"90" Force 120 CFI Outboard Cylinder Head ?

I have a 90 Force 120 Model #1208F90B. The head cracked in the number 4 cylinder and wiped out the piston. I replaced the piston and rings and noticed when I measured for it that the bore was 3.375 which I read indicated a 91 model year. I search for a replacement cylinder head by Model # and found one and ordered it. It is incorrect. It is visibly different in that it has a smaller diameter chamber and the sides of the chamber are smooth where the original head has a shallow relief in each side. I'm guessing this head is for the engine with the smaller bore of 3.312. I cannot seem to find any info on when they made this head change or why. I also cant seem to find a replacement that looks like the original one that I need. Anyone have any info on this? I would give a serial number but Its no longer visible on the tag. Any other place to look for the serial#? And what exactly is CFI? It seems finding a head for this is going to be tough. Any help would be appreciated.

Thanks,
Mike

Re: "90" Force 120 CFI Outboard Cylinder Head ?

Well, if you are in a bind and don't want to or can't return the head, you can take a Dremel and relieve the top and bottom of the combustion chamber where the "wings" on the piston baffle will hit it. Compression will be a little higher but not enough that you need to buy high octane gas.

ALL the later Force 120s were 3.375 so if you want to return the head, any head from 1991 through 1999 will fit. The head gasket is the same for the 3.3125 and 3.375 bore engines. ----In fact, you could also use a head from a Chrysler 140 so it will not be as difficult as you imagine.

CFI means Cross Flow Injection. The engine is a dirt standard old school crossflow design and they used this fancy term to make it sound better to the buyer. At one time they also used the term "Swirl Charged." It was all marketing hype.

If you still can't find a head--and certainly look on the auctions, it will be much cheaper than new-- send me a private message with your email address. I will send you an email with a photo of what I have.

Re: "90" Force 120 CFI Outboard Cylinder Head ?

Thanks for the response! The boat shop I bought the head from claims it was for 91-94 engines so Im guessing that is incorrect. Your saying I can dremel the chamber to make the piston fit? I know the head gasket is the same but I figured the diffetence in piston diameter would make that a no-no. I now have 2 wrong heads so this may be an option. Are chamber depths the same on the heads? Thanks for all the answers!

Thanks,
Mike

Re: "90" Force 120 CFI Outboard Cylinder Head ?

There is at least the thickness of the head gasket clearance between the top of the piston baffle and the head. I have milled heads by .060.

The only place the piston will interfere is where the sides of the baffle would touch the head. Note that I have looked at this for some time but have never gotten around to actually relieving a 3.3125 head to clear a 3.375 piston---yet! It eventually will happen.

Re: "90" Force 120 CFI Outboard Cylinder Head ?

I decided to machine the head like you were saying. I bought a burr bit off the snap on truck and used a drill press. I made a paper template of the original head and made my marks. I got it all done and got it back together last night. I put the head on without a gasket at first and spun the motor by hand to make sure nothing was hitting and all was good. I fired it up and everything seemed to run well. My compression tester seemed to bite the dust so im picking another up tonight and I'll see what the reading says. I appreciate the info you gave me and hopefully she runs good from here on out.
Thanks again!

Re: "90" Force 120 CFI Outboard Cylinder Head ?

After being busy for a couple weekends i finall y got a compression test done got 135 on all 4. I got it out in the river today and ran it for about 4 h ours at differing rpm and she never skipped a beat. I couldnt be happier with the way it runs. Thanks again for all the help, finding heads for these for these things isnt easy.

Re: "90" Force 120 CFI Outboard Cylinder Head ?

Glad it got better!!!! Now take us fishing!!!