Date this Force!

[mitchbuck]

As indicated in other posts, I have a 1993 90hp Force engine that has a blown piston and needs some major work. For whats its going to cost me to do the work (in terms of time and cash), I found a potential replacement engine for not much more. The owner claims the engine is an early 1990s 90-hp Force from a bayliner. I checked out the engine and couldn't find a year or model number and was hoping some of the keen eyes on here could help me out to confirm what it is. The outboard looks clean and I am trying to figure out what year it is and whether I could use my busted engine as a parts engine if I bought it. Here are several differences from my engine:

1. The choke is on the bottom carb on this engine, while it is on the top (#1) cylinder on my engine
2. The fuel transfer port covers on this engine do not have recirculation system hoses/fittings, while my engine does
3. The fly wheel is a totally different shape/design
4. The water intake on the lower unit is inline with the prop, while on my engine it is on the upper part of the lower unit
5. This engine takes 'regular' spark plugs while mine has the flat face style
6. The ignition panel is setup different (horizontal in this case, vertical on my engine)

Here are some photos to help age this

 

[Frank Acampora]

Re: Date this Force!

Dual exhaust would put it as later than 1989-90. CFI was a term used before 1993-94 as a marketing hype. (Cross Flow Induction) Gobbledygook meaning it was an old school design cross flow engine. CFI sounds good.

So, yes, it is early 90s. Exact year will probably be determined by someone who knows the cover decals. I don't usually pay too much attention to that--exact years of my engines are not important to me.

Your engine probably has the Mercury ignition since the flywheel is different. Thus, while most parts will be swappable, only the whole ignition system would be interchangable. However, the starter is the same.

The earlier engine has the system where oil is recirculated back to the bearings rather than being burned. However, again, the transfer covers will have the cast holes for recirculating fittings and can be drilled then tapped 1/16 NPT for your fittings.

The engine does NOT take regular plugs: P.O. has replaced the originals with bent electrode plugs to try for a smoother idle. If you buy it, go bac to surface gap plugs lik in your engine.

 

[SkiDad]

Re: Date this Force!

looks like a 1990 to me from the decals.

 

[Nordin]

Re: Date this Force!

Yes it is a 1990, have had a 1990 50Hp, same decals as your and also a 1991 90Hp different decals as yours.

 

[roscoe]

Re: Date this Force!

Ignition system on your '93 should be switchbox type, the replacement motor is the older cd module.
No ignition parts are useable.

Fuel pump is also the old 2 stage pump. Your '93 should have a square Mercury fuel pump.


THe carbs are different.
The reed plates are different.
THe throttle tower and linkage is different.
The replacement motor has a choke, while your '93 has an enrichment valve that dumps extra fuel.


Yes it looks to be a '90 or '91.
A lot of changes were made from late 1991 thru the end of 1992.

 

[jerryjerry05]

Re: Date this Force!

Under the mid section cowl is a casting stamp stamp.
Also look on the starter, it might have the date on it?
Looks like a 90.

 

[okbayliner]

Re: Date this Force!

looks just like mine 1990 90 hp

 

[mitchbuck]

Re: Date this Force!

Wow thanks for the quick input everybody! So looks like not much is swappable besides the powerhead, starter, and a few random parts. Is there much difference in reliability and performance between these two motors? Will my current steering and throttle work with this motor (this could be deciding factor)?

 

[jim_b_20653]

Re: Date this Force!

Your steering and shifter cables will work. I believe your wiring harness is different. the 1990 model had individual wires that you land under the cowling. I think your 93 model had a plug you disconnect under the cowling. I don't think the powerheads will interchange either due to the shafts being different. As I recall the 90 and 93 will have different number of splines.

 

[mitchbuck]

Re: Date this Force!

Thanks. The engine comes with the wiring harness so I think I should be all set. Are parts any harder to come by for this 1990 versus my 1993 since less Merc OEM parts?

 

[Frank Acampora]

Re: Date this Force!

Nah! You just need to be creative for some parts. Electronics, fuel pump parts, pistons, water pump impellers--all the important parts are still readily available.

 

[jerryjerry05]

Re: Date this Force!

If it's running??? Just swap motors.
The transom mounts might just be the same.
If not they might just swap out and then an easy install(not really easy).

 

[mitchbuck]

Re: Date this Force!

Thanks everyone. If I end up making the switch I will be sure to update the thread on how everything went. I may end up keeping the it in the basement over the winter and spend some time cleaning, reuilbing the carbs, and replacing the impeller to minimize the chances of catastrophic failures.