and didn't see anything abnormal. I will keep you informed if I find anything.<br /><br /> Serverman

 

[nadderdaddy]

Re: 1995 Honda BF40 Noise Question

If your idler/ tensioner pulleys have little dust caps on them check to see that they have a tiny vent hole -if not drill one this is actually a honda update also that belt should have been replaced when you took the tension off of it, if you really want to find that squeek get yourself a mechanics stethoscope, yup just like your doctor only these have a little sound dampener so you dont blow your eardrums out and be very very careful when probing for sounds around moving parts