How to compression test outboard

Good results for a two-stroke engine are between 110 and 130 PSI. Older two cycle outboards especially low horsepower can run fine around 60 psi however above 90 psi is optimal.

Remove the three latches that hold the cowling in place.

How to compression test outboard. There are a few things that need to be done to compression test an outboard correctly. First get the engine to operating temperature. The pistons and rings need to expand to their normal size when the engine is at its operating temperature.

How to Compression Test an Outboard Motor BoatUS - YouTube. How To Compression Test an Outboard Motor - YouTube. How to Test Outboard Motor Compression.

Compression checks can be used to let you know about how well the outboard engine is working. When it comes to How to test outboard motor compression it is important to know about the four phases that are distinct in a 4-stroke cycle. This will include the exhaust power compression and induction.

HOW TO DO A OUTBOARD COMPRESSION TEST - YouTube. How to perform a basic compression test on any outboard motor also a description of tools needed. How to perform a.

Primary Compression Test Your 2-stroke outboard powerhead is an efficient pump. The crankcase must be completely sealed against pressure created upon the down stroke of the piston and the vacuum thats created when the cylinders piston moves upward back to. How Do You Do A Compression Test On An Outboard Motor.

Performing the compression test is actually a pretty simple process. You are going to want to take off any of those covers that we talked about earlier from over the top of the ignition coils. Once you are looking at your engine and you get the ignition coils exposed.

Attach the compression test adapter into the cylinder nearest the front of the engine then connect the gauge to the other end of the adapter hose. To perform the test crank the engine 4 times by turning the key in your cars ignition then. Testing Compression on an Outboard.

Remove the three latches that hold the cowling in place. One on the front of the motor. One on the left side.

And one on the right side. Once all three are unlatched you can lift off the cowling. How do I do a compression test.

Disconnect the fuel line pull all the plugs turn over the motor by crossing the starter connections. They should all read around 110 - 120 and all be within 10 psi of each other. How to - outboard compression check Probably best to post this in the outboard repair forum for your engine make.

• Get a engine compression tester - Test can be performed out of the water on the hose - Warm up the engine - remove the spark plugs - screw compression tester into one of the cylinders - crank the engine a few cranks. Ensure that your battery is fully charged. If your battery is weak your starter turns over more slowly which will cause a low reading.

Screw the end of the compression gauge into one cylinder. Go to the key and turn the engine over for 3 to 5 seconds. It doesnt matter whether you turn it over for 3 or 5 seconds.

Set the throttle wide open and then pull the pull cord six or seven times to test the compression. Next check the gauge on the compression tester. Johnsons specs are for the engines compression to be between 85 and 90 PSI so this cylinder passes.

Like gaskets pistons are a critical component to the Outboard. Hence you must do a compression test and detect whether its a pistons ring issue or not. If you find it to be low then replace the piston rings to avoid further damage.

To detect valve issues like leaky valves run the motor. I am planning to do a compression test for the first time on my 1996 Mercury 150hp 2-stroke outboard. I have read many posts in this forum on compression testing and they mostly agree that it is important to properly ground the wires to avoid damaging the electrical system.

Older two cycle outboards especially low horsepower can run fine around 60 psi however above 90 psi is optimal. Four strokecycle engines produce much higher compression. The main thing to check is the difference between cylinder compression.

Cylinder-to-cylinder compression readings that differ more than 10 reveal trouble. Compression Test 101. In a different thread townsend had mentioned a compression test which had me thinking.

If you were to google how to perform compression test for every link that provides instruction there are just as many conflicting procedures. Some say ground the plug cap some dont. How to Read Outboard Compression Test Results.

Check the service manual on your outboard for the precise specifications. Remember that if your engine is cold the results will be slightly lower. Good results for a two-stroke engine are between 110 and 130 PSI.

For a four-stroke good results are between 180 to 210 PSI.