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To know whether low compression is the problem or not always use a compression tester. Results vary depending on whether the outboard is a Four-Stroke or a Two-Stroke.
Measure or gauge the amount of bounce you feel on your hand as each of those pistons pass the top dead center TDC stroke position.
Outboard motor compression test results. What Outboard Compression Test Results Mean. Results vary depending on whether the outboard is a Four-Stroke or a Two-Stroke. Good results for Four-Strokes should be 180-210 PSI and Two-Strokes should be around 110-130 PSI.
Here is everything that you need to. Interpreting The Results. The next step involved on how to test outboard motor compression will be to determine your readings.
Typically a reading that comes up below 90 PSI on the modern 2-stroke outboard engines indicates an issue. What Outboard Compression TEST RESULTS Tell You. If playback doesnt begin shortly try restarting your device.
One gauge will tell you the pressure of the air compressing the cylinder. The second gauge will show you how much pressure has been lost. With this method the cylinder has to be TDC or top dead center in order to get a correct reading.
The second method to compression test an outboard uses a single gauge. 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. This test can be performed without a compression gauge.
First turn the outboard motor over by hand using the recoil start ideally at the normal starting pull speed. Measure or gauge the amount of bounce you feel on your hand as each of those pistons pass the top dead center TDC stroke position. If the engine is healthy the bounce is easily detectable.
An outboard gas engine needs air spark compression and unobstructed exhaust in the right amounts and at the right time. As the piston travels up and down in the cylinder the piston rings seal against the cylinder wall so the airfuel mixture can be compressed at the top of. A compression test is still the best test for a 2-Stroke engine and should be performed before any repair service is done on a 2 stroke engine.
130 130 120 are good numbers just check it every year when your annual service is done to make sure the gap doesnt widen. This equates to about 116th of a turn beyond hand tight. The majority of all outboards will give readings in the 115 to 150 psi range any less and either the motor is well worn or the compression gauge may be suspect.
A lot has to do with knowing your. Good point roscoe And my answer is yes there is some value in performing a cold compression test Particularly on an engine that will not start when all else seems to be in lineCarburetionsparketcA cold compression reading of say40 would not likely or moreover notincrease to acceptable levels on warm engine and could very well prevent startupOn the other. Before diving into the thought of having an outboard with low compression you have to make sure of it first.
To know whether low compression is the problem or not always use a compression tester. Use the compression tester to detect whether its the compression or another part of the engine thats causing the problem. Best compression tester for outboard motors.
So theoretically performing a compression check with an absolute pressure gauge the result would be 1322 psi. Doing the test with a gauge that reads gauge pressure at sea level 0 psi the value would be 1322 minus 147 or 1176 psi. Now we have got.
A compression test by the way measures how much each piston is compressing the air in the cylinder using a simple gauge threaded into the spark plug port. Compression-testing a cold engine wont give accurate results so the engine has to be warmed up to. 12-04-2016 1143 AM.
On two stroke a compression test is quick easy and painless. On a 4 stroke it is a teat on a boar hog. I cannot tell you how many 4 strokes have passed a compression test with leaking headsleaking valves and stuck rings due to carbon.
Yet the compression was good and the leakage rate above 70. If your motor has been stored for a prolonged period of time the piston rings might be relaxed. In this instance compression results will read low.
Make sure to run the engine to normal operating temperatures to acquire an accurate cylinder compression reading. Begin by disabling the engines ignition system by disconnecting the lanyard clip. How to Compression Test an Outboard Motor BoatUS - YouTube.
For a compression test the engine itself provides the pressurization. For each cylinder remove the spark plug and screw in the fitting that the gauge connects to. With the coils disconnected so the engine doesnt start crank the engine for about 10 seconds.
The gauge on the tester will register at the highest indicated compression reading. What should the PSI be on an outboard compression test. Results vary depending on whether the outboard is a Four-Stroke or a Two-Stroke.
Good results for Four-Strokes should be 180-210 PSI and Two-Strokes should be around 110-130 PSI. Here is everything that you need to know about outboard compression tests. What compression should an outboard motor have.
How much does a compression test cost. The average cost for engine compression test is between 127 and 161. Labor costs are estimated between 127 and 161.
This range does not include taxes and fees and does not factor in your unique location. Related repairs may also be needed. As there are numerous options available in the market you may find it difficult to choose a better option in the market.
Table of Contents hide Best Buy Compression Tester Reviews. INNOVA 3612 Compression Tester. BETOOLL HW0130 Compression Tester Kit.
A compression test can be used to compare the compression of one cylinder to the others. An engines cylinders need a good seal between the piston rings and the cylinder walls and between the valves and their respective seats. Wet Compression Test Diagnosis.
The results of a. Repeat testing for all cylinders and compare results. Readings will vary from gauge to gauge so the test is more about measuring the difference in readings with ideal results being less than 10 percent variance.
After the compression test is completed or skipped you can now begin installing your new spark plugs.