Replacing an OMC Cobra Water Pump Without the Stress
In case you've spent any time within the water with a classic boat, you understand that keeping a good eye on your own omc cobra water pump will be the difference among a great day and a very expensive tow back to the particular dock. These sterndrives are legendary intended for their performance, but like any item of vintage equipment, they have their particular quirks. The air conditioning is arguably probably the most important part of the whole setup since, let's face this, these engines don't handle overheating extremely well.
The OMC Cobra drive was obviously a little bit of a game-changer in the day, specifically with how these people designed the water pump location. In contrast to a lot of other drives exactly where the pump is buried deep within the lower device, the Cobra puts it right at the back of the higher gearcase. This can be a huge win for DIYers because it indicates you don't necessarily have to fall the entire lower device in order to swap out a worn-out impeller. But just since it's accessible doesn't mean you are able to just wing it.
Why This Little Rubber Part Issues So Much
The heart associated with the omc cobra water pump is the impeller. It's a small, circular piece associated with reinforced rubber with several vanes. Since the engine runs, this impeller moves inside a stainless steel cup, developing a vacuum that pulls cold river or ocean water into the engine's cooling passages. Whenever it's working right, it keeps your engine at that perfect operating temperatures. When it's not, things get unsightly fast.
The particular problem is that will rubber doesn't final forever. Even if you don't make use of the boat much, the rubber vanes can take a "set" or even become brittle as time passes. If you start the engine right after it's been sitting for a year with out checking the pump, these brittle vanes may snap off and migrate into your engine's cooling pathways. 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 rubber chunks" within your heat exchanger or thermal housing.
Past just age, fine sand and silt are usually the natural enemies of the water pump. If a person frequently boat within shallow areas or kick up the lot of "muddy" water, those abrasives become sandpaper upon the rubber vanes and the metallic wear plate. It doesn't take very much to lose that tight seal required to pump water effectively.
Indications Your Pump is definitely Giving Up the particular Ghost
Generally, your boat will try to tell you something happens to be wrong prior to the engine completely melts down. The most obvious indication could be the temperature gauge. If you notice the filling device creeping up increased than usual while you're idling, but then it falls back down as soon as you acquire some speed going, that's the classic symptom of a weak omc cobra water pump . At higher Rpm, the pump moves faster and handles to go enough water, but at low speeds, the worn-out vanes just can't maintain.
Another thing to view regarding is the "tell-tale" or the quantity 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 the problem. I've also noticed that a failing pump can sometimes create a weak chirping or squealing noise, though that's often drowned out there by the motor itself. If a person smell something that will reminds you associated with burning rubber, stop the engine immediately. That's the odor of a dried out impeller friction-welding by itself to the pump housing.
Getting Ready for that Exchange
Before you start unbolting things, you'll need to make certain you have the correct parts. You are able to usually find a package that includes the impeller, the O-rings, the gaskets, and sometimes a new wear plate or housing. I always recommend getting the full kit rather compared to only the impeller. If you're going through the trouble of opening the pump, you might simply because well replace the gaskets as well as the put on plate too. It's cheap insurance.
Tools-wise, you don't need anything crazy. A standard outlet set, some needle-nose pliers, and maybe a flat-head screwdriver should cover it. Something that's really helpful is the little bit of marine-grade grease or even even just some dish soap. You'll make use of this to use lubrication the new impeller so it slides into the housing with no a fight. Don't use petroleum-based oil, as it can actually degrade the rubber as time passes.
The Step-by-Step Break down
First things first, guarantee the motor is off plus the battery is definitely disconnected. You'll be working at the particular very back associated with the drive. Upon an OMC Cobra, there's a plastic or metal cover up on the back from the upper device held on by 3 or 4 bolts. As soon as you pull all those, you'll view the water pump housing staring right at a person. It's remarkably hassle-free compared to various other brands.
Unbolt the housing and carefully pull it away. This is usually where you'll see the old impeller. Sometimes it'll be trapped to the shaft, and you'll want those needle-nose pliers to wiggle it free. Take the good look from the old impeller. Are any vanes missing? If therefore, you've got to find where these people went.
Once the old parts are out there, clean the region thoroughly. Any little bit of old seal material or salt buildup left out may prevent a great seal. Put your new use plate in, then the lower seal. Now comes the particular "fun" part: getting the new impeller in to the cup. This will be where that dish soap is available in useful. You'll have to twist the impeller because you push this into the casing so the vanes bend within the correct direction. On a Cobra, they should bend clockwise as you're searching at the entrance from the pump.
Slide the particular housing back on to the shaft, making sure the woodruff key (that small metal rectangle that will locks the impeller to the shaft) stays in place. This little man is notorious regarding receding and concealing within the bottom of the drive. In case the impeller isn't locked to the shaft, it won't spin, and you'll overheat in mins. Bolt everything back again down, but don't over-tighten—you don't would like to crack the particular housing.
Normal Mistakes to Watch Out For
The biggest error I realize people make with the omc cobra water pump is dry-starting the particular engine on the particular trailer. Even five seconds of operating without water can ruin a brand-new impeller. The rubber needs the water to act as a lubricant and a coolant. If you're testing it in home, always use "muffs" (flushing attachments) plus make sure the particular water is moving before you change the key.
An additional common slip-up is definitely getting the gaskets out of purchase or upside down. Most kits come with a particular sequence. If a person mess this upward, the pump may suck air instead of water, and you'll be best back where a person started. Also, keep an eye on the "liner" or even the stainless-steel glass inside the plastic material housing. If it's scored or provides deep grooves, the brand new impeller won't produce a good vacuum. When the cup looks bad, replace the whole housing.
How Often Should You Really Do This particular?
This is the million-dollar issue. Some guys claim by doing this each and every year. In the event that you're a heavy user or you vessel in salt water, that's not a poor idea. For that average weekend warrior within fresh water, every single two to three years is usually the sweet place.
However, don't just rely on the calendar. If you've had a "grounding" incident where you sucked up a lot of sand, or when the boat sat via a particularly brutal wintertime without being correctly winterized, you need to probably check it. Winterization is huge because if water sits in the particular pump and stalls, it could crack the particular housing or the upper gearcase alone.
Conclusions upon Maintenance
Keeping your omc cobra water pump isn't probably the most attractive part of boat ownership, but it's definitely one associated with the most rewarding in terms of peace of thoughts. There's a certain satisfaction contained in knowing your cooling is new which you aren't likely to be "that guy" stranded in the middle of the lake along with steam billowing out there of the engine hatch.
It's a straightforward mid-day project that will save you countless dollars in shop labor and potentially thousands in engine repairs. Plus, it offers you a chance in order to look over the sleep of your travel and make sure every thing else looks solid. Take your period, don't force anything, and your OMC Cobra will keep you cruising for years to arrive. Just remember: in the event that in doubt, alter it out. It's always better to replace an impeller a year too early than the usual minute too late.