How to check compression on a pwc 2 stroke engine. YAMAHA 62t Dasa 1200 16mm stroker

In this video I go through the steps to check compression on a PWC 2 stroke. In this video I'm testing the compression on a fresh 1200 CC Dasa 16 mil stroker power valve motor but it's the same procedure for most pwc 2 strokes. Yamaha 650, 701, 760, 800, 1100, 1200 Kawasaki 440, 550, 650, 750, 800, 900, 1100, 1200 ect..
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[@ryandresang6251]

Really enjoying all of the content! Been building skis for a couple of years now and finding your videos really beneficial.

[@EricksonMachinePerformance]

Thanks for watching!!

[@doobyboy21]

I keep seeing videos on KZbin saying that you don't need to hold the throttle open to do a compression test... Happy I am subscribed to you ! This is like if you need to go see a dentist go see one and not your uncle Ronny !

[@EricksonMachinePerformance]

To be fair some engines don't need to hold the throttle open To get an accurate reading but others do so holding the throttle open will always give you the correct number having the throttle closed will sometimes give you the correct number which is the reason I recommend to always hold it WOT

[@nickdean8758]

can you do a video for what you recommend for breaking in a fresh rebuild? seems to have always been a controversial topic and everybody has their own methods. what you recommend for oil, mixture, how long it takes, riding style etc. I would rather take the advice of somebody who builds motors all the time(and makes videos to prove it) rather than some random guy.

[@EricksonMachinePerformance]

Great idea. I will definitely do that!!

[@mikecataldo4398]

Absolutely love the content you're putting out, so informative and instructional I've used several videos to do my own repairs. Can you recommend a relatively inexpensive compression test kit? I made the mistake of trying a crappy one from Harbor Freight, completely inaccurate 🥴, waste of money

[@EricksonMachinePerformance]

Buy a used Snapon, Mac or Matco. My favorite is Matco. U can normally pickup for around $100 used and just replace the schrader valves and they are as good as new

[@mikecataldo4398]

@@EricksonMachinePerformance thanks for the info, ended up getting a Matco CT110K Master Compression Tester Kit for 130 bucks

[@EricksonMachinePerformance]

@@mikecataldo4398 that's what I use as my main gauge. Enjoy it!

[@williamjager7289]

Does it matter if the motor is at running temps or not when taking a compression test ?

[@EricksonMachinePerformance]

That's kind of a loaded question. The real answer is yes it should be warmed up. That being said many times it doesn't matter ( but sometimes it does)

[@joverbuhok5222]

Nice video... Can u make video rebuilding 1000cc or engine has diaphragm on the exhaust... I don't know exactly if that one is diaphragm... The circle top of the exhaust

[@EricksonMachinePerformance]

Yes I can. They are called powervalves

[@markcurtis8111]

Hi Great video, I have a Dasa 1200 16mil, did compression when it was new ( 170 psi ) did it again 20 hours on engine later, it is 165psi , this seems really low compared to your readings , (210psi plus) but i am running Uk Pump gas @99 octane so was expecting 190 ish, I only have a cheap gauge, both pots are the same

[@EricksonMachinePerformance]

Email me. [e-mail] It could be you have pump gas domes. This was a race fuel setup

[@markcurtis8111]

@@EricksonMachinePerformance Thanks Erick, yer they are pump gas domes, 48 / 95 but I would expect more than 165psi , what should they give do you think.

[@EricksonMachinePerformance]

@@markcurtis8111 are sea-level?

[@markcurtis8111]

@@EricksonMachinePerformance Yep London Uk

[@EricksonMachinePerformance]

@@markcurtis8111 if they are even my guess is ur gauge is reading 10psi low. VERY COMMON with cheap gages to be off. I would worry about it unless you have Performance issuse

[@96superjet]

May be worth mentioning, I typically depress the kill switch as I’m turning over the motor. I’ve been told it disables any active spark from traveling down your plug wires. I can’t verify because I’m unwilling to hold a plug wire while doing it 😳

[@EricksonMachinePerformance]

That works with some skis but not all. Also grounding the plug or just keeping the total loss brain off. Some cdi are more fragile then others. Seadoo is by far the most fragile to damage. Normally skis that are know to be susceptible to damage have grounding posts on the ebox. But it's a good practice.

[@extreme9495]

No 61x 700, qual é a compressão original? O meu está em 125psi.

[@rafaelbautista9221]

Question Yamaha 2000 xl800 one cylinder compression it’s at 70 and the other one it’s at 0 completely any help will be appreciated

[@marcels.1225]

Is there a difference in keeping the second sparkplug in while testing for compression? Great videos!

[@EricksonMachinePerformance]

It depends on the engine. I prefer to remove all plugs before test

[@tylynblaylock]

Group K suggests to leave your other plug in. Why do you suggest leaving it out?

[@EricksonMachinePerformance]

There's pluses and minuses to both methods. But leaving them out won't give false readings as often ( in my opinion I have tested both ways and this is what I have found to be the most accurate )

[@bakeblaker01]

Hey nice video. I did a test on a TS Barracuda 640 but I didn't hold the throttle open. I got 155 on both with my not too expensive guage. What is the reason for holding the throttle open? I'll have to recheck and see the difference. Thanks, saw your video on Yamaha Superjet page fyi

[@EricksonMachinePerformance]

Checking without opening the throttle can give u a false reading because the engine cant suck enough air past the butterfly's and it can give you a lower reading by a few psi

[@jkgkjgkijk]

Why wide open throttle? Same for 2cyclw?

[@EricksonMachinePerformance]

Wide open throttle is mainly for 2 strokes. SOMETIMES with the throttle blades closed it can lower compression ( very little ). It is a good rule to follow but does not always make a difference.

[@martinollendorff1201]

Hi I used cheap compression testers in the past with mixed and unreliable results. Now I have been using a snap on tester however I noticed that you use a universal tip that does not screw in very deep? I have that version and another one that has the same length as a spark plug.when using the universal one I get a big difference of compression than using the other longer hose that screws in deeper. The result is 12psi more with the longer threaded one? Which one is the correct one to use? I almost feel like the one that is close to the length as a spark plug in threads should yield the correct results?

[@EricksonMachinePerformance]

Mine read within 2 or 3 psi of each other. If your looking for EXACT #s then its best to use the adapter that's the same size as the spark plug. If your checking for engine health, as in if the holes are running the same it really doesn't matter.