92 Force 40hp. List of problems to look out for during its life?

[wheeldriver]

I'm hoping the guru's here can provide a list of popular problems that may come up owning one of these force motors. It'd be nice to deal with a potential problem before it reveals itself. Others might be able to benefit from this also.

I recently picked up a nice looking 40hp. I've only run it on the stand so far and it runs great, idles right down very smooth. However one problem I did find that I can share is the wires coming off the trigger under the flywheel had been making contact with the flywheel. The insulation had rubbed off and exposed the wires. No damage to the wires itself just exposed. I'm guessing thats why the previous owner was selling it. It had to create some problems when at times it did make contact.

Anything the guru's here can provide will be thankful!

 

[sutor623]

Re: 92 Force 40hp. List of problems to look out for during its life?

Those motors seem really easy to work on. Merc/Mariner makes them that year. Just do basic maintenance and run her.

 

[roscoe]

Re: 92 Force 40hp. List of problems to look out for during its life?

dirty carb.
hole or tear in fuel pump diaphragm.
worn out impeller causing overheating.
air leaks in fuel lines from fuel pump to carb.
fouled sparkplugs
bad wires and connections. Ground wires on ignition plate and coils, and starter solenoid.
Cables corroding under the insulation.
Shift rod needing adjustment.

 

[jerryjerry05]

Re: 92 Force 40hp. List of problems to look out for during its life?

That old ? Most of the problems have been sorted out.
Regular maint: Plugs, impeller every year, 2 at the most.
Flushing even when using in shallow fresh water.
The hoses: Ethanol is a problem with older hoses. Find E resistant hoses and replace.
The fuel pump get a replacement diaphram and keep it ready.
The inline connectors can and will leak and start sucking air. I like OMC/ Johnson type, they seem to work best.
White lithium grease on any moving parts.

 

[wheeldriver]

Re: 92 Force 40hp. List of problems to look out for during its life?

Thanks sutor, roscoe and jerry, all good stuff. I'll be replacing the fuel pump diaphragm, impeller and the fuel lines and connectors. Do a cleaning on the carb as well.

Roscoe, in my searching through this forum on problems people are having with these force motors I've seen a number of people talk about what you said, bad wiring. One person said to replace ALL the terminals. Years ago I worked the production floor for a contract manufacture that did wiring harnesses for a variety of companys. Could be the company or person that did some (not all) of these wires was thinking quantity over quality. I'm going to look over real carefully the terminals and go from there.

 

[jerryjerry05]

Re: 92 Force 40hp. List of problems to look out for during its life?

I suggest replacing the terminals if there is a problem with no spark on a cylinder or no spark etc.
I'm not sure I'd mess with something that's not a problem???

 

[pnwboat]

Re: 92 Force 40hp. List of problems to look out for during its life?

The motors that typically have wiring or terminal issues are the older ones that use the Prestolite ignition systems. These systems use a screw terminal strip and spade lug connectors for most of the ignition wiring.

Correct me if I'm wrong but I believe your motor uses the Mercury style Thunder Bolt ignition system, which has the bullet style connectors. Only wiring problem that I've seen on these type motors is the battery charging wires from the stator. I think they're usually yellow and go over to the voltage regulator/rectifier. The bullet connectors must get really hot, because I've seen many cases where the clear protective plastic on the connectors has been discolored and in some cases actually burned. Other than making sure all the other bullet connectors are not corroded and have a sufficient amount of dielectric grease on them, they are pretty dependable.

Like Jerry says, if it ain't broke, don't fix it. Been there more times than I care to admit. Wanted to get things "just right" and ended up spending a lot more time and in some cases more money than if I had just left it alone.

 

[wheeldriver]

Re: 92 Force 40hp. List of problems to look out for during its life?

pnwboat, you are correct I do have the bullet connectors. Thanks for sharing your knowledge in that area, puts my mind at ease alittle. I'll keep an eye on those connectors and others for corrosion and heat issues. I picked up a can of contact cleaner and some dielectric grease. I'm adding a new thermostat to my list of things to address. This motor is now 20 years old and has been sitting in storage with very little use, I'd feel better knowing a new one was in there after that much time. I was thinking of rebuilding the carb on this just because of its age. But read a few stories of people doing just that and never got it to run as well as it did before so I'll pass on that job, as you say Jerry if it ain't broke don't fix it.

Sure love the simplicity of this motor, it's like my old truck. Open the hood and all you see is a motor and a carb. KISS technology at it's finest.

 

[pnwboat]

Re: 92 Force 40hp. List of problems to look out for during its life?

Yes they are pretty simple motors, and things do break on them but they are relatively easy to fix. Two other items you might want Keep in the back of your mind is the fuel pump diaphragm and the water pump impeller. Both are made of rubber and do deteriorate with age and are inexpensive. Those are two items that I change on a regular basis every two years. If either one fails, it's a show stopper. Not saying you need to change them but that's just what I do. So far...knock on wood, I've never been stranded due to either one failing.