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Compression test ?
- Thread starter slowboatn
- Start date
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Here is some info on doing a compression test.
You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)Screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem. I hope this helps you.
Karl
You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)Screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem. I hope this helps you.
Karl
That's correct, because of the resistance from the water it reduces the rpm's of the engine.
Karl
Karl
If you rebuild the carbs chances it will need to be adjusted. It's not a big deal...just keep an eye on the RPM's. sometimes the adjustment just loosens up over time or the adjustment wears a little to cause it to be off.
Karl
Karl
I would adjust the carbs idle, if it is too low. If the boat is giving you problems the carbs might need a cleaning. Sometimes it solves any carb problems just by doing a cleaning. Keep us posted if you have any other problems.
Karl
Karl
I couldn't remember if you posted a problem or not before this thread. I would pull the carbs and clean them. Pay close attention to the small internal filters. Be careful not to damage or tear the diaphragms. Pay close attention to the small internal filters. If you do, you'll have to purchase a rebuild kit...cost about $40.00 each carb.
Karl
Karl
Here is an idea for you. If you want you could join as a "premium member". As a premium member you can down load a authentic seadoo manual from the seadoo manual library. In the library is a variety of manuals for almost all years and models. You can view as many as you like on line as a PDF file, or download it and print it for your personal and privet use. There are operator manuals and repair manuals for you to do your own repairs on your seadoo. The repair manuals have everything from troubleshooting, repair procedures to winterizing. It contains wire diagrams torque specs and pictures for disassemble and assemble instructions. In the spec sheets it tells everything needed to maintain oil changes, spark plug gaps, carburetor rebuilds and impeller wear ring tolerances. Click on the "Seadoo Manuals" link at the top of the page for more details. If you need any help or get in a jam, we are always here to answer your questions too.
Karl
Karl
It's not a sales pitch...I bought a manual for my speedster from the seadoo dealer and it cost me $85.00. I wanted the complete manual in paper for my own boat and to help members here solve problems too. I just became a moderator. I was a premium member till uh yesterday...I was asked to be a staff member because of my knowledge. This position pays nothing...it's all volunteer. The price of a manual for $10.95... is the best price I have every seen. it helps keep the forum on line and reduce the advertisers on popups. I just couldn't get one for my boat as it is so new, from the forum.
Karl
Karl
Valve Things
Valve things......? RAVE valves? Rotary Valves? Water Flow Regulator Valve?
There are lots of "valve things". :ack:
Karl
Valve things......? RAVE valves? Rotary Valves? Water Flow Regulator Valve?
There are lots of "valve things". :ack:
Karl
timmyboy76
New Member
compression testing...
Hey Karl.....
First off, Hats off to you and Seadoosnipe, secondly, you describe about compression testing, just curious though...when would be a good time if any to due this, when motor is cold, swarm, or when you just did a plug check...Thanks again
Hey Karl.....
First off, Hats off to you and Seadoosnipe, secondly, you describe about compression testing, just curious though...when would be a good time if any to due this, when motor is cold, swarm, or when you just did a plug check...Thanks again
timmyboy76
New Member
bump...
curious about the last post from me....
curious about the last post from me....
Here is some information on the RAVE valves and followed by compression check information. Let me know if you still have questions.The RAVE, (Rotax Adjustable Variable Exhaust) valves are located above the exhaust valve. There are 2 of them per engine. They are round with a red adjustment screw in the middle. It has a clip that holds it together. How they work is that they open the exhaust port larger as the engine rpm's increase. When the rpm's drop down so do the RAVE valves. They work on the principle of the pressure of the exhaust system. Rpm's increase, pressure increases and the valve opens, rpm's drop pressure drops, Valve closes. They should be de-carbonized annual. To disassemble the rave valves, remove the spring clip on top, remove the black cover. There is a spring under the cover. Remove the piston by turning it with a metric socket. On the bottom of the piston is the rubber "Bellows" be careful with the small retaining spring that hold the bellows on the piston. Remove the 2 allen screws that hold the base on the cylinder. Remove the base and gasket. The long valve won't fall in the cylinder just pull it out. There is an o ring under the base, on the shaft of the guillotine valve. Be careful to see how it came apart as it has to go back together that same way again. On the base, notice the notch that it is facing down. Clean all the carbon off the guillotine valve. I use carb cleaner and 400 grit paper. Check the bellows for any small pin holes. If so replace it. If not, reassemble it on the clean guillotine valve, and install it back on the engine the same way it came apart. The guillotine valve only fits one way. The one closest to the exhaust pipe will come off differently then the other one. You will have to remove the allen screws and turn the base so it clears the exhaust pipe. I would do one at a time in case you forget how it goes back together again. This way you can look at the other one and copy it. Take your time and if you have questions give us a shout. We'll be here to help you out.
If the RAVE valves are dirty it will not rev up correctly and could be causing your problem.
The adjustment knob (the red cap) should either be screwed all the way in or flush to the top of the black ring of the cap. This will only affect performance, as far as how it jumps out of the hole or how well it runs for extended periods at WOT.
To do a compression check you can get good results either cold or warm. I perfer a warm engine, but sometimes you can t get it to fire up, due to lack of good compression.
You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)Screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem. I hope this helps you.
Karl
If the RAVE valves are dirty it will not rev up correctly and could be causing your problem.
The adjustment knob (the red cap) should either be screwed all the way in or flush to the top of the black ring of the cap. This will only affect performance, as far as how it jumps out of the hole or how well it runs for extended periods at WOT.
To do a compression check you can get good results either cold or warm. I perfer a warm engine, but sometimes you can t get it to fire up, due to lack of good compression.
You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)Screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem. I hope this helps you.
Karl
timmyboy76
New Member
Thanks Karl...
Any more Questions give me a shout...I aim to please...
Karl
Karl
Thank you...keep us posted on your progress. You know we're here to help.
Karl
Karl
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