How to Read an M.e.d.s. Report on a Boat Engine

Outboards with issues can be costly to repair, then hire an engine surveyor before you buy a used gunkhole.

Last time I looked, neither Yamaha nor Honda nor Mercury nor Suzuki nor whatever other builder of outboard motors was giving away engines. And qualified mechanics weren't performing repairs for chump alter either, so a serious engine trouble could cost you a considerable pile of greenbacks. If you already ain an outboard gunkhole with propulsion problems, expert luck—simply perchance repair isn't the answer: It could be time to sell your lame duck and move into another boat that's bigger, newer, faster or more efficient. Let someone else worry virtually those old motors. Just beware of the guy who'south doing the same thing: dumping a vessel with bum outboards on an unsuspecting sap. Don't be that sap. Before handing over a Halliburton total of Franklins or a cashier's check with the numbers running off the edge, call an engine surveyor.

Nosotros all know that it's important to have whatever boat surveyed before sealing the final deal, merely most yacht surveyors aren't engine surveyors. Sure, they might pop the cowling and await things over, check for oil leaks, croaky spark plug leads, excessive corrosion and other problems in plain sight. Merely they typically don't take anything apart, other than open the oil drain on the lower unit and run across what drips out. I'm told that in the "erstwhile days," whenever that was, surveyors would do pinch checks on a motor or motors equally part of the survey. I don't see that today, although some surveyors offer such checks for an actress fee.

A pinch test, by the way, measures how much each piston is compressing the air in the cylinder, using a elementary approximate threaded into the spark plug port. Compression-testing a common cold engine won't give accurate results, so the engine has to be warmed up to operating temperature before pulling the plugs. Comparing the test results with the factory specs for the engine as new suggests the general state of the cylinders, pistons and piston rings; as the engine wears, the compression gradually decreases. Depending on which expert y'all ask, the ideal is for all the cylinders to read within 10 or possibly even 15 pct of each other. Greater variation in one or more than readings indicates problems specific to a particular cylinder or set of cylinders, maybe a broken piston ring, or bad valves, a diddled gasket, etc. If at that place'southward a problem, an engine surveyor can run further tests using equipment and knowledge a typical yacht surveyor won't have.

Merely don't go running out to buy a compression test kit quite yet—there's more to an outboard motor than compression, and there's an easier style to diagnose the overall condition of a motor at present that we're in the 21st century. Well-nigh outboard motors (and inboards and diesels, too) are electronic, and have been since the 1990s: electronic fuel injection, electronic ignition, electronics all over the place, with sensors that feed data on the state of each arrangement to anyone with the ability to access it. And that "anyone" is typically a mechanic or engine surveyor with a laptop and the appropriate diagnostic software—maybe someone like Capt. John Banister of Palm Embankment Gardens, Florida, or Robert T. Scanlan from Nahant, Massachusetts, ii engine surveyors with years of feel and a boatload of certifications and training. Both men are too qualified marine surveyors and tin can do an overall survey of a vessel and her engines.

A simple compression check won't e'er reveal big issues. To truly know what you're getting, hire a surveyor to conduct a diagnostic exam.

When I asked Banister and Scanlan what they look for when surveying an outboard, both said the most important thing is to see detailed maintenance records: What was done, when it was washed and who did it. Without records to prove the engine has been properly maintained, the safest bet is to assume information technology hasn't. Here'due south where electronic diagnostics come into play. Outboard dealers and their mechanics have proprietary software for analyzing engines, tech that's not available to independent mechanics.

In that location are, however, other programs anybody can buy. One is the Marine Engine Diagnostic System (M.E.D.Southward.) from CDI Electronics in Huntsville, Alabama. A technician I spoke with at CDI said that One thousand.Eastward.D.South. was designed specifically for the mechanic who doesn't have admission to a dealer'due south software. M.East.D.Due south. supports almost every outboard and gasoline inboard engine manufactured since 2000, and some that are even older; more models are being added continuously, said the tech. (There are similar programs that tin diagnose both gas and diesel engines; Jaltest is one, TEXA another.)

Co-ordinate to Banister, the only thing Thousand.E.D.S. won't let him do is alter the engine's mill-ready parameters—the timing, for case. But information technology volition do all the diagnostics he needs for an engine survey. (Notation that Banister is also a factory-certified mechanic for nearly brands of outboards, so his surveys go deeper than just diagnostics.) Scanlan said that hooking up a laptop to an engine—every manufacturer uses a different connector, so Scanlan carries one laptop and a pile of cords—is like accessing a person'due south medical records. "Maybe you lot broke your leg playing street hockey when you were a teenager. It healed up, but it's nonetheless in your records. Same with an engine," he said. "The diagnostics shows what happened and when it happened, during what hour of operation, downwards to the tenth of an hour."

A full inspection includes all outboard systems, not simply the engine. Tilt, prop, exhaust, ignition and more should be examined closely.

I tagged forth with Scanlan on his survey of a center console with twin 300-hp Suzuki outboards. In one case his laptop was plugged into the data port on an engine, K.E.D.S. first scanned for active fault codes; serious faults display in ruddy, others in orange. "I expect for error codes even before I do the sea trial," he said. "I don't start the engine, simply just switch on the ignition. Any fault codes and I stop the survey. They have to be repaired." With the engines running, Scanlan's computer pulled up a consummate dossier on each motor: How many full hours of functioning (681.2 for one engine, 681.5 for the other); how many hours at various RPM settings—these motors had nearly xx percent broad-open-throttle operation, which was fine with Scanlan; when the oil was final changed (42.five hours of running time ago, for both engines); were there any past faults, like overheating, low oil pressure or diverse sensor failures—there were none. If at that place had been, the program would have provided more information.

