Rebuilding a motor? Please read our Tutorial for tips on a successful rebuild. |
Compression varies between motors, generally it is 125-150 PSI, but some motors run as low as 95 PSI. The general rule for compression is: From the Highest to the Lowest cylinder, compression should not vary more than 10 PSI. If you have 125 in #1, 125 in #2, 120 in #4, 120 in #5, and 90 in #6 The motor has a problem. |
It doesn't take much for an outboard to run. Like any Motor, Compression, Fuel, and Ignition. When we buy motors all I check is Compression and Bearing Wear. If the Motor has Compression and the Bearings are not "Loose", everything else is easy to fix. When buying a motor, check compression. The number will, generally, be about 125, although many motors run in the 90-100 range. MAKE SURE THAT FROM THE HIGHEST TO THE LOWEST CYLINDER THE COMPRESSION DOES NOT VARY MORE THAN 10%. We check Bearing Play with a Dial Indicator, but you can easily check for loose bearings with a long screwdriver. With ALL the spark plugs removed, place the screwdriver in a cylinder until you feel it touch the piston. Slowly rotate the flywheel until the piston is going DOWN. Stop turning the flywheel and "Push" on the screwdriver. THERE SHOULD BE NO NOTICABLE MOVEMENT IN THE PISTON TRAVEL. Try it several times on EACH cylinder until you have determined that there is no "Play" in the bearings. If there is a problem it is generally easy to notice. Any Questions, feel free to Contact Us. |
Props are matched by Horsepower and Weight. Everybody thinks that "More Pitch Goes Faster". Well, that's true to a point, but you have to have the motor to spin the bigger pitch. PITCH: The numbers on a prop are "DIAMETER X PITCH". A 15X19 Prop is 15" Diameter and 19" Pitch. Diameter is just what it sounds like. Pitch is the distance the prop would move forward, in 1 Revolution, in a "Solid", so this prop would move 19 inches forward if it DID NOT SLIP AT ALL. Generally, you want a motor to run AT LEAST 5000 RPM [Full Throttle] and a MAXIMUM of 6000 [Higher on Performance Motors]. 5500 is ideal. Too LOW RPM needs LESS Pitch. Too HIGH RPM needs MORE Pitch. RUNNING THE WRONG PROP CAN DO SERIOUS DAMAGE TO A MOTOR! |
The only "Sure Fire" way to store an outboard motor is to RUN it on a hose every month, but if you must leave it you will have to Drain the Carbs. This is NOT the same as Running it "Dry". You MUST Remove the drain screw, found on the Float Bowl of EACH Carb and remove it to Drain the Fuel. Then blow air though the lines to clear ALL fuel from the system. There is NO "Magic" you can pour in the tank to keep the Carbs from Clogging. REMEMBER: When you pull it back out for the next season, If it Doesn't Run RIGHT, DON'T RUN IT. Get the Carbs Rebuilt by a Shop that has the Acid you MUST Soak them in. Simply taking them apart and "Cleaning" them DOES NOT WORK and could COST YOU A MOTOR. |
The most common problem with "No Spark" is in the "Kill" system. Almost always it is an Ignition Switch. They tend to "Short" internally and cause a "No Spark" condition. If your boat uses a key switch, check the spark with the wiring harness DISCONNECTED. CAUTION: Remove ALL plug wires to keep motor from starting. Generally you will not have a situation with "No Spark" on ANY cyclinder, most common problems are lack of Spark to a couple of cylinders. Obviously this varies by motor, so if the diconnection of the harness does not help, Contact Us for further assistance. |
Frequently Asked Questions These are Very General answers to common questions about Outboard Motors If you have a Specific Question, feel free to Contact Us for Further Assistance |
Outboard Motors do NOT sit well. Carbs tend to "Gum Up" main jet nozzles. The problem is, by design, an outboard motor, regaurdless of size, is a series of ONE cylinder motors connected at the crankshaft. Each cylinder is controlled by a single carb. Some do share a carb between TWO cylinders, but the problem is the same. The motors will generally start on the Idle circuit, and Idle, but as soon as you throttle up to a point were the Main jet begins to work, it Starves for fuel. The real DANGER is the other cylinders do NOT know that one or more main jets are blocked and those cylinders try to run. The cylinders that are NOT getting fuel, are NOT GETTING OIL EITHER! The result is the destruction of the piston and cylinder wall, and it's REBUILD TIME. The bigger the motor, the worse the problem. If the motor only runs with the Choke on, it is a sure bet that the carbs are bad. 80% of the Motors we buy and rebuild are a direct result of trying to run the motor without rebuilding the carbs after sitting. RULE: If it does not run well, DO NOT RUN IT! |
