We make three COMPROP models to fit Force lower units type A

We make three COMPROP models to fit Force lower units type A & B:

(Type C lower units are Mercury units and fit M series COMPROPs)

F4545 4x13.5x15"

F4547 4x12.8x17"

F4549 4x12.7x19"

Which one will work the best for you? That depends upon your application. See "How to pick a prop" elsewhere in the website.

If you have a type A lower unit (1988 and prior) you have to remove the zinc anode from the lower unit first, and you will need a rear spacer- either Force part 523282 or three large washers with 1" inner diameter will do. (The prop shaft is 1" and they have to fit around the prop shaft.)

The three COMPROPs listed above and the next generation Force props (which COMPROPs are dimensionally similar to) both need the rear spacing to make up for the space of the rear plastic flair ring on your current prop (about 3/8"). You can buy the 523282, but that’ll cost $12-15; or you can find three large washers, both work equally well.

1989 and later Force engines need no spacing modifications as our props are designed to be exact replacements.

Why are there any modifications or spacing issues with these COMPROPs? Because they were designed with the second generation of the Force props as a model. The later outboards were more popular, so we designed our COMPROPs primarily for those motors, but the earlier generation outboards will fit these props very well without too much of a hassle.

What’s a zinc anode? Why do I have to remove it?

Zinc anodes are everywhere on outboards, stern drives, and inboards. Given time, galvanic corrosion will attack all the metal it can on a boat. Which metal first? Zinc. So boat builders and engine makers place sacrificial zinc parts (anodes) to be eaten up by corrosion so the other metals- aluminum, stainless steel, etc. on the boat and motor won’t be effected. When the zincs are halfway eaten, it’s time to replace them. This is only really necessary in salt or brackish water and if the boat is left in the water for weeks at a time. If you trailer your boat, never leave it in the water for weeks at a time and are always in fresh water, odds are your zinc doesn’t even show beginnings of corrosion and the zinc is unnecessary in your case.

You need to remove the zinc anode so the COMPROP will fit. Any other questions contact us by email or 800 COMPROP during office hours.