1988 Force 125, will a thru hub prop work on a non thru hub engine

[dz1]

Well, I have a 1988 Force 125hp outboard. The selection seems better for a thru hub exhaust prop than a non thru hub exhaust prop. I currently have a Michigan prop # 073007 stainless steel prop which seems to be a thru hub exhaust prop? I would like to try and get a 13p prop as this one is a 15p prop. I have a 1988 Maxum 19.5 foot boat that tends to run near its capacity. Tachometer is broken, I have a new one coming, but the way it is now it sounds like its stressed a bit and I am using a ton of fuel and thats after getting up on plane properly trimmed and then throttling down a bit.

 

[Frank Acampora]

Re: 1988 Force 125, will a thru hub prop work on a non thru hub engine



YES!. AND---There is no difference in performance. However, you must be certain you are buying a small 4 inch diameter (hub) prop, like for a small gearcase Mercury 90. Bigger Mercury engine props have a larger hub diameter and will not fit the Force. ALSO: Some props may need some small modifications to fit correctly. For example: The Ballistic in the first photo needed the anode removed and a special thrust collar installed on the prop shaft instead of the stock thrust washer.

As far as fuel, expect to use about 12 1/2 gallons per hour at full throttle. The boat above uses about 15 gallons of fuel an hour at WOT at 5900 RPM at 60 MPH. Old Force engines are old technology and not very fuel efficient compared to more modern engines.

I think 13 pitch will be too low for that engine/hull combination and fuel mileage may get even worse. Really, do not change props without first installing some type of tachometer. You need to know where you are before you can get where you are going.

 

[steelespike]

Re: 1988 Force 125, will a thru hub prop work on a non thru hub engine

While I think the answer to your question is yes there may be some qualification to that yes.
Frank should be along with any details about this.
While this is clearly a prop question it is also a Force question you might get more responce over in the
Chrysler Force section. Tell them I sent you.
Franks got you covered I'm a day late and a dollar short.

 

[dz1]

Re: 1988 Force 125, will a thru hub prop work on a non thru hub engine

Frank,
Thanks for the heads up. I just got my tach. I will install it over the coming week so the next time out I can get a better reading. how do you feel about trim tabs?

 

[Frank Acampora]

Re: 1988 Force 125, will a thru hub prop work on a non thru hub engine

Useful on some hulls, useless on others. See where you are before jumping to confusions.

 

[Starcraft1709owner]

Re: 1988 Force 125, will a thru hub prop work on a non thru hub engine

I have a 1997 Force 120 hp with a Mercury lower unit and standard aluminum prop, that I just damaged this weekend. I am currently cranking out 4800-5000 rpms (prior to damaged prop) with a top speed of 43-44 mph on a 17' fiberglass Starcraft. Planing is quick and easy and cruising speed is about 25 mph at 3800 rpms. What would be a good replacement prop to drop a few rpms at cruising speed to use less fuel, if possible?