Force lower unit identification by the cast number

[mr michael]

Hi i have been having a hard time finding parts for my 1989 force lower unit,supposed to be a 125hp,but after looking at parts catalogs im thinking its a 150hp typeA.The numbers on the unit are RW694054 and also says 89 which is probably the year.Anyone know for sure what acual size my lower unit is ?or where i may look it up?thanks in adavance:joyous:

 

[Frank Acampora]

Re: Force lower unit identification by the cast number

Right around 1989, Brunswick (Mercury) started changing lower units a bit with different water pumps and gear ratios. While they all look basically the same and until 1994 or so all were interchangeable between any three, four, and five cylinder engines, parts for each particular lower unit were not.

Physical size for all units is the same, but gear ratios can be 1.76, 2.00, or 1.95 depending upon engine and internal design. You can find out this by turning the drive shaft 2 full turns and noting how many turns the prop has gone.

If your lower unit has dual exhaust with the water intakes being six holes running up the side of the leg, then it is the newer model with a 1.95 ratio and a Mercury type water pump.

So, post a couple of good photos of the lower unit and perhaps we can identify it for you.

 

[mr michael]

Re: Force lower unit identification by the cast number

ok i can do that but its all in pieces on work bench.Lower unit wouldnt go into gear when i was in middle of lake,i finally decided to take it apart and find out how it ticked and what might have broken sinece i tried shifting the lower unit manually at the lower shift rod.Oh did i mention the case was full of water when i drained it ,Anyways come to find out the shifting fork that moves the clutch dogs back and forth was broken,both the front fork parts were snapped off.not sure why that happened ,maybe cause of the lack of lube and when it was shifting between gears it cicked out too hard and snapped the forks ?Also it bent the lower shift rod too.So im waiting for rest of seals now to put it back together.

 

[Frank Acampora]

Re: Force lower unit identification by the cast number

Oh, That's a simple fix. Brunswick never changed that particular part from the time it was Chrysler up until they changed to a Mercury type lower unit. Seals, however are specific to lower unit years/types