Replacing an OMC Cobra Water Pump Without the Tension
If you've spent any kind of time within the water with a classic boat, you understand that keeping an eye on your own omc cobra water pump is definitely the difference among a great time and also a very costly tow back to the particular dock. These sterndrives are legendary with regard to their performance, yet like any piece of vintage machinery, they have their quirks. The air conditioning is arguably one of the most important part of the whole setup because, let's face this, these engines don't handle overheating quite well.
The OMC Cobra drive was obviously a bit of a game-changer in the day, especially with how they will designed the water pump location. Unlike a lot associated with other drives where the pump is definitely buried deep within the lower device, the Cobra puts it right at the particular back from the top gearcase. This is a substantial win for DIYers because it indicates you don't necessarily have to fall the whole lower unit simply to swap out a worn-out impeller. But just mainly because it's accessible doesn't mean you can simply wing it.
Why This Little Rubber Part Matters So Much
The heart associated with the omc cobra water pump is the impeller. It's a little, circular piece associated with reinforced rubber along with several vanes. Since the engine works, this impeller moves inside a stainless steel cup, creating a vacuum that pulls cold lake or ocean water into the engine's cooling passages. Whenever it's working best, it keeps your own engine at that will perfect operating temp. When it's not, things get unattractive fast.
The problem is that rubber doesn't final forever. Even in case you don't use the boat much, the particular rubber vanes can take a "set" or become brittle over time. If you begin the engine right after it's been sitting down for any year without having exploring the pump, those brittle vanes can snap off and migrate into your engine's cooling passages. Once that occurs, you're not just taking a look at a simple pump replacement; you're looking at a game title associated with "find the silicone chunks" within your heat exchanger or thermal housing.
Over and above just age, sand and silt are the natural opponents of the water pump. If you frequently boat within shallow areas or even kick up the lot of "muddy" water, those abrasives act like sandpaper upon the rubber vanes and the metallic wear plate. This doesn't take very much to lose that tight seal required to pump water effectively.
Indications Your Pump is Giving Up the Ghost
Generally, your boat will attempt to tell a person something happens to be wrong just before the engine completely melts down. The particular most obvious sign could be the temperature measure. If you notice the hook creeping up increased than usual while you're idling, yet then it falls back down once you acquire some speed going, that's the classic symptom associated with a weak omc cobra water pump . At higher RPMs, the pump moves faster and handles to go enough water, but at reduced speeds, the worn-out vanes just can't continue.
Another thing to view for is the "tell-tale" or the amount of water coming out of the particular exhaust ports. It should be a stable, strong flow. If this looks more such as a sputter or even a weak trickle, you've got a problem. I've also noticed that the failing pump may sometimes make a faint chirping or squealing noise, though that's often drowned out by the motor itself. If a person smell something that will reminds you of burning rubber, stop the engine immediately. That's the odor of a dried out impeller friction-welding alone to the pump housing.
Obtaining Ready for that Change
Before you start unbolting things, you'll desire to make sure you possess the right parts. You can usually find a kit that includes the particular impeller, the O-rings, the gaskets, plus sometimes a fresh wear plate or housing. I usually recommend getting the full kit rather than only the impeller. In case you're going via the trouble of opening the pump, you might as well replace the gaskets as well as the wear plate too. It's cheap insurance.
Tools-wise, you don't need anything crazy. A standard socket set, some needle-nose pliers, and maybe a flat-head electric screwdriver should cover this. Something that's actually helpful is a little bit associated with marine-grade grease or even even some meal soap. You'll make use of this to lubricate the new impeller therefore it slides directly into the housing without a fight. Don't use petroleum-based oil, as it may actually degrade the particular rubber with time.
The Step-by-Step Break down
First things first, make sure the motor is off plus the battery is usually disconnected. You'll be working at the very back of the drive. Upon an OMC Cobra, there's a plastic or metal cover up on the back from the upper unit held on by three or four bolts. Once you pull individuals, you'll view the water pump housing looking right at a person. It's remarkably practical compared to other brands.
Unbolt the housing and carefully pull this away. This is where you'll view the old impeller. Sometimes it'll be stuck to the base, and you'll want those needle-nose pliers to wiggle this free. Take the good look with the old impeller. Are any vanes missing? If so, you've got in order to find where they went.
Once the outdated parts are out, clean the area thoroughly. Any bit of old seal material or salt buildup left behind can prevent an excellent close off. Put your wear plate in, then the lower gasket. Now comes the particular "fun" part: obtaining the new impeller in to the cup. This is definitely where that meal soap is available in convenient. You'll need to angle the impeller since you push it into the casing therefore the vanes flex in the correct path. On a Cobra, they should bend clockwise as you're searching at the top of the pump.
Slide the housing back onto the shaft, making sure the woodruff key (that small metal rectangle that will locks the impeller to the shaft) stays in place. This little guy is notorious with regard to falling out and concealing in the bottom of the drive. When the impeller isn't locked to the shaft, it won't spin, and you'll overheat in a few minutes. Bolt everything back down, but don't over-tighten—you don't desire to crack the housing.
Normal Mistakes to Watch Out For
The biggest error I see people create using the omc cobra water pump is dry-starting the engine on the trailer. Even five seconds of operating without water can ruin a brand-new impeller. The plastic needs the water to act as a lubricant and a coolant. If you're testing it in home, use "muffs" (flushing attachments) plus make sure the water is flowing before you convert the important thing.
Another common slip-up is definitely getting the mechanical seals out of order or upside straight down. Most kits arrive with a particular sequence. If you mess this upward, the pump might suck air rather of water, plus you'll be right back where you started. Also, maintain an eye upon the "liner" or the stainless-steel cup inside the plastic material housing. If it's scored or offers deep grooves, the newest impeller won't develop a good vacuum. If the cup looks bad, replace the whole housing.
How Often Should You Really Do This particular?
This is the million-dollar issue. Some guys vow by doing this every single year. When you're a weighty user or else you vessel in salt water, that's not really a poor idea. For your average weekend warrior within fresh water, every single two to 3 years is usually the sweet place.
Nevertheless, don't just rely on the work schedule. If you've a new "grounding" incident to sucked up a variety of sand, or if the boat sat through a particularly brutal winter without being properly winterized, you should probably check this. Winterization is massive because if water sits in the particular pump and stalls, it could crack the particular housing or the upper gearcase by itself.
Conclusions upon Maintenance
Sustaining your omc cobra water pump isn't the most glamorous part of ship ownership, but it's definitely one associated with the most gratifying in terms of peace of brain. There's a certain satisfaction that comes from knowing your cooling is fresh and that you aren't going to be "that guy" stranded in the middle of the lake with steam billowing away of the motor hatch.
It's a straightforward afternoon project that will save you numerous dollars in shop work and potentially thousands in engine repairs. Plus, it gives you a chance in order to look over the relaxation of your commute and make sure everything else looks strong. Take your period, don't force anything, as well as your OMC Cobra could keep you touring for years to come. Just remember: in the event that in doubt, alter it out. It's always preferable to substitute an impeller the year too early than a minute too late.