Living With a Force Outboard 120 HP: Tips plus Tricks
If you've invested much time upon the water, you've definitely seen the force outboard 120 hp attached to the back of an older Bayliner or the classic pontoon. They will are everywhere within the used ship market, and so they generally spark quite a heated debate in the nearby boat ramp. Some guys swear they will are the easiest, most dependable workhorses ever built, while others won't touch all of them with a ten-foot pole. Honestly, the truth usually sits somewhere right in the particular middle.
I've spent my fair share of your time switching wrenches on these things, and there's a certain elegance for them. They aren't the high-tech, whisper-quiet four-strokes of nowadays, but they aren't trying to become. They represent a good era where you could in fact fix your own personal engine without needing a computer degree and three different proprietary software subscriptions.
A Little Backstory on the Force 120
To comprehend the force outboard 120 hp , you need to know where it came from. These motors actually started their lives under the particular Chrysler nameplate. Within the mid-80s, ALL OF US Marine (the folks behind Bayliner) bought Chrysler's outboard division and rebranded all of them as Force. Ultimately, Mercury Marine required the reins.
This lineage is why you'll see several parts that appear suspiciously like Mercury components and other people that look such as they belong upon a vintage piece of farm equipment. The particular 120 hp design specifically is a four-cylinder, two-stroke animal. It's a "crossflow" design, which essentially means it's old-school technology. It doesn't have the fancy immediate injection or complex valvetrains of modern motors. It's just pistons, a crankshaft, some carburetors, plus a whole lot of noise.
Why People Even now Love Them
It's easy in order to dunk on older tech, but the force outboard 120 hp has made it this really miss the reason. First away, these are incredibly gentle for that power they will put out. In the event that you compare the Force 120 to a modern 120 hp four-stroke, the weight difference is staggering. This makes all of them great for old hulls that weren't designed to have 500 pounds of engine on the particular transom.
Another big plus will be the simplicity. There is certainly very little in order to go wrong that a handy person can't figure out in their driveway. If it's not starting, it's usually one of three items: spark, fuel, or compression. You don't have sensors informing the ECU to shut everything straight down because a temperature reading is two degrees off. It's mechanical, it's raw, and it's estimated.
The Typical Headaches (and Exactly how to Fix Them)
Let's become real—owning a force outboard 120 hp isn't often sunshine and soft sailing. They have got their quirks. When you're looking at buying one or else you just inherited 1 with a task boat, there are a few things you should keep an eye upon.
The Combustion System
The most common "Force headache" is the particular ignition. These engines used a couple of various systems over the years, primarily Prestolite or Thunderbolt. If you begin losing spark on one or two cylinders, it's usually the stator or the power packs.
Here's a pro tip: if you're replacing ignition elements, try to opt for high-quality aftermarket parts from brands like CDI Electronics. They've basically engineered your flaws that the particular original factory parts had. It's the bit of a great investment, but it beats being stranded three miles offshore.
The Fuel System and Carbs
Since these are two-strokes, they depend on a regular diet of gas and oil blended together. If your force outboard 120 hp is usually idling rough or bogging down when you hit the throttle, the carburetors are almost definitely the culprit.
Modern ethanol energy may be the enemy of these old engines. It eats aside at the aged rubber lines and leaves a crud behind that's such as jelly. If a person own one of these, get used to cleaning the particular carbs every couple of seasons. It's a simple job—just several bolts and some carb cleaner—but it makes a world of difference in how the vessel performs.
The particular "Force Shake"
Don't be alarmed when the engine vibrates a bit at idle. These four-cylinder hindrances aren't exactly balanced just like a Swiss watch. They have got a bit of a "harley-davidson" vibe to them when they're sitting in neutral. Once you get all of them up on plane and the RPMs rise, they usually lessen quite nicely.
Getting the Greatest Performance
When you want your force outboard 120 hp to really push your motorboat at a decent clip, you have to pay attention to the brace. Because these motors don't have the same low-end torque as a contemporary fuel-injected motor, getting the right pitch is vital.
In case your prop is as well big, the engine will struggle to reach its "sweet spot" (usually among 4, 500 plus 5, 200 RPM). If it's as well small, you'll be over-revving and potentially damaging the internals. I've found that will a standard light weight aluminum 3-blade prop usually does the technique for many recreational setups, but it's worth experimenting if you feel like you're not getting the "oomph" you anticipated.
Also, don't unintentionally avoid the oil. Utilize a high-quality TC-W3 rated two-stroke oil and stick in order to a 50: one mix ratio. Some people try to run them leaner to save money or reduce smoke, yet these engines operate hot, and they need that lubrication in order to keep the cyl happy.
Getting Parts for a Force Outboard 120 HP
This particular is where issues get a little tricky. Since Force hasn't been in production for quite a while, you won't find parts at every regional marina. However, because so many associated with them were made, the used marketplace is huge.
Websites such as eBay are an untapped goldmine for lower models, cowlings, and trim motors. For brand spanking new "wear items" like drinking water pump impellers, gaskets, and spark plugs, Mercury dealers may often still appear them up in their legacy catalogs. Just be sure you have your own model number and serial number quick, as there were small changes made almost every yr during the 90s.
Is This Worth Keeping?
I get asked this a lot: "Should I repower the boat or keep the force outboard 120 hp running? "
The solution depends on how you use your motorboat. If you're somebody who heads out fifty miles into the particular ocean every weekend break, you most likely want something newer and even more reliable. But if you're just striking the lake for some fishing or pulling the kids on a pipe, the Force will be totally fine.
Think about it this way: a new 115 or 125 hp outboard will price you any where from $10, 000 to $15, 000. You can buy the lot of interest plugs and carb kits for that kind of cash. If the compression excellent across most four cylinders (usually looking for 120+ PSI with minimum variance), then that engine still provides plenty of living left in this.
Final Thoughts
The force outboard 120 hp is a bit of the relic, but it's a practical one. It's loud, it smokes a little, and it's got a personality that modern motors just don't have. It forces you to definitely learn a bit about how exactly your ship works, which I think makes you a better boater in the long run.
Treat this well, keep the particular fuel clean, plus don't ignore the drinking water pump, and it'll keep pushing you across the drinking water for years in order to come. It might not really be the fastest or the fanciest thing at the dock, but when it's dialed in and humming along upon a calm early morning, it's hard to beat the simpleness of an old-school two-stroke. Just keep a spare set of plugs and a wrench tool in your dried out bag, and you'll be good to go.