FD-16 Whines????

[Bunky]

We have an old FD-16 18hp and it seems to run ok but it has a whine in it when it's running... Is this common or is this something I should check into...

 

[Chinewalker]

Re: FD-16 Whines????

Hi Bunky,<br /> More than likely that is a gear whine from the lower unit. The pinion gear sits in a bronze bearing and if water has ever been an issue inside the unit, that bearing will wear in a hurry, allowing the gear to get off-center in it's alignment with the propshaft gears. If it were mine, I'd split the gearcase and take a look... <br />- Scott

 

[Joe Reeves]

Re: FD-16 Whines????

In addition to ChineWalker's reply which I agree with totally, I would add.....<br /><br />Even when all is well, on rare occasions, either the wrong grease (too heavy), or too much grease might be applied to the top driveshaft splines in conjunction with the top driveshaft O Ring.<br /><br />This situation creates a hydraulic pressure, forcing the driveshaft downwards which results in a whine such as you describe.<br /><br />If this is the case, the cure is to simply remove the grease from ONE "V" CHANNEL of the top driveshaft splines (One Spline Only). This allows the excess grease/hydraulic pressure to escape via that one spline, and in that process lubricate that spline to avoid rusting.<br /><br />This has, in the past, been a common problem with some of the higher horsepower engines (28, 33, 40) but has been known to occur in the smaller hp range.

 

[Bunky]

Re: FD-16 Whines????

Joe when you are talking about the top spline "V" I assume that your talking in the lower unit not up by the powerhead??

 

[Droll]

Re: FD-16 Whines????

I assume that your talking in the lower unit not up by the powerhead

Joe´s reply was <br />top driveshaft splines in conjunction with the TOP driveshaft O Ring<br />Also splines were the driveshaft meets the crankchaft , right Joe ? . <br /><br />The lower part of the drive shaft are below the waterpump , all covered in the lowerunits oil .

 

[R.Johnson]

Re: FD-16 Whines????

Another thing that can cause a whine is a bent gearcase or exhaust housing. When taking one of these gearcases apart for serviceing, it is not uncommon to find wear at the top bushing in the case. This can vary from a smooth groove to rough gouging on the driveshaft. This is most always caused by a bent case. To check for this condition, with the gearcase apart, you can put the case upside down on a drill press table, or a surface plate, and check it for parallel with a dial indicator. The tolerance on the 18 HP is .025 for the gearcase, and .005 for the exhaust housing. You won't find these figures in the service manual. The figures I have came from a chart I picked up at OMC service school in the 60's. I have found some cases, and housings bent over twice that amount.

 

[Joe Reeves]

Re: FD-16 Whines????

Droll.... Yep, I was speaking of the TOP driveshaft spline. Thought I specified that pretty clearly.<br /><br />Bunky.... Get those glasses changed (grin).