'92 Force Lower Unit

[NoWorries]

Ok, my Dad has ended up with a 1992 Force 150 (Model 1508C92A / Serial 026716) that was "supposed" to be in good condition other than a broken cavitation plate and skeg. But, after removing the lower, the water pump housing has been glued/rigged back together and the lower unit is out of oil because clear silicone was used as a fix to a leaking propshaft seal. Also, when turning the prop by hand with it in gear, there is about 2 1/2 to 3" of "slop" at the tips of the prop blades.

Because of the prop slop, useless seals, broken cavitation plate, and broken skeg, it seems a new/rebuilt/used lower is in order. So, here's where the questions start.

Just what lower unit does he need? One site has listings for a type A,B,C,and D, but I can only narrow it down to a C or D. It has the water intakes in the normal location (not down on the side of the propshaft cone) and it has the rectangular anodes on each side near the top of the lower unit. Also, the skeg does not run forward all the way to the front of the nose. So, I'm assuming it's the Chrysler design, not the Merc, but I've gotten quite confused with all the differences in these drives. Being a Mercruiser man myself, the whole outboard situation is actually confusing!

When looking for a used lower, are there any other engines that share this same lower such as a Force 125 or even other Chrysler or Merc engines?

From some of the prices I've seen so far, he may be money ahead to find a good Johnson/Evinrude and throw the Force on eBay. After all, it did run good on the hose when he first bought this project boat.

Any and all help narrowing down what fits or finding another lower would be greatly appreciated. Sorry for the long post.

 

[Frank Acampora]

Re: '92 Force Lower Unit

FIRST off: Because of clearance in the drive dogs necessary for proper engagement, the "Slop" is normal. Therefore, If the gears are not rusted or damaged by lack of oil, you do not need to rebuild. If the cavitation plate is not broken too badly, I suspect that it would be worthwhile to re-seal the lower if the gears are OK.

Most seals are standard and can be found at the local bearing supply store, as can the upper drive shaft bearing if it is worn.

The water pump, however must be bought at your mercury dealer and the assembly is a bit pricey.

That engine has a dual exhaust lower; exhaust exits through both the prop and the exhaust snout. The lower has a two piece drive shaft with a splined collar joining the upper and stub at the water pump. Do not lose or damage either as they are no longer available and if they were, they would be quite expensive.

NOW: Here is where I don't have full info: Sometime in the 90s, Mercury changed the spline pattern in the driveshaft and crankshaft. If your Force still has the old spline Chrysler/Force pattern, then almost any three or four cylinder lower unit from late 1970s to early 1990s Chrysler or Force engines will bolt-up to the engine--If the drive shaft length is the same. They did come in 20 and 25 inch transom height. Gear ratio will be a little different and performance may suffer a little, but the lowers will work if this condition is met. If you buy a 2 piece drive shaft lower unit, then you can re-use your existing drive shaft and not worry about length.