Force 9.9hp OR 15hp??????????

[Cowtip]

How can you tell the difference between these two motors if the model and serial number plate is missing? There has to be a difference in something. Do we have any Force Gurus out there? Thanks

 

[hunterope]

Re: Force 9.9hp OR 15hp??????????

Look for the #'s on the motor head. That should give you an idea of what your HP rating is. Also, Depending on the year, the SN and Model # are stamped into the lower leg or under the bottom cover up close to the powerhead. Good luck..

Oh last but not least. you can always put it in the water and open it up. If your speed is anywhere below 7.5 then chances are you have a 9 vrs's a 15.

 

[Frank Acampora]

Re: Force 9.9hp OR 15hp??????????

Or try checking the compression ratio. The 9.9 will usually be somewhere between 105 and 125 PSI and the 15 will be between 125 and 135 PSI. If you are right at 125 you are SOL but below 125 MIGHT indicate a 9.9 and over 125 would definitely indicate a 15.

 

[Cowtip]

Re: Force 9.9hp OR 15hp??????????

Thanks Guys, I did find some numbers on the jug but I can't find any info about what they mean. I also found some numbers under the flywheel. The carburator has a number on it too but that number points to a 9.9 and to a 15.
I havnt checked compression yet. One of the plug wires has an 87 on it and the other one has an 88 on it.
The part number on the bottom side of the tiller handle is a Force part number. The part number on one of the
Engine covers is also a Force part number. I'm going to assume this motor is at least an 87 Force motor.
Thanks again.

 

[roscoe]

Re: Force 9.9hp OR 15hp??????????

Thats a big assumption.
No way of knowing what year it is based on a number on a part, unless that number is the model and serial number.

95% of the parts on the 9.9 and 15 hp, from years 1984 - 1994, were interchangeable.

I doubt any parts were marked to be year specific.

Even if the part has a date of manufacture on it, it means nothing.

Parts made in 1985 were used on motor assembled in 1989.
And a replacement part made in 1994 could be put on a 1986 model motor.

You are going to have to start comparing parts on your motor, to the parts in the parts diagrams.
Look at the ignition system first, to narrow the engine year down to just a couple years.

THere were 4 different ignition systems used from 1984 thru 1994.


Start here:


http://www.dougrussell.com/partscat...id=06&coldesc=9.9 H.P. (1984-1995)&index=1459

 

[Cowtip]

Re: Force 9.9hp OR 15hp??????????

Thanks for the link! Very Helpful.