Stuffing guts into Mercury KF-3 gear case issues

[green-thumbs]

The driveshaft gear and propshaft gears clash despite numerous trials using various shims and even no shims, KB-3 gea case is a scaled down version of gearcase used on KE-4/Mark 7, KE-7 thru KG-4 series. I am open to suggestions on how to trupble shoot p gear case issues. I was advised the goal is smooth rotation while pressing on propshat… Learning curve for setting up gear case has proven to be steeper than expected.

Thanks  Louis

 

 

 

[joecb]

Louis, we normally rely on you for solutions to these early Merc (Murky) problems !! what are we all to do now ???

Where did the gears come from? the same unit? perhaps there was an engineering change along the line ( darn engineers!) that changed the length or pitch diameter of the gear or pinion.

Patience,  don’t go for the BIG hammer yet

Joe B

[green-thumbs]

Early Mercurys are no mystery. but, KF-3 has the improved Unicast gear case which incorporates 4 bearings, 2 seals, 2 sets of thin
shims which have to be to be set up just right to achieve smooth
gear engagement. According to the manual,when a different gear,bearing,shaft or gear case some adjustment of shims may be needed to achieve smooth function,
Eeasy to understand, but, so far not so easy to do. In the meantime, a crack has developed
in rear of case estending to the
water intake slits. Joe you know
what that involves. A bare case is on hand, but, getting the tab
washer flap clear of hex head screw that secures pinion gear
to drive shaft is so far a toughie. There it sets for now,
I have a pretty good idea of what
to do, but, not so good ad toing it,
Louis

[fastjohn]

According to the parts manual, most of the parts of the KF-3 and KF-5 lower units are the same.  Should be able to substitute one for the other.

[green-thumbs]

KF-3 serues is a curious beast. Powerhead is vintage Kiekhaefer until you get to the parts that adapt it to the KF-5 tower…from there it gets complicateed. Then they changed things with each production run. Version I am working on has shear pin,others have the alternating stainshle steel and fiber discs with a difnt propeller, propeller shaft and prop nut. A lot of p new parts to replacea a shear pin. Then they moverd the water pmmp, added springy thingym neutral with a new casting and
a wire cable linked to handle.`The end result was something no owner could fix, and now deler wanted to.
So it seems ti ne anyway, Early K Models were somethhg anyone could work on and most could fix.
Louis

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