Thread: Compression Test for my SJ
02-02-2010, 06:49 PM #1
Compression Test for my SJ
I purchased a tool to check compression on my 701cc engine for my super jet. When doing the test, should I take out both spark plugs at once and test each one? Or should I take out one spark plug, test the compression and put back the spark plug before I test the next one? What is the proper way? Also what should my compression be? Also, how long should I hold the green starter switch to properly test? Thanks!!!
02-02-2010, 10:41 PM #2
Both plugs out
Ground spark plug leads as to not burn out the coil
Make sure the battery is fully charged, or use a jumper pack so that the engine spins over at full starter speed.
3 or 4 revolutions should be enough.
Ideally you want to do it with a fully warm engine, but cold will be ok.
Your cranking PSI will vary with mods and porting. Tell us what you get and any mods and we can go from there.
02-03-2010, 10:11 AM #3
stupid question. How do you ground the spark plug leads? I had water in my cylinders a few weeks ago which I got out. BUt by doing so, I think I may have burned out the coil as I did not ground the spark plug leads.
02-03-2010, 05:11 PM #4
If you have any bolts exposed on the engine, just slip the plug boot over the end of the bolt. One for each plug wire.
I know older Seadoos had a "bracket" that you could use.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By mattb2179 in forum Polaris Open DiscussionReplies: 13Last Post: 08-29-2007, 09:51 PM
By vadik85 in forum Yamaha PWC Performance (2-stroke)Replies: 10Last Post: 08-19-2007, 09:41 AM
By davidescu_radu in forum Yamaha PWC Performance (4-stroke)Replies: 0Last Post: 07-28-2007, 01:19 AM
By HiPeRcO in forum 4-Tec PerformanceReplies: 4Last Post: 07-25-2007, 06:38 PM
By Red Devil in forum 4-Tec PerformanceReplies: 9Last Post: 06-01-2007, 12:05 AM