Scanlan then ran the cylinder drop examination, sort of a virtual compression test: M.Due east.D.Due south. shuts down one cylinder at a fourth dimension. With electronic ignition and fuel injection, software tin practice that, and information technology records the drop in RPM, displaying the results graphically. All cylinders should accept the same upshot when dropped; if one has less effect when cutting off, there's a problem with that cylinder, and further investigation is necessary. The surveyor doesn't fix the problems simply should exist able to propose the interested parties on how to keep. (Surveys, afterwards all, are performed to locate and evaluate deficiencies in a vessel that could affect the purchase price, or kill the deal completely.)

In our case, everything was copacetic. After the boat was hauled, Scanlan checked the lower-unit oil for water or signs of overheating—the oil would olfactory property burned and/or appear milky—and looked for metal filings on the magnetic drain plug, which indicate gear wear. Again, nothing. He checked the stainless-steel props for impairment and looked for reconditioning numbers on the hubs. "If the props have been reconditioned, maybe they striking something; in that instance, you demand to bank check the shaft, also," Scanlan said. He inspected the tilt/trim cylinders for leaking oil and looked for corrosion in the nooks and crannies of the engine mount, where many folks don't rinse off the salt thoroughly afterward a run. No problems here, either. Finally, he pumped environmentally friendly antifreeze from a tank in his van through the outboards to winterize them, as a courtesy. "I purchase it past the 55-gallon drum," he said. Scanlan would later print out the M.E.D.Southward. results and transport them to his client, along with his recommendations.

John Banister, on the other manus, doesn't worry about winterizing—he covers Florida from Daytona to the Keys from his store in Palm Beach Gardens. Banister is a factory-certified technician for most outboards and some gasoline inboards; he doesn't survey or work on gas engines, for which he is not certified, nor on diesels. His engine surveys become very deep into the motor; as a mechanic, he's not agape of taking things apart when necessary. But earlier hiring a surveyor, he said, get online and look for recalls for the engine, or service bulletins. Report the service invoices; maintenance and repairs should be done past reputable shops, following the factory schedule. Has the lower unit been checked? When was the water pump serviced? What about timing belt replacements? "Before you put any money in escrow, get a bounding main trial," he said. "Run the gunkhole at full throttle to make sure it can go to max rated RPM." When the engine'south warm, you shouldn't smell whatsoever gas, he added.

Think yous have the tools to inspect an outboard yourself? Recall again.

Two common bug Banister sees are corrosion from not-use of the engine (I thought folks in Florida went boating all the time!), and phase separation of gasoline that's been left in the tank for too long. Corrosion can be more dissentious than not servicing the engine. "I'd rather encounter an engine with higher hours than ane that's not been used," he said. Phase separation lowers the octane of the gas, which in plow causes the fuel to detonate rather than burn down evenly. This tin damage the engine. The all-time cure for phase-separated gas is to empty the tank and refill it with fresh, ideally non-ethanol, fuel. During every survey, Banister takes a sample of gasoline from the motor's injector rail and checks the quality.

His surveys also include estimator diagnostics, using one of two programs he owns; thermal imaging of the engine under load to look for overheating (the thermostat's at the top of the powerhead, so overheating usually starts at the bottom); an inductive ignition test—a magnetic sensor touched to the ignition coils shows the voltage for each 1; and a conventional compression exam. If a cylinder shows low compression, he'll eject a little oil in and do the test over again. If the compression increases, it'southward probably a piston-ring problem. (This will testify upwardly as excess chromium on the oil analysis, which Banister also does for each engine.) Otherwise, he performs a leak-downward examination: After manually cranking the engine to bring a given cylinder to top dead center, when both intake and exhaust valves are closed, Banister then pumps in about 90 psi of compressed air. A approximate shows how long the cylinder holds the pressure level. As the force per unit area falls, Banister listens for escaping air. If it comes out through the hub exhaust, there'south an exhaust valve trouble; through the air intake, it's an intake valve; through the dipstick tube, probably a damaged piston ring that's letting air into the crankcase. Valve problems are mostly caused past internal corrosion, he said. A corroded valve doesn't seat properly, which causes it to overheat—the valve's cooled by resting confronting the motor's water-cooled head. A hot valve can act like a spark plug, detonating the gas every bit before long as it'southward injected rather than when it should be firing off.

A reputable engine surveyor should be an experienced mechanic certified for the engine under consideration, Banister advised. He or she volition know what's going on inside the engine and be able to make an informed analysis of whatever issues evidence up during the survey—and there are frequently more than one. And not everything that can toll y'all coin has a sensor, and so diagnostic testing alone isn't plenty. This is where experience comes in: "At that place's no substitute for cranking on wrenches," Banister said. Expect the engine survey to take at least half a twenty-four hours for twins, a full day for triples and quads, and to cost—well, more than you might think if you hire a qualified person. For example, Banister charges $650 to survey a pair of Yamaha inline fours, including fluid analysis, and prices go up from there. But he often finds bug that a more than full general survey wouldn't reveal, issues that can cost thousands of dollars to repair. Then, I repeat: Don't be a sap when you buy your adjacent outboard. Get out your checkbook and hire a top-notch engine surveyor to ensure the motors yous're buying are up to snuff. Information technology could exist money well spent.

This article originally appeared in the Feb 2022 issue of Ability & Motoryacht magazine.

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Source: https://www.powerandmotoryacht.com/maintenance/how-to-survey-outboards

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