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Outboard Motors do NOT sit well. Carbs tend to "Gum Up" main jet nozzles. The problem is, by design, an outboard motor, regaurdless of size, is a series of ONE cylinder motors connected at the crankshaft. Each cylinder is controlled by a single carb. Some do share a carb between TWO cylinders, but the problem is the same. The motors will generally start on the Idle circuit, and Idle, but as soon as you throttle up to a point were the Main jet begins to work, it Starves for fuel. The real DANGER is the other cylinders do NOT know that one or more main jets are blocked and those cylinders try to run. The cylinders that are NOT getting fuel, are NOT GETTING OIL EITHER! The result is the destruction of the piston and cylinder wall, and it's REBUILD TIME. The bigger the motor, the worse the problem. If the motor only runs with the Choke on, it is a sure bet that the carbs are bad. 80% of the Motors we buy and rebuild are a direct result of trying to run the motor without rebuilding the carbs after sitting. RULE: If it does not run well, DO NOT RUN IT! |
Frequently Asked Questions These are Very General answers to common questions about Outboard Motors If you have a Specific Question, feel free to Contact Us for Further Assistance |
The most common problem with "No Spark" is in the "Kill" system. Almost always it is an Ignition Switch. They tend to "Short" internally and cause a "No Spark" condition. If your boat uses a key switch, check the spark with the wiring harness DISCONNECTED. CAUTION: Remove ALL plug wires to keep motor from starting. Generally you will not have a situation with "No Spark" on ANY cyclinder, most common problems are lack of Spark to a couple of cylinders. Obviously this varies by motor, so if the diconnection of the harness does not help, Contact Us for further assistance. |
The only "Sure Fire" way to store an outboard motor is to RUN it on a hose every month, but if you must leave it you will have to Drain the Carbs. This is NOT the same as Running it "Dry". You MUST Remove the drain screw, found on the Float Bowl of EACH Carb and remove it to Drain the Fuel. Then blow air though the lines to clear ALL fuel from the system. There is NO "Magic" you can pour in the tank to keep the Carbs from Clogging. REMEMBER: When you pull it back out for the next season, If it Doesn't Run RIGHT, DON'T RUN IT. Get the Carbs Rebuilt by a Shop that has the Acid you MUST Soak them in. Simply taking them apart and "Cleaning" them DOES NOT WORK and could COST YOU A MOTOR. |
Props are matched by Horsepower and Weight. Everybody thinks that "More Pitch Goes Faster". Well, that's true to a point, but you have to have the motor to spin the bigger pitch. PITCH: The numbers on a prop are "DIAMETER X PITCH". A 15X19 Prop is 15" Diameter and 19" Pitch. Diameter is just what it sounds like. Pitch is the distance the prop would move forward, in 1 Revolution, in a "Solid", so this prop would move 19 inches forward if it DID NOT SLIP AT ALL. Generally, you want a motor to run AT LEAST 5000 RPM [Full Throttle] and a MAXIMUM of 6000 [Higher on Performance Motors]. 5500 is ideal. Too LOW RPM needs LESS Pitch. Too HIGH RPM needs MORE Pitch. RUNNING THE WRONG PROP CAN DO SERIOUS DAMAGE TO A MOTOR! |
It doesn't take much for an outboard to run. Like any Motor, Compression, Fuel, and Ignition. When we buy motors all I check is Compression and Bearing Wear. If the Motor has Compression and the Bearings are not "Loose", everything else is easy to fix. When buying a motor, check compression. The number will, generally, be about 125, although many motors run in the 90-100 range. MAKE SURE THAT FROM THE HIGHEST TO THE LOWEST CYLINDER THE COMPRESSION DOES NOT VARY MORE THAN 10%. We check Bearing Play with a Dial Indicator, but you can easily check for loose bearings with a long screwdriver. With ALL the spark plugs removed, place the screwdriver in a cylinder until you feel it touch the piston. Slowly rotate the flywheel until the piston is going DOWN. Stop turning the flywheel and "Push" on the screwdriver. THERE SHOULD BE NO NOTICABLE MOVEMENT IN THE PISTON TRAVEL. Try it several times on EACH cylinder until you have determined that there is no "Play" in the bearings. If there is a problem it is generally easy to notice. Any Questions, feel free to Contact Us. |
Compression varies between motors, generally it is 125-150 PSI, but some motors run as low as 95 PSI. The general rule for compression is: From the Highest to the Lowest cylinder, compression should not vary more than 10 PSI. If you have 125 in #1, 125 in #2, 120 in #4, 120 in #5, and 90 in #6 The motor has a problem. |
Rebuilding a motor? Please read our Tutorial for tips on a successful rebuild. |